http://www.actron.com/cgi-bin/web_st...17.htm&cart_id

Others have indicated this unit threads right into the fuel line. I believe Autozone sells them for $40.

Your dash gauge indicated 160F with a 195 stat?! Now the dash gauge indicates 140F with a 180 stat? That sounds fishy. It might explain the boiling at temps under 212F if the gauge is reading 40 degrees low. Or is that the Winaldl reading?

Regarding AE - I don't know what risk there would be. You will probably have to retune it once the fuel pressure issue gets settled.

I wouldn't tee any vacuum item into the MAP line. The MAP should have its own dedicated line. Perhaps you could try the unused EGR vacuum port for your HVAC controls.

 

I finally got around to doing some more chip burnin' this week...all I can say is it made a BIG difference. The pump shot table changes really helped alleviate my bog problem...although the car will still stumble severely if you gas it in 1st gear from a stand-still. Here are the data logs:

15% pump shot increase

25% pump shot increase

35% pump shot increase

I drove the car differently with each data log, so they may not be the best comparison in the world. Also, I forgot to unhook the vacuum line for my air vent controller (haven't re-routed it yet), so that may have been messing with the MAP. I collected some idle data on the 15% chip...of course, I managed to boil my coolant again in the process. I've still got to work on my fan switch issue...the fan will come on with the air, I just don't think it comes on due to the fan switch.

I ran a couple of "spirited" runs with the 25% chip...I just had to play around with my G-Tech. Of course, I won't bother to provide any details about the pathetically slow times I cut ...the bog in 1st gear is killer.

The 35% chip seemed to run the best according to my "seat of the pants" meter, so I left it in. Is there a way to objectively decide which pump shot increase worked the best based on the data logs? I tried evaluating my BLMs under acceleration from each data log, thinking that I would see them go rich if I had applied too much pump shot increase. However, all three looked pretty similar to me. I am still running a little rich in the 20-40 KPa x 400-1600 rpm range of the fuel table, but I'm definitely getting closer.

Brent, I am running WinALDL version 1.09d...wonder why we're getting different data output?

Also, regarding coolant temperature, you're correct...my temp gauge was reading 160F with a 195F thermostat and it is now reading 140-150F with a 180F thermostat. In addition, my CTS (WinALDL) reading reads even lower than the gauge...roughly 20-30F lower. I'm going to move the CTS once I get the right adapter and see if that corrects the temp differential...but I still have to figure out why I'm boiling my coolant at temps reading below 200F.

One last thing...I've got a 3.73 posi that I need to install sometime...do you think that will require a significant amount of extra tuning?

Thanks for the fuel pressure gauge info...

 

I am wondering if maybe you have the wrong water pump on the engine. There are two different rotation pumps dependent upon whether it is a serpentine setup or a V-belt drive. The V-belt uses a standard rotation pump, while the serpentine setup is a reverse rotation pump.

On a _warm_ engine open the radiator cap (caution: don't open the cap if under pressure!! Squeeze the upper hose first to check!), and run the engine. Note the direction of the coolant flow. Should be out of the engine, through the top hose, into the radiator, through the core, past the cap opening, then back into the engine.

Another way to check is to pull the rear cover off the water pump and note the direction of the fins on the rotor. Although will need another pump to compare it to.

RBob.

 

my last burn is at 250% for AE/TPS and MAP. over 4000 usec for TPS at 100%. this burn seemed to be the best. blms all at 126-132. PE set at 12.5/1. air temps were 50 deg F last weekend. my stumble all but gone when my manifold is heat soaked after a ride of 4 miles or so on cold engine start. depending on level of mods it would appear some cars can really eat up PS. see a posting by BEN. he is tuning a new motor. same issues. when my car was modded 4/03 if you accellerated any more than grandma it would cough and die and then start back up when momentum caught up with a killed engine. i too added 5-10% for AE and it took forever to get to this point as i was too conservative.

 

Thanks for the help, guys.

RBob - That's an interesting thought about the water pump...I hadn't considered that one yet. I swapped my factory water pump and serpentine setup over from my L03 305 to this engine, though...would it still be possible to have a wrong-rotation issue with that being the case?

Ronny - Wow! I can't believe you had to add so much to your Pump Shot vs. Differential TPS table. Do you mean that you added 250% to both that table as well as the Pump Shot vs. Differential MAP table? I haven't touched that one yet. Also, you mentioned that you added over 4000 usec @ 100% TPS...my table only goes up to 12.5% TPS. Is that just a difference in our ECMS? I'm running a 1228746 and it may be different...dunno. That's really encouraging that you've made so much progress with your setup...I'll be sure to do a search on what BEN is going through. One question...how do you know the difference between bogging due to running rich or running lean? I was a little concerned that I may have added too much on the low end and that was causing my stumble in 1st gear...just a thought.

 

Somehow I suspect the datalog and BLM update speeds aren't fast enough to reflect a misadjustment in AE. Perhaps if you had too much AE which dumped a large amount fuel you might see it reflected in the O2 or INT as the engine burned all that fuel off, but I think you would be noticing a bog at that point. I'd just increase it in increments till it quits hesistating then try backing it off in smaller increments to find the happy medium. Optimally you'd want to measure performance as a final test but thats for later.

Like Ronny mentions you may need to increase that table quite a bit. Some 454 trucks had values as high as 12000-13000.

Depends on how particular you are about having things perfect. You may get it running really nice and find that you are satisfied with the performance and safety of you tune. Others might continue to try and tweak every last ounce out of their combo. I don't think you'll *have* to put in much additional time to tune for the 3.73's.


You can unplug the AC compressor clutch and turn on the AC anytime you need the fan to run until you get the fan switch sorted out. Its a bit worrisome that the coolant is boiling.


Winaldl v1.09E just might fix the problem with the datalogs.

http://w1.601.telia.com/~u60113744/s...dl/aldlver.htm

 

Thanks, Brent...I'll just keep adding AE in 10-20% increments until the bog goes away. Should I also be adding the same amount to the Pump Shot vs. Differential MAP table?

Glad to hear the 3.73s shouldn't require "starting over" with this tuning exercise...I just wanted to make sure that I wasn't wasting my time tuning with my 3.08 pegleg for now.

As for the A/C, it's actually almost warm enough to run it with the compressor on...we're coming close to 80 degrees these days. Thanks for the tip, though.

I just downloaded WinALDL 1.09e...I'll have to wait until next week to load it on my company's laptop, though. My wife and I are heading to Gatlinburg, TN for a little vacation time before our baby's born in June (last chance...ha).

 

due to the mods i did i was of belief i was lean day one. all mods done at once cept the 2.00 TB's and 90 lb injectors. engine threw a lean code at daily driving. i considered the design of the xram and 2.00 inch TB and came to conclusion i could feed it air very easily with my foot. (2) 2.00 single TB's, large intake runners, 2.02 intake valves. blms optimized(almost) and WOT showed 12/1 on WB on dyno. BUT a stumble when i floor it. so 10% at a time in all AE TPS/MAP areas to maintain the GM base for AE. i found 2 350 GM bins and for AE i think it was max at 100% TPS of about 1500 usec. each burn was a little better. last one is there i believe.

 

This is a very good question and I'm not sure I have a really good understanding of how these should be tuned. In the past I mainly focused on the TPS table. That is probably the wrong approach. Hopefully some others will tell me if I've driven this one in the ditch.

The PS vs Diff MAP table seems to compensate for the differences in required AE based on RPM. That sounds strange but bear with me.

Lets say we increase the TPS delta 6% at 1000RPM and 40KPA. The MAP reading will increase from 40KPA to 70KPA.

If we increase the TPS delta 6% at 2500RPM and 40KPA, the MAP reading will increase from 40KPA to 55KPA. Less Delta MAP than the 1000RPM scenario.

In otherwords, the faster the engine is running the less Delta MAP we will find for a given Delta TPS.

The Delta MAP is also affected by what TPS% we started from because of the nature of the airflow around the throttle plates.

If we start from 0 TPS and open the throttle 10%, the increase in MAP is greater than if we start at 80% throttle and increase to 90% throttle.

Perhaps its best to try working with each table to see what works best. If the MAP table is ignored I suspect you'll end up with too much AE at higher RPMs. It does seem from looking at various 747 bins that the MAP AE table won't require as much of a increase as the TPS AE table.

 

this may be dumb thought but here goes.
with a carb the PS quantity is dependent on throttle position/rate of change in position. correct? no MAP sensor there! i dont see the need for AE/ MAP if we have AE TPS. i am sure GM had a good idea by bringing it into the function but i bet the car would run very fine just with AE TPS and the values set in AE MAP zeroed out. Or maybe a chip could be burned that way to see any effect it may have as a trial baloon for the fun of it.
another thought. possibly the AE TPS is the front 2/3 of PS and when it is used up the second 1/3 comes into play the MAP. MAP may take time to develop. that would be a function of time over which the PS occurs.

 

After several weeks, I finally got back to doin' some tunin'. I tried four more chip burns this week with 45%, 60%, 70% & 80% increases in the PS vs. Diff TPS table, as well as an updated main fuel table on each burn (the same one). I could feel the bog decreasing with each increase, but I'm still not where I need to be. It pulls pretty strong between gears once I'm out of 1st, but the engine still sputters and tries to die after a launch in 1st gear. I'm going to try increases of 90-120% next...thank goodness for multiple chips. Also, thanks go to Ronny for keeping me from being too timid with these PS increases!

Oddly enough, I noticed my BLMs varying with the different chips. I have attached BLM summaries of the 70% and 80% chips...you can see that the engine ran richer with the 70% burn. Dunno on that one...regardless, my BLMs are ranging from 125-133 now. Is this about the best you can expect, or should I attempt to get closer to 128?

Also, I'm finally ready to order all my fuel line junk from Summit. I'm going with braided stainless steel like Z28 Boy did (check out his web site at http://z28boy.cz28.com/main.htm and click on MODS and then FUEL LINES), so it's gonna run me about $200 including the fuel pressure gauge. I think I'm just going to get a little NPT fitting to tie a rubber hose into the gauge fitting temporarily so that I can tape it to the cowl and watch it while I drive. I'm pretty sure that I'll be getting my MAX fuel pressure since I'm running a 454 spring that is made to hold 30 psi on a fuel pump that can probably only put out 20 psi, if that. However, based on what Brent & Ronny have said, that still just ain't gonna be enough at WOT. Is there any way for me to objectively determine whether I'm lean at WOT? I didn't know if I could use WinALDL for upper RPM analysis or not. I know that the "old school" guys pull a spark plug and look to see if it's white, which indicates a lean condition...but that's a pretty primitive approach that requires trial and error.

Anyway, all thoughts or comments are welcome as always.

 

454 SPRING? NOT SURE IF ANONE IS USING THAT BUT? Be aware there is another spring sold by TDS and it is probably 1/2 way between stock and 454. on my 454 TB(not installed yet) i replaced the stock with an aeromotive FPG and will set to 12 lbs the day installed. now i have stock spring/ FPR as well. with 90 lb injectors i was able to get fuel tables in line including 3200. 3600 i tried but was difficult as i had to disable PE for that rpm. i think i got a few 3600 down and just fudged the rest. since fuel tables were in line the PE turned out perfect. commanded 12/1 was 12/1 on WB dyno. i rolled the dice on that and the puter did a fine job on PE ! OBTW i was never successful getting 128 across the board. i range from 132-124. most 126-130. a few outside will pop up and those always puzzle me as i thought i had them all adjusted closer than that. the AE may affect blm short term. not sure. i see the effect in my 02 V about a 1/2 second later.

 

Hey, Ronny...thanks for the reply. I know this thread has turned into a book, but earlier on I had problems with a lean condition and Brent recommended that I swap my 305 pressure regulator spring back to the 454 spring to pump up my fuel pressure since my 1995 454 TBI apparently is equipped with 68 pph injectors instead of the 80-90 that were on the 93-94 models. I may end up having to upgrade to the 90 pph injectors if I determine that I'm lean @ WOT...I just don't quite know how to do that at this point.

The only problem I think I would encounter with the 454 spring is if I need to crank down the pressure for some reason...I wouldn't be surprised if the 454 spring was higher than 20 psi @ its lowest setting.

I've seen you mention setting the Power Enrichment to 12.5:1 and 12:1 in your posts...I assume you're referring to the Air/Fuel Ratio, but exactly what do you mean and how do you adjust it? Is 12:1 the goal? I thought it was 14.7:1...anyway, your thoughts?

One more thing...Brent, I forgot to ask you about how to "dial in" the spark advance. You had mentioned this before in regards to increasing my fuel mileage...exactly how do I go about doing that? Is there another logical "next step" I should take instead of worrying with spark advance?

Edit: I also forgot to ask if I should include the 0% pump shot values in my % increases...so far, I have left it at the factory value while only increasing the 3.1-12.5% values. I figured that Brent told me to leave the 0% value alone because it could cause the car to run rich @ idle, but I just wanted to be sure.

 

Looks like you've got much of the VE table ironed out. The difference in BLM between the 70% and 80% is probably due to differing operating conditions (air temp, coolant temp, etc). Its nothing to worry about. IMO it's better to stay under 128 on the BLMs especially in the high KPA areas. How close you want to get to 128 is your call.

You might want to try increasing the MAP AE to cure the 1st gear stumble if you haven't already.

Set the fuel pressure high enough that it should be overly rich and make a couple passes at the track to get a baseline MPH. Then lower the FP a bit and make some more passes. If the MPH improved you know for sure it was too rich. Keep testing and lowering the FP until it starts slowing down at which point you'll go back to the fastest FP setting. If the MPH gets Worse after your first FP reduction its too lean and wants more pressure.

OR Set the fuel pressure high enough that it should be overly rich and head over to the local chassis dyno and make a pass with their wideband O2 and that will give you an idea of how rich or lean it is. After this, you can head to the track and dial it in for the the best MPH.

It all comes back to finding out what pressure the pump is developing at WOT. 30psi is absolute minimum I would start with for WOT testing.

The PE air/fuel ratios are in their own table. They are richer than 14.7:1 as thats only for part throttle and emmissions. I wouldn't mess with them just yet.

Spark advance at part throttle is about incrementing the timing until the engine runs at the least TPS or KPA for a given RPM, MPH and load.

For example:
Find a flat stretch of highway and drive it at 2000RPM and whatever gear that just keeps up with traffic (60-70mph?). Keep the TPS as steady as possible. Datalog this run. When you get back, note the TPS and MAP the engine runs at. If it cruises at 50KPA @ 2000rpm then increase the timing 2 degrees from 30-50KPA in the 2000RPM row. Burn more proms each with an increase of 2 degrees over the last one. Take them all out to the same stretch of highway and see which one results in the least TPS and MAP to run 2000RPM in the same gear as before. Its key to run the same strip of road because you want the same load on the engine every time.

Once you get past optimum you'll start needing more TPS or the engine will start detonating. You may not even get past optimum before it starts detonating.

Regarding the 0% TPS AE, I think that this value is always added to the fuel calculation, so increasing it will add fuel to everything. This could be completely false but it sticks in my head for some reason.

 

was anyone able to confirm your injectors as 68 lbs?? i want to believe they are 68 lbs as that makes sense for 454 at 28 lbs FP. GM dealer read the 94-95 truck runs 26-32 lbs FP so that spring pressure preset at factory should be right their. that will fuel a 454 cid engine at operating rpm which i assume is about 4300-4500 rpms. but at idle you engine is much smaller in CID so i would think you are very rich at idle and daily driving. that is unless you have set the BPW accordingly and worked on the fuel tables. i assume that has been accomplished.

 

OK...question time. I'll start with the pump shot issue. Brent, you mentioned that I may want to consider increasing the MAP AE in addition to the TPS AE. This leads me to two questions for Ronny:

1) Did you apply the same multiplier to both the TPS & MAP AE tables as you eventually increased your pump shot to 250% over stock?

2) Did you include the 0% TPS and 0% kPa pump shot values in your increases?

Next topic: dialing-in the spark table. Brent, thanks for the advice...I just want to know if I should follow this same procedure for engine speeds other than 2000 rpm, or is that the only load I should focus on now? I mean, should I run the car at multiples of 100 rpm for the 1600-3600 rpm range (and possibly higher MAP) and apply the same logic? Also, are the values in the Main Spark vs. RPM vs. Load table the actual timing values? For example, I have a value of 37.97 @ 2000 rpm and 30 KPa...is that 37.97 degrees of timing? One more thing...since this table is based on load, will my change to 3.73 gears throw a wrench in the works since the engine loading would be different (...or would it?)?

And lastly: my fuel pressure issue. I'm definitely going to document my current fuel pressure from my stock fuel pump, but I'm getting the feeling that I'm destined for failure because I haven't heard anyone getting greater than 20 psi out of their stock L03 fuel pump. Brent, here's a quote from way earlier in this thread:

Sounds like I may need to go ahead and accept the fact that I will need to invest in a Walbro fuel pump (for the ability to reliably hit 30 psi), 17112560 injectors, and the experience of dropping my fuel tank (or paying $$$ to get someone else). I know I'm putting the cart before the horse since I haven't documented my current fuel pressure...but I'm just trying to be realistic (and prepare myself for spending even more $$$ ).

Sorry for all the questions and writing a book...just tryin' to learn as much as I can from the best. :hail:

 

Pump shot: IIRC Ronny was/is running a crossram/crossfire type intake which will have different AE requirements. What worked for him won't nessesarily work for you. The best thing is to test and not get locked into thinking a certain number will work.

Spark: By all means test and tune every row (RPM) in the Main Spark table. 2000rpm just popped into my head because many overdrive tranny's cruise on the highway near this RPM. The rows increment in 200rpm steps. Its best to use 4th,5th and 6th gears, where possible, for testing. Don't get a ticket testing the 3600rpm row. lol

The values in the main spark tables are NOT the actual timing. There are other variables that are added and subtracted from those numbers. It really doesn't matter though. Tuning isn't about the numbers so much as its about having a reference. The 3.73's will probably change the amount of timing the engine will want, but since the 3.08's place a greater load than 3.73's I'd think you'll be ok. Meaning the 3.08's will require a more conservative timing map than the 3.73's. You'll just have to test it out!

Yeah, the stock fuel pump isn't up for high pressure operation. I've torn a TBI pump apart and its not a positive displacement pump. There are two rotors running in seperate cavities.

If the budget is tight you might try a hydraulics shop to see if they can bend/fab you some hard fuel lines, while reusing your stock fittings, rather than going the braded lines route Z28boy did.

 

since i just began tuning 7/2003 i was very conservative and wanted a documented/notetaking approach to tuning. i started with what i believed to be a stock calibration(what i was told) and as far as AE/TPS/MAP i added at first 5% each burn compounded to ALL tables not knowing the result. result was no result good or bad. i then moved to 10% and this was compounded on prior adjustments. net was about 250% of base tables tps and map and that is much better. that last burn was done 11/2003 and tested 4/2004. now i was of opinion that cold temps were dimishing the returns i was getting. i thought lack of atomization in cold xram pleum was an issue with AE and now same with choke function(4/2004). now BEN is running a 383 and he looked at 454 bins for AE and found the numbers very high for AE so he less reserved in going for big number on AE. I am removing plenum (454TB) maybe this week so all this will change and i may need to scale back on AE tables. another effect that i believe enters in is the ability to open a 2.00 in. TB immediately with a large influx of air and the delay B4 the TPS or MAP can catchup. add to that alck of atomization on cold plenum floor. i read the TPI cars may have a graduated throttle opening on cam? maybe holley does as well? that is a good idea. BUT maybe more AE at lower TPS and MAP can produce same result.

Aeroquip offerers push on rubber fuel line and i think rated to 1000 psi. with suitable reusable AQ fittings a very nice installation.

 

Well, two months and a newborn baby later, I'm going to try and do some more tunin' on my lifelong project Camaro. I already worked on it a little a couple of weekends ago...finally was able to move the CTS back to the front-left side of the intake as well as running a proper vacuum line for the A/C vent valve.

HOWEVER...while running the new vac line I discovered that I had an unplugged vacuum port on the front of my 454 TB! I have NO idea how long I had left it open...I may have done some data-logging with it like that. Anyway, I used the open port for my A/C, which fixed the problem...but now my car is running even worse. Much worse.

Of course, the car didn't run that great before...as you know, I've been struggling with a "bog" problem. However, the bog is like twice as bad now that I have capped off that open vacuum port. Here's my guess as to why this happened...I effectively decreased the A/F ratio when I plugged the port, which now causes the engine to run richer. Maybe I need to go back to square one with my pump shot increases and start over...or maybe not. I just don't know the difference between a bog caused by too little fuel and one due to too much fuel.

Any thoughts? I plan on doing some more data-logging tonight to see how my BLMs look as well as to gauge whether moving the CTS made a difference or not.

 

wow i thought i was the only one to do somethin like that. i would think it would act as an open additional IAC. off idle not sure if the small diameter tube would lend much additional air volume? was your idle speed high as result ? mine is a bit high but with the AC on and the one IAC dead and seated not too bad. commanded idle 700 but 800-850.

 

Been a while, Ronny...yeah, I was running high on idle before. The engine definitely idles better now (750 rpm), but the weather is warmer now as well...the true test will be when winter rolls around again.

So, you don't think that little vacuum line (about 1/8" in diameter) would matter much above idle? I wasn't sure...you're probably right, though.

I ran a couple of test runs tonight and found that after moving the CTS, the coolant temp went from reading 20-30F below the gauge reading to 20-30F above the gauge. I imagine that it is accurate now, considering the coolant temp was ranging between 185-195F and I'm now running a 180F thermostat. Of course, now it looks like I need a new coolant temp sending unit for my temp gauge.

I tried running a chip with 120% increase in PS vs. TPS and 25% increase in PS vs. MAP tonight and I think it made an improvement...but I'm not sure. My "seat of the pants-o-meter" hasn't been calibrated lately (ha), though. The car still coughs and sputters when I do "spirited" takeoffs from a standstill. I know this may indicate that I'm maxed-out on fuel pressure, but I'm going to go ahead and try adding some more pump shot to verify it...I'll post when I get the data.

 

Congrats on the new arrival. Bet that's alotta work! Sleep much?

I had an unplugged vacuum port on the front of my 454 TB!
HA! I think you posted a pic of it earlier in this thread.

I suspect the increase in the indicated temp caused the ECM to reduce the warmup advance. Generally, in the lower temp regions of the 'Coolant vs Timing' table there is timing added. Once you hit operating temp the table adds zero timing.

This may indicate the engine wants more timing but only testing will tell you for sure.

 

Yep, it was the same port...but I don't know what happened 'cause I plugged it back up the night I took that picture! I guess I pulled the hose off again while doing something else...

Anyway, that's a good point about the ECM seeing a higher indicated coolant temp...I had just assumed that the car was running worse due to the now-plugged vacuum line. Sounds like I need to get crackin' on tuning my spark table...

 

all i can say is that i ended up 250% higher than what i believe to be stock bin for AE/TPS/MAP and i suspect that is not enough. if i load car heavily in first gear. like get car rolling in first 5 mph and then mash it. cough and go with me backing off on gas or i am certain it would die or buck bad.. i will go more AE BUT since my mods changing soon have not been tuning.

 

Well, the skies parted, the sun shined down, and the good Lord blessed my poor 'ol Camaro.

My car now runs like MAD and pulls incredibly hard...at least compared to the pathetic state it was in before. Wanna know what I did?

I kinda hate to admit it, but remember when I was foolin' around with my "EGR On Temp" value? I had set it to 01 in hex, which actually correlates to 1 degree F...it was ALWAYS on! I changed it back to 254 mph (hex=FE) and I think that is what did the trick.

The reason I'm not positive that was the problem is that I made a few other changes at the same time. JPrevost advised me to change the main spark bias to 0, apply a 1.5 multiplier for both pump shot tables, and use the LT1 spark table (these are changes he did for his 350 HO/Holley TBI combo). I wasn't able to get my hands on a $DA mask to read the LT1 spark table, so I just used a stock ANLU table instead. And Brent, I still intend to go through the spark table and increase timing using the least TPS and MAP as you recommended.

Now I need to verify that I can support WOT runs...just got to get off my rear and install my fuel pressure gauge (I've been planning to for MONTHS).

The funny thing is that I wasn't 3 minutes into my victory test drive when I got pulled over for speeding! Fortunately for me, the officer ended up living one street over from me in my subdivision and let me go...VERY cool. He had seen me working on my car for months and I explained to him that I was just a little too excited about finally getting the chip tuned properly.

Words cannot express how ecstatic I am right now...it's been almost one full year since I did the swap and I just now have it running smoothly. One area of concern, though...has anyone ever had WinALDL go crazy on you? I've never had trouble with it, but today it kept stopping and starting on datalogging. Sometimes, it would blink red at the top of the window instead of green, at which time it would just start streaming random data across the data table. It seemed to mainly mess up under acceleration. Any thoughts?

EDIT: I forgot to mention that I messed up and forgot to disconnect the battery power when I pulled one of the chips out; however, I did disconnect it prior to installing a chip back in the ECM. Isn't the chip the only thing at risk when you do that? IOW, would the ECM have been damaged? I just don't think that's the case because the car ran great and I got no error codes.

 

I'm glad performance picked up for you.

The EGR ON Temp should be set to 01 not 254. 01 is not 1F. Remember the 8746 uses inverse temps. Look at a datalog in the RAW Coolant Temp column and you'll see how the numbers decrease as the engine heats up.

Did I read correctly that you reduced the Main Spark Bias from 20° to 0°?

That adds 20° of timing to the whole curve. You may want to double check with him on that. I can't believe he'd recommend THAT much timing. That'll put your timing against the 40° limit at part throttle and WOT with the slope and PE adders.

You probably want to disconnect the ESC wire and double check your inital Timing to verify that its still at 10°. Once you reconnect it and restart you should see 35° advance at hot idle with the changes you mentioned.

I've only been playing with winaldl alittle while and so far I haven't had any strange data.

I don't know about the chip/ECM damage. If its working don't worry about it.

 

To avoid the risk of mis-quoting Jon, I don't think he'd mind if I posted his message he sent to me:

Brent, I had no idea that making that change to the main spark bias would have that impact. I guess that's an inverse constant as well, since a reduction of 20° actually added 20° timing to the whole curve. Jon referenced the "main SA bias value" (see above), which I assumed meant the main spark advance bias...maybe he was talking about a different constant. I see some other constants in the mask, such as Max SA, Min SA, Max RPM for slope SA, ALDL SA and MAX SA for EGR. Jon, could you chime in here?

As for the EGR On Temp...maybe that wasn't what made the big performance difference after all. I looked at a datalog like you recommended and I see what you mean...a reduction in the raw values results in an increase in the calculated coolant temp. I actually already have a chip burned where the only difference is that I left the EGR On Temp to 1 (calculated) or 01 (hex)...I can pop it in and see what happens.

 

I wouldn't call it inverse exactly. The 'Main Spark Bias' value is subtracted from the total timing calculation. Its purpose is to make negative values possible in the 'Main Spark Table'.

I looked at some allegedly stock LT1 files and many have atleast 30° if not more, in the WOT parts of the table. When you add in the slope and PE spark adders you end up with 35-40° of WOT timing. Not exaclty a nice conservative place to start tuning.

The problem with cut and pasting as I see it, is one gets thinking on the wrong track. You get focused on numbers instead of performance. And if you're missing a particular value or adder you can have way more timing than you thought which can lead to engine damage. IMHO its best to start from too little timing and move up in small increments.

 

Yeah...sounds like I may have jumped the gun regarding the spark table. I was just really encouraged when the car ran SO well...but I definitely don't want to risk engine damage! Is it possible to tell from a datalog whether or not the timing is advanced too much? I sure hope I haven't already done some irreversible damage to my "practically new" engine.

However, I never did use the LT1 spark table because I could'nt get my hands on the right mask...I used the ANLU (Caprice Police Interceptor) spark table instead since it was for a 350 and it uses the same mask as my AXKW bin. I think it is actually a little bit more conservative than the LT1 version...I'll post a screenshot when I get home.

A friend of mine is going to let me borrow his timing light to verify everything...how did you determine that it would run @ 35° advance @ idle with the ESC plugged in? I'm guessing that's 10° initial timing + value @ idle rpm in the main spark table + some other stuff?

EDIT: I just did a search and found a really good article on detonation here. Sounds like I definitely may have already damaged the pistons/rings/etc...I'd better dump some octane boost in my tank before I drive the car home with that chip. The article also said to monitor the engine knocks to determine the amount of detonation...guess that answers my question about how to use the datalog to analyze the effect of the timing advance. What units are used for knock counts? The article says that it picks up sounds @ 6400 Hz, so is it the duration of the knock?

 

Brent, I have attached a screenshot of the ANLU spark table. I did a comparison and it doesn't look all that different...it adds a little over most of the table and actually pulls some out in the upper right-hand corner of the table. This table was made to work for a much more docile 350, so I'm guessing it's OK to keep it.

Here's what I'm going to try...let me know if this is a good idea. I'm going to burn a new chip with the same ANLU spark table, but setting the main spark bias back to 20.04°. I'm going to change the EGR on temp back to 1 as well. I will then be VERY curious to see how the car runs compared to before.

Assuming it runs OK, I'll go ahead and go through the spark table and slowly add timing until I determine which setting results in the least TPS and MAP to run the same rpm.

Brent, could you give me the formula for calculating the engine timing? I know it's based on all the variables we've been talking about...I just don't know exactly how the variables impact the timing. I think that would really help me understand what's going on with the spark table...thanks

 

how did you determine that it would run @ 35° advance @ idle with the ESC plugged in?

I just looked at the idle region of 'Main Spark vs RPM...'.

With the 'Main Spark Bias' zeroed, you get whats shown in 'Main Spark VS RPM...' plus or minus temp corrections and probably some other stuff that I can't remember. But its pretty durn close to what 'Main Spark vs RPM' shows. When I've put a timing light on a car they have been within 2-3 degrees of 'Main Spark vs RPM..' minus 'Main Spark Bias' just running the car in the garage.

Once you exceed 3600rpm the Slope value is added. Once you hit PE mode additional timing is added. EGR and hiway modes affect timing also.

Is it possible to tell from a datalog whether or not the timing is advanced too much

Maybe. You might get some knock counts. Might not. Its not something you want to bet your engine on.

I will then be VERY curious to see how the car runs compared to before.

Rest assured, it'll be a dog again until you've gotten the proper timing dialed in.

Brent, could you give me the formula for calculating the engine timing? I

http://www.diy-efi.org/gmecm/papers/747spark.txt

I know its for the 7747 but it gets you the general idea.

 

Thanks for the insight, Brent. I scanned over that article and it appears to be just what I was looking for.

You know, this whole experience has at least given me some inspiration because I now know that my car CAN run smoothly...I honestly had no idea that the spark table was the reason behind my car running so poorly. I thought that changing it would just help me get better gas mileage! I'm such a dufus (ha)

Anyway, just to be sure, should I use the ANLU spark table as my starting point or revert to the stock AXKW table?

 

The ANLU timing chart posted a few up is not correct. Each location needs to have the main spark bias subtracted from it. In ANLU that value is 20 degrees. As such it will make a huge difference in the actual timing (Like 9 deg at 3600 RPM/100 KPa vs. 29 deg as shown).

If the heads on the 350 HO engine are the the Vortec iron head then I too recommend that you start with the LT1 iron headed SA table. Knock a few degrees off at the high load column and give it a go.

The table has been posted here sometime since the beginning of the year.

RBob.

 

Now it's starting to make sense as to why Jon told me to set the main spark bias to zero and use the LT1 spark table...the LT1 table values are already lower because they assume a zero main spark bias! I just thought that I could use the ANLU spark table in place of the LT1 table, assuming that they were both built with the same logic. Oh, well...live and learn.

Man, it is an absolute miracle that I didn't destroy my engine...I sure hope I haven't done any permanent damage, like pitted the pistons or messed up my oil rings. I probably need to put in a new set of spark plugs because I read that detonation can do a lot of damage to them.

Edit: RBob - I found where you posted an iron-headed vortec spark table here. Is that what you are talking about? If so, why are the axes swapped?

 

That's the one. Because I like being different

RBob.

 

...LT1 iron headed SA table...

Ah! I looked at f-body tables which have more advance in general. The 33° at WOT looked like a potental trouble maker when the slope and PE adders in AKXW hit.

 

Brent, do you mean that you agree with using the iron-headed Vorted SA table as a starting point? (see attached) Didn't quite understand what you meant...

RBob, please take a look at the attached table...it's exactly like the one you posted, except I did as Jon Prevost recommended and increased everything below 12° up to 12° in the high kpa/low rpm area of the table. You mentioned knocking a few degrees off the high load column...do you mean just the 100 KPa column? If so, do I just take 3° from each value in that one column? Also, I assume I should set my main spark bias to zero if I use this table...right?

Once I nail down my starting point, I need to start tuning the spark table as Brent recommended:

I know I'm beating this to death, but I just want to make sure I know what I'm doing after my recent fiasco. Brent, should I increase my timing 2° across the board and datalog at each RPM/KPa level in the spark table? I suppose I would then analyze each cell and determine whether I need to add 2° more timing or put it back where it was. IOW, should I try to tune the entire table at once, or only take one RPM/KPa cell at a time? I sure hope not...that would take forever .

Thanks for hanging in here with me, guys...your help is much appreciated, as always.

 

I'd go with Rbob's suggestion. He's without a doubt the code master.

LIke Rbob mentions I'd reduce the 2800-3600 X 95-100KPA cells to 24°. With the PE and Slope Adders this will give you approx 31° at WOT. This is on the conservative side, but IMHO you want to move from less to more while making sure performance increases. Not to mention we don't know if your harmonic balancer timing marks and/or your timing light are off by a couple degrees.

should I increase my timing 2° across the board

No. You need a baseline first. Get out there with the iron LT1 table and datalog it at some highway speeds. See what TPS and KPA are required to run a particular stretch of road.

should I try to tune the entire table at once,

Absolutely not. Just worry about the normal highway speeds for now.

Using your table above for illustrative purposes:

Let say you find in your datalog that your car runs steady at 60KPA, 15 TPS at 1800rpm and 60-65mph. So you increase the 1800 X 60kpa cell from 28.5° to 30.5° and any cells in the 1800-3600 X 35-60 area that are less than 30.5 get increased to 30.5°.
Burn that chip.
Burn another chip with the same process only using 2° more. (1800 X 60 will be 32.5° etc.

Go out and datalog at the same place,rpm, mph with each chip. If the first chip results in MAP of 57kpa, 13 TPS at 1800 rpm you are headed in the right direction. If the second chip runs at 55kpa and 11 TPS you won't want to increase the 60kpa column anymore, just work on 55kpa and less.

If you've advanced the timing 4° and nothing is happening go back to the stock iron LT1 table and remove 4° to see what happens.

Keep your eye out for knock counts and plug reading wouldn't be a bad idea.

 

Thanks for clearing that up, Brent...quick question, though. My baseline datalog with the new LT1 spark table indicated that I still needed to make some small adjustments to the fuel table. Should I run another datalog after I adjust the fuel table before I make any spark table changes?

One more thing...I had a value of "1" for every record in my spark count column in my datalog with the LT1 table except for one towards the end that had an "8". Is that anything to be concerned about? Does it retain a spark count throughout the datalog once it records one? FYI - I had a spark count of "12" in the datalog from when I was running my "extremely-advanced" spark table.

 

Should I run another datalog after I adjust th....

Can't hurt. I'd compare the two logs just to see if anything sticks out.

The knock counter increments when knock is detected (this doesn't mean that all knock is detected by the system). Once it hits 255 it resets to 0 and starts over.

You may get some knock counts on startup. That seems to be common.

If you repeatedly get counts at a particular RPM and KPA then you want to look into that.

 

OK...need some guidance here.

Take a look at these two datalogs:

Baseline datalog

Modified spark table datalog

The first datalog is the baseline with the stock iron-headed LT1 spark table, while the second one is the datalog where I added 2 degrees of timing @ 2000 rpm and 45 kPa because I was running about 43 kPa and 1950 rpm @ 60 mph. I found it difficult to hold the pedal perfectly still to maintain a certain TPS, but here's an average summary of the two runs:

6/20/04 - baseline
MAP RPM TPS Gear Speed
41.8 1938 5.3 5th 59.8

6/23/04 - modified spark table
MAP RPM TPS Gear Speed
41.5 1940 5.3 5th 59.9

My kPa dropped slightly, so I guess I should charge forward with adding timing...right? I'm just not sure if I've got clear enough data to make a good judgment call here. Also, my datalogs keep getting messed up (as you can see)...I'll get a bunch of lines of random data with lots of zeroes, followed by good data, then back again. I'm also getting a few spark counts, but I don't know if it's anything to be concerned about. Lastly, I'm still battling some lean areas in my fuel table...I'll add fuel, but it doesn't make much of an impact.

Just in case anyone would like to see it, here is my bin.

Any thoughts?

 

Add another 2° and see what your results are. If you aren't comfortable with that, go back to the stock LT1 table and pull out say 8-10° in the 1600-3600 x 35-55kpa area and see what your results are.

At 40kpa the engine is hardly working so it might be tough to find small power increases. You sure that wasn't a down hill grade?

Perhaps you should use 6th gear to place a larger load on the engine. Maybe try 1600rpm.

Just like with the BLM's you'll have to mess around until you can get a feel for it.

The only place I saw the knock counts increase was when the engine got pulled down to 550rpm @ 96kpa.

 

I see what you mean about the data log mess. Have you changed anything in the way you hook up your laptop? Are you using the cars electrical system to power the laptop?

A thought on the IAC: With the larger throttle plates in the 454 throttlebody you don't have to open them far to get a bunch of power. I'd bet the throttle is like a switch almost. IN your datalog the IAC is open to its max of 80 counts at only 5% TPS. This might be letting enough air through that it will be tough to see TPS increases as you change timing around.

Rbob mentions a parameter, 'Throttle follower factor' that apparently reduces the rate at which the IAC opens compared to the TPS. Here is one of the posts.

 

Hey, thanks for the info on the throttle follower action...I think that is DEFINITELY a problem on my car. I can tell that the IAC just stays open WAY too long...every time I come to a stop, my engine takes several seconds to go from 1500-2000 rpm back down to 750 rpm. In fact, I can even totally let off the gas in 5th gear and the car will maintain 50 mph for quite some time before the IAC starts to close (I guess that's what's happening, anyway). I don't have TunerPro in front of me, but the thread you referenced makes it sound like I can adjust some of these throttle follower terms in the constants in my bins...I've just got to figure out what to change them to. The thread indicates that I should reduce the TF factors so that the IAC will move less relative to the TPS. Looks like I should also try to increase one or all of the three filter coefficients so that the TF steps will decay faster when I lift off the throttle.

As for the datalog issue, I've been using 12V from my car since day one...that was the only way I could get the laptop to work. I think it has a weak battery that just didn't provide enough excitation voltage or something. I'll double-check my power connection...maybe it's loose or something.

Also, sounds like I may need to head out on the interstate to do my spark table datalogging...I think my car does about 70 mph in 6th gear and 1600 rpm (3.08 gears...geez). I don't even normally use 6th because it bogs so bad. I actually was driving on a flat stretch of road for the two datalogs I listed...dunno why the engine was so lightly loaded.

 

dunno why the engine was so lightly loaded.

You've got a relatively light and aerodynamic car which doesn't need much power to run 60mph, well, compared to the old and busted, 4600lbs, air shoving cinder block that I've tried some of this stuff on. So part of it is my thinking in terms of trucks and not cars, meaning the numbers I threw out in the posts above.

There is a good possiblity that the LT1 Table is close enough to what you engine wants in much of the operating range that you will not find lower TPS and MAP readings by increasing timing. Or the gains may be so small that its hard to accurately measure. Reducing timing can show you which direction you should move without risking detonation. Either way test it out and see what it wants. Might be interesting to keep a log of fuel mileage too.

How does it run with the Lt1 table?

I dunno what's up with the datalogging. I have a 1 transistor cable that I plug into 12V at the fuseblock, Terminal E for data and A for Gnd and I run a AKM Max232 cable the uses E and A only. Both work the same. I only power the laptop with its internal battery as I've read that ground loops can occur when using a cig lighter to run the laptop.

 

I saw a marked improvement when I switched to the LT1 table...the car doesn't spit and sputter nearly as much, I definitely picked up some power, and my mileage increased from 15 mpg to 18 mpg. The mileage increase is actually probably even better than that...I sorta had my foot in it several times for that last tank of fuel.

However, it's obvious that I still have some tuning to do...the car still does not run very smoothly throughout the rpm range. I ran another test run last night, this time adding 2 more degrees. It impacted the spark table to a larger degree this time because I not only increased the value @ 2000 rpm and 45 kPa, but also four other cells because they were lower than the first cell I changed. Here's a comparison of the results to my previous datalog:

6/23/04 - modified spark table, 2° of timing
MAP RPM TPS Gear Speed
41.5 1940 5.3 5th 59.9

6/24/04 - modified spark table, 4° of timing
MAP RPM TPS Gear Speed
40.4 1935 4.7 5th 59.7

As you can see, the MAP decreased as well as the TPS. I think the problem before was that I changed the 45 kPa/2000 rpm cell, when I should have started with the 40 kPa/2000 rpm cell (I increased it by 2° this time). SO, I'm going to continue with adding steps of 2° in timing and see if I keep decreasing kPa and TPS.

Also, I checked out my bin and all I could find regarding the throttle follower constants was location 538, which is the max TF steps (which is set @ 80). I couldn't find any of the other locations RBob listed...I wonder if he was referencing a 7747 or something. I found a constant @ location 532 labeled max IAC steps and it was set at 191 (calculated)...I don't see anything else in my mask with a TF in the title. I do see some constants referencing "dfco"...any idea what that is? Could these be the filter coefficients? They are in locations 270-277, by the way.

Of course, once I do identify these constants, I need to figure out exactly what changes need to be made to them. Time to do some diggin'...

One more thing...I collected some 6th gear/1600 rpm data last night as well. I ran 1600-1625 rpm at about 73-74 mph, but my kPa varied from 43.6 to 58.7 and my TPS varied from 2.6 to 8.4. I obviously need to try that one again with a little bit steadier foot on the pedal and a more consistently sloping road.

 

i have been watching my IAC steps. It would appear they are at zero and hold there once the coolant temp is up to the amount in constants. i dont think my iac's move much at that point. deaccell enlean was removed as engine would kill on long deaccell. with air on of course they move. why would they move if engine closed loop? i understand the function of iac somewhat well. what is function of throttle follower? i do not see it in tunnercat but assume i could get it added. 7747.

 

I sorta had my foot in it several times for that last tank of fuel.

I hear that! I just bought another ride and it rows through the gears so nice I find myself speeding much more than normal.

40.4 1935 4.7 5th 59.7

Looks like you are heading in the right direction. Don't forget there is a 40° limit in AXKW, so once you get there you won't get anymore advance.

I couldn't find any of the other locations RBob listed...

He mentions those addresses are for the 8746. The copy of 8746 ECU I have has some of the TF stuff. I don't remember if I put it there or if thats the way I got it. Its in your email. Double check it against the info he posted.

I'd probably try reducing the value at 543 first and then 542 to see if one of those reduces the rate of IAC opening.

DFCO is Decel Fuel CutOff.


Ronny: IAC Info

 

Thanks for the ecu, Brent...I see that it has locations 540-543 mapped as constants. I attempted to add locations 53A-F as outlined by RBob, but I quickly realized that I didn't quite know what I was doing. I know what to enter for the "Start Address" (obviously), but I don't know what to enter for the offset, operation, factor, etc. Of course, I may not even need to mess with those settings...I'll play with 542 and 543 first as you recommended.

As for using the ALDL ecu to datalog spark advance...I'm sortof at a loss on that one. I read through everything, but I don't understand how making changes to an ecu file has an impact on what WinALDL will datalog...what's the connection? Jon gives the following example in the help file:

I assume that the "bin file to edit" is any datalog text file from WinALDL...but I don't see how making changes to a previous datalog has any impact on future datalogs. I know I must be missing something...I also tried to change the constant for #15 as in the example, but I don't see anything in the ECU editor where you can change the location (doesn't show "0040" anywhere). I'm also confused on the values I got for the constants...Jon says to display the data in hex, but I don't know what I'm looking at (see below).

Oh, thanks for the reminder on the 40° spark advance limit...I assume that I need to leave that max value alone, right? It probably wouldn't be safe to go above 40°, even if the datalogs were indicating the engine wanted more advance.

Now about this new ride of yours...tell me more! Thirdgen? Or another "old and busted, 4600lbs, air shoving cinder block"?

You kill me, Brent...

 

but I don't know what to enter for the offset, operation, factor, etc.

The purpose of that stuff is to deliver human readable numbers. The ECM 'operates' in hex (00-FF). Hex converts to/is the same as decimal (0-255). Er... I'm having trouble explaining this. Anyhow, As far as I can tell, the only location between 538-543 that requires an entry in the 'factor' field is 541, 'TF %TPS Bias'. That factor should be 0.392157. The rest only require the 'Start Address' and the 'Map Name'. Leave the other fields alone.

As for using the ALDL ecu to datalog spark advance...

What you are doing is loading your current AXKW bin file in Tunerpro. Then you'll open the 8746 ecu include in that zip file. That ecu file allows you to edit the ALDL locations in your AXKW bin. These locations simply change what data (spark advance, battery voltage, MAP, RPM, etc) the ECM is sending Winaldl.

Now that you are viewing your current AXKW with the ALDL ecu you'll change '1. eprom id lsb' from D002 to 0061 and '2. eprom id msb' from D003 to 0062. Make sure you are viewing in Raw Hex. Save your bin and you're done.

Now Winaldl will log spark advance in the 'Sensor: PROMID' field. When you open the datalog in Excel, insert a new column next to 'Sensor: PROMID' and call it 'Spark Advance'. Enter the following formula in each cell in the new column: ='Sensor: PROMID' * .352 + 'initial spark adv', where 'initial spark advance' = 9.84 in your case.

Whatever you did to to get the numbers shown in that picture, get rid of those files and start with new copies of your latest bin and the aldl ecu.

advance limit...I assume that I need to leave that max value alone, right? It probably wouldn't be safe to go above 40°, even if the datalogs were indicating the engine wanted more advance.

I don't know if its safe to change the advance limit. Its based in the physical limitation of the distributor. At part throttle the engine may want more than 40° in some of the very light load, higher rpm areas and it may be quite safe. My worry about 40° before (ANLU) was because it was at such low RPM's and higher load areas.

Now about this new ride of yours...tell me more!

Ahh, sorry that information is classified! I can reveal that it is not another fuel guzzling truck.