Hello fellow TBI users,

I need some help with tuning here. Im still learning but you can never seem to learn enough to get things where you want them, and then when that happens, we make a change to the motor. haha.

So im tuning with the EBL Flash and i wanted to see what some thought of my VE table along with my spark table. It was originally super high but I have recently brought it down.

Pics to follow

Thanks!!

Update: Found the problem with the crazy VE tables. Wrong Base Calibration...Duhhh

 

Updated Tables:





Vehicle Information:
1991 C1500 Single Cab Short Bed
5.7 350 (Bored 30 over)
Stock LO5 Swirlport Heads
Comp Camshaft(212 218 112LSA .449 .456)
65lb/hr Cop Injectors running at 12psi(Soon to be increased to 20)...Now Running 65lb@25PSI(90.1)(as of 12/20/2011)
Hedman Headers
2.5 Dual Delta Flowmasters though X pipe( Soon to be changed to 14" Magnaflow with 2.25 inch piping)
Ultimate TBI mods including TB Spacer and Injector Spacer
14" K&N Open Element
Edelbrock Performer Intake
Underdrive pulleys


I'm running about 80DC at 4k and ive seen it go to 100% in the past at about 4K. Its definitely running out of fuel and I can only imagine whats gonna happen after refueling it since its been running like this since about 2007 when i changed the 55lb/hr to these(not a huge help).

 

See above

 

Can someone take a look at my SA tables and tell me if i should smooth them out in the "rigid" areas or should they stay "rigid" like that? I am not sure how to tune the SA tables best. Thanks!

 

Any thoughts?

 

The SA tables are based on LO5 truck calibration. One possible reason for these peaks (non smooth ) is emission control - mandated by EPA (or CARB) emission limits. Another possibility is that these tables were optimized for stock exhaust system which has some back pressure. When you swapped in a cam and exhaust it is a whole new ball game - engine can 'breathe' easier and can take a little bit more timing, but do not get carried away. Too much timing is bad - you can really hurt things. Creep up 2 to 3 deg at the time and monitor KS for increased ping counts. It is best to be 2 deg below max - for optimum performance.
You did not mention in engine build up about heads, but a stock LO5 will have swirl heads ('182) which do not need too much timing - your maximum timing is around 32 deg at light throttle cruse (30 to 50 kPa). At WOT (90 to 100 kPa area) SA should be conservative - mixture is rich (12.8:1)and it burns fast (if you have enough fuel)! At light throttle fuel mixture either stoich (14.7:1) or if in H-cruse (>14.7:1) needs more timing since lean fuel mixture burns slower.

You can try smoothing out SA peaks and valleys - this easy to do with EBL, TunerPro, but you'll need to keep track of data logs and performance.

Bumping FP to 20 PSI is the right approach - do not forget to change BPC vs. VAC table to reflect this (use excel to calculate new BPC). At idle keep an eye on injector PW if it close to 1.1 mSec - you have reached a limit of TBI injector. 1.3 to 1.6 mSec is doable.

//RF

 

I guess i was asking also if we are suppose to smooth the SA table but you answered that. Well after I add fuel sometime tomorrow with the FPR i will see what the PW looks like, change the BPC, and continue tuning. Thank you for the PW tip, that is really good to know. I'm guessing once it goes lower than that is when it doesn't allow the motor to idle properly due to the injectors being closed for too long because of the high PSI(large amounts of fuel at once)? Also, I am running the stock LO5 Swirl port heads. I'm looking to swap them out but i have to come up with the money so im using this time to learn the tuning process for when i do more mods. I plan to do heads first and then later down the road when i pull the motor apart i will likely machine the block for 383, roller motor......and when i build the tranny and rear end ill throw some boost at it

 

I've been wondering. Maybe you can put some input. Why is it that fuel is based of HP numbers and not torque numbers. Does this mean that max torque may be achieved due to it being at 2k rpms or is that not the case? I wonder because peak HP(about 285) is seen on DD2000 at about 4500rpms while peak Torque(383Ft/Lbs) is seen at 2000rpms. I dont recall reading anything on this but some light upon this topic would be great.

Thanks again!!

Ulysses

 

RFmaster you were pretty much right on the money. It is running a little low on the PW. Sometimes it will dip down to .9-1.0 on DE or sometimes at a specific cruise speed even. It causes a slight notice but will go away upon more pedal. For the most part, it doesnt affect it much and will run around 1.3 so its pretty much maxed out.

I put it all together and it was running right at 25psi so i left it there for the night. I have been running and tuning it since last night. Its running great and definitely gets through the higher RPMs much better but its time for a WB and new heads, hehe. Actually I saw 90%DC at around 5100rpms. I didnt understand this as i thought i would have plenty of fuel up top! I for sure have the 65lb injectors due to part number lookup and im running at 25psi using a non liquid fuel pressure gauge. hmmmmmm

 

[QUOTEWhy is it that fuel is based of HP numbers and not torque numbers. Does this mean that max torque may be achieved due to it being at 2k rpms or is that not the case? I wonder because peak HP(about 285) is seen on DD2000 at about 4500rpms while peak Torque(383Ft/Lbs) is seen at 2000rpms.][/QUOTE]

that is a great question. Possibly RF will respond.

I think it has a lot to do with RPM 2000 vs 4500 rpms. The combustion chamber nneds to be filled with fuel in both case. Cept over a measure of time per sec the chamber needs to be filled 2X more often.

as a side note AE uses a lot of the DC% available as well. I see highest DC% in second gear of four(60mph?) where the load is actually less than 3 of 4 gear as speed is then >90 mph. same RPM.

 

Thank you for your reply. Yeah that question has got me in deep thought with nothing.

 

I have also had the same results looking at my datalog. I was in 2nd gear and the DC was much higher than I thought expected....around 90. It climbed to about 3700rpms in 3rd gear and then I quit there. It climbs so much better!!

 

Torque is force, horsepower (HP) is work being done.

Example: walk up to a solid stone/brick/cement wall, put both hands on it and push as hard as you can. There is torque involved as you are pushing on the wall.

But until that wall moves (not likely) there is no work being done. IOW, no HP is involved.

I still get a kick out of magazine articles (etc.) that state torque is what moves a car down the track. Nope, it is HP that moves a car. Because unless the car moves, there is no work being done and no HP involved.

Can be a bunch of torque involved, but once the car moves the work being done is measured in units of HP.

Another example (may require additional reading), why is it that NASCAR engines spin in excess of 9K RPM? Answer: to make HP.

RBob.

 

that is a great question. Possibly RF will respond.

I think it has a lot to do with RPM 2000 vs 4500 rpms. The combustion chamber nneds to be filled with fuel in both case. Cept over a measure of time per sec the chamber needs to be filled 2X more often.

as a side note AE uses a lot of the DC% available as well. I see highest DC% in second gear of four(60mph?) where the load is actually less than 3 of 4 gear as speed is then >90 mph. same RPM.[/quote]

I think it all comes down to a basic relationship between torque and horsepower. Just remember that the following formula applies for calculating horsepower from a torque measurement:

HP = (Torque (ft-lb) * RPM) /5252

In other words peak torque value may occur at low engine RPM - in your case around 2000 RPM, but it does not drop off very fast. Since engine RPM is another variable in HP equation it will push peak HP higher. At 5,252 rpm, the horsepower and torque values are always equal. That's why an engine's torque and horsepower curves always cross at 5,252. Another good thumb rule is that most street engines will have their peak torque RPM between 70 to 75% of the peak HP RPM point. If your peak RPM occurs at 4500 RPM your peak torque should be between 3150 and 3375 RPM - IFIK 2000 is a bit low something is off. But then DD is a simulation tool.

As engine RPM increase parasitic loses due to friction increase rapidly Since it takes energy to turn rotating assembly - more fuel is required...

//RF

 

Thanks for all the help! That makes a lot of sense now. It seems that I am getting a surge when i stomp on the throttle. It was there slightly but now it seems to be more noticeable. Any ideas? If i gradually raise the TPS it will be fine.

It runs great when at any given steady rpm and is now having trouble keeping a purring idle like it wants to but i think I am gonna have to reconfigure my fueling situation. I was thinking of going with 45lb injectors at a higher PSI. What are your thought of this? I know Fast355 is all about it. haha.

Also, I noticed something interesting arriving at the store today. I was rolling up the windows (there was always a drop in voltage with these heavy truck windows..haha) and the truck shut down in a split second. Didnt seem like a stall but like the injectors were lacking Voltage to keep that high of PSI. I turned it back on to test it again and sure enough it shut down as soon as i messed with the electric windows. Any thoughts?

Id also like to add that I have yet to do any kind of WOT learns or any tuning with a WB. Could this not allow me to have a smooth takeoff for the time being?

 

Acceleration enrichment (AE) and launch mode (LM). Can see what they are doing via a data log. If the WB is hooked up can use that to see if there is too much or not enough AE.

Check the data log (playback mode) to see if the ECM is losing power.

RBob.

 

Ok that makes sense because i noticed it smellled a little rich but didn't know if that could be it due to me running without cats, and it being WOT anyhow. Maybe im wrong. I looked at the tables and it does look to me as though there is a lot of AE fuel but i dont know enough to tell. Where should i start messing around?

 

Here are all my AE values from Tunerpro. Anything stand out that i could adjust or where i could possibly start. Im not that familiar with these tables quite yet. Any direction would be a great help. Thanks!

 

I see 65#/hr injectors at 25 psi, if that has changed change the following accordingly.

The injectors are now flowing 90 #/hr, stock being 61#/hr, so:

61 / 90 = 0.68

Highlight all entries in each the AE - MAP PW and AE - TPS PW tables and multiply them by 0.68

That will put the AE back in the ball park.

RBob.

 

Yes, I am running 65@25PSI so 90#/hr. I have made the changes and will give it a shot and reply later. That makes a whole lot of sense! Thanks!

Update: that seemed to make a good bit of a difference. I still can't stomp on the gas without a very slight surge. Its tiny, but its there. Could it have anything to do with the fact of me running such a short PW at idle? RFmaster was talking about the lowest at 1.3 and i see that quite often, and it will even dip down to .9-1.0 on a steady rev. However, when i was running 65lbers at 12psi it still had this bog down low but that was running the stock AE-PW(MAP&TPS) Parameters. I have to do some datalogs again to see whats going on.

 

The 1.3mSec PW at idle is not an absolute - it varies from injector to injector and operating fuel pressure. This is an area where you need WBO to figure out the root cause of surge. If your idle AFR is getting too lean because you are idling in close loop and when AFR swings above 14.7:1 the PW is getting too short and engine surges. You may want to consider to idle in OL and set AFR slightly rich - for example 14.3:1. This will require VE tables dialed in at idle. Also consider running fixed SA value at idle. IRC there are couple of posts in the main EBL thread how to do above.

//RF

 

So i pulled the Cop car injectors(65) and replaced them with the stock truck injectors(61). I also turned down the fuel pressure to 20psi. Off initial impressions at idle it is running soo much better. VE learns are adding 10-12% fuel at idle and other points when i bring the idle RPM up.

I feel that once i get it tuned up a little better, the surge will go away. It has been running at 1.6PWs now at idle. It sounds a lot meaner when i stomp the throttle and wants to just rev.

I can only imagine what this thing is gonna do once i swap out these swirl ports for something worth while. For now i will learn tuning and getting it ready for some Vortecs/AFR/Trick Flows. Im having a hard time deciding on heads because i want to keep EGR but also want to do it myself later down the road. For now i need to get the tune and some minor accesories(volts up for fuel pump, electric fans, WB).

 

Ok so im dumbfounded as to why i should be reading this high of a DC% Any ideas? Im running the 61lbers at 20psi which should put me right at 286 max HP with this setup. I cant be running more than 280 with a the cam(.449 .456 212 218 112lsa)/Edelbrock-3704intake/Ultimate TBI and full exhaust. I have read the PSI without fluctuation at all and is reading a solid 20psi.

Any Ideas?

 

Id like to add that this was a pull in second gear.

 

The BLM of 155 isn't helping. ECM was adding a lot of fuel before it went into PE mode. With the BLM that high it may be over fueling at WOT.

RBob.

 

[QUOTEQUOTEWhy is it that fuel is based of HP numbers and not torque numbers][/QUOTE]

That was RF on Q #2.. I think the need for fuel is also dependent on aerodynamic forces at higher MPH requiring more fuel. Probalbly exponentially 50 mph vs 100 mph.[

QUOTE]Yes, I am running 65@25PSI so 90#/hr. [/QUOTE]

That is a lot of fuel ! Are you running a VAFPR? It will clean up the idle PW being low as stated. As RF says I too use OL idle in fact OL <20 mph. I lock idle SA. And reduced the proportional gains. See my thread started last summer on PG regarding my DC% being high.

As RBob eloquently stated when in PE it reads the last BLM. If at 155(adding fuel) it uses it so as to not run excessively lean in pe. So it is apparent you are very heavy on fuel in CL just before it goes PE. 90 lbs / hour is a lot of fuel.

Post #17. Why is he at 5d SA in AE 92%TPS at 1050 rpms. Heavy truck?

 

Thanks for all the replys!

The 5 degrees could have been due to the short pedal stomp. It was in idle also. It is a single cab short bed c1500 but I don't believe its heavy enough to justify it being "heavy". They usually weight around 3800-4200. Id like to get the offical weight sometime.

Anyways, It has been running rich(says the BLMS) and showing high BLMS and the VE Learns are showing that as well adding 12%.

I will check out your post but don't have much of an idle problem anymore when i moved to 61lb injectors at 20SPSI.

 

Here is the main table. Someone was saying in another post that 16 degrees of timing was too little at 2000rpms with a map of 60. Im seeing differently on my WUD than whats going on here in the table. How is that so?

 

vafpr? if not worthy add on and relatively easy to install.

 

Im not quite sure on how to install one and dont have the wideband to see whats going on deeper with the AFR so i will put that off till then. For now i want to get use to tuning and help it run better. Its not having the low PW anymore when i changed the injectors and fuel pressure like stated. However I do believe i will not be able to get what i want up top but i need the WB to tune up there anyhow. For now i would like to focus on cruise and a good idle.

 

B4 I inversted in WB I did as you said. My VE was tuned well and on dyno with tailpipe sniffer I was commanted at 12.5 or 12.5 I forget and ran 12.0/1. so underlying will allow a good PE.

 

I am very interested in the SA discussion in this thread. I was wondering how the SA in the WUD logs is calculated for the EBL Flash. I am seeing different SA values in the log than what is in the SA table. For example at 2200 rpm and 40MAP I have 27* advance in the Tuner Pro SA table but am only showing a SA of 19* in my log with 0*retard. This is steady cruising at 54 mph with lean cruise disabled. I can look at my logs anywhere and what is displayed doesn't match what is in the main table. The log is always lower. Does someone know the formulas (which tables are used) to get the SA for the logs? I thought this was WYSIWYG but it doesn't appear to be that way. If I could understand how the log's displayed SA is calculated it would be easier to decide how and where to tweak the SA. Oh, and if it matters I have have base timing set at 10* mechanically and in TP.

 

SA:

Add together:

Main SA
PE SA
ALDL SA
EGR SA
IAT/CTS SA
CTS & VAC SA
Choke SA
Launch Mode SA
Highway SA

Then subtract off:

IAT/CTS Bias SA
CTS & VAC Bias SA
N2O Retard SA
Boost Retard SA
TCC Locked SA
Knock Retard SA

Then if in idle add or subtract the idle compensation SA

Note that the initial SA is also subtracted out. The physical position of the distributor adds it back in. So it makes sense to leave it out of the above.

RBob.

 

You got that right?

Mine match up nicely. Assuming steady throttle, CL, conistent coolant temp, EGR disabled, CC disabled or vented to atmosp, launch disabled, and maybe others above disabled or zeroed I would expect it to match. You need to look at your WU logs(analysis) and see if something stands out.

 

So let me see I understand the intial SA subtraction. Let's say there are no adders or subtracters going on. If my Intial SA is at 10* and my SA Table calls for 18* at a certian point, would I see 8* in the log due to the intial SA being subtracted?

 

No. You should see 18d.

 

Thanks so much for the answers. Now I think finally understand SA enough to go see what is truly happening.

 

Make sure the EST connector was unplugged when you set initial SA at distributor?

And double check timing to see if something slipped at distributor.

 

bizzybone485, I hope I am not hijacking your thread with questions you aren't interested in as well.
So, I made a spreadsheet and entered the parameters for SA in 5 examples to see if the total SA would come out to what the log displayed. The first three did, the second two did not. Note: I was in AE for the second 2 but not PE or Launch. Can anyone see by this capture of my spreadsheet why I have a 4 degree delta in one example and an 8 degree in the other? Did I miss a timing subtractor? What is interesting is if I put the value for SA-Non PE Max Retard (8.09) in the place for Knock retard the total comes out right. I don't see where I am getting retard in the one with a delta of 8 degrees though. My log has a value of 1 in the "rt" column in the one that is 4 degrees off and 0 in the one that is 8 degrees off.

 

Just looking at the first box (upper left), there are some items that I don't believe are correct. Likely the choke SA has already decayed out. This on a warm engine only lasts for 15 - 30 seconds.

At 1600 RPM and 38 KPa MAP I doubt the ECM is in PE mode. So that entry should also be 0.

The coolant comp at 0 is likely not correct. For it to not have an affect on the SA it needs to match the bias value (CTS Coolant Comp Bias).

For the subtracts, the stock bias for the CTS/VAC and CTS/IAT are 9.84*. Although they can be changed, and may have been as you have the CTS/IAT SA adder at the same value (they cancel each other out).

If the CTS/VAC bias (CTS Coolant Comp Bias) was changed to 16.17*, the CTS/VAC table (CTS Coolant Comp) will also need to be changed. This is so that at normal operating temperature the ECM won't be adding or subtracting SA.

RBob.

 

Bingo! There is my issue. I do not know when or how I changed the CTS Coolant Comp Bias to 16.87 but it was surely changed and the table never was. I will change that back. One question on the table. The top row is VAC kPa and has 0 through 40. What happens when your VAC is over 40? I just assumed if your VAC was 58, like in the upper left example, that the value would be zero. Also, thanks on the SA-PE. Definitely not in PE. I only added it because it made the numbers look better so I thought it was always added. Now that I know it isn't, and I should focus on understanding coolant comp. As far as choke, the engine wasn't completely up to temp as it was 30 degree outside and I was running no thermostat that day so I think the choke SA add may be legit.

 

When table look ups are past the ends of a table, the closest row/column is used. With a vacuum of 58 it will use the 40 KPa vacuum column. This is true of all tables, 2D and 3D, dependent of the axis(s) for the table.

Choke is really a misnomer. It is really "after start" SA (and also fuel). I stayed with "choke" as there are so many posts using that term. It does decay out quickly, with the CTS & VAC SA compensation being the real choke SA value.

Same with fueling. There is an after start enrichment, and then the CTS AFR multiplier table for enrichment based on CTS.

Check out the Tuning Guide Book sticky on the DIY_PROM board here on TGO. In Chapter 5, '8746/'7747/'8063 ECM section there is a SA logic and Fueling logic write up. And if using an auto a TCC logic writeup.

They are not exactly the same as the EBL (they are '7747 or '8746 based). But do a decent job of explaining what goes on in the ECM.

RBob.