I need help. I just finished building a 383 sbc with the following specs:

4 bolt main
Eagle stroker crank
Scat Rods 6.0
Wiseco Flat tops 10.7 cr
Comp Cams XE282 HR-10
Edelbrock Hi Flo TPI base
Accel S/R intake
Lucas red stripe 40lb injectors
Adjustable regulator
Walbro 255lph fuel pump

The problem is the vehicle will not idle. I've been messing with this combo for over a month now. I've changed the injector constant in TunerPro to 40 lbs and the only way i can get this thing to start is that I keep my foot on the pedal to prevent from stalling. It is running way too rich. Black smoke coming out of exhaust and popping when I give it a little gas. I've pulled all of the plugs and they are black(rich). I've changed the chip parameters back to a stock 350 to see if it helps but to no avail. I've read up on some of the sticky articles and that just made me more confused. My question is where else in TunerPro can I go to pull out some fuel from these injectors so i can get this engine to idle? Should I set injector constant to 30lbs instead? This thing is starting to make my heart palpitate to the point that I'm about to carb it. Any help is greatly appreciated.

 

Which ECM & code mask are you using?

RBob.

 

7730 ECM $8d. I'm using Super_8dm2.ecu

 

OK, if the fuel pressure is 43.5 psi with the vac line off then set the injector constant to 40 #/hr. If the fuel pressure is different then 43.5 #/hr then calculate the fuel flow at that pressure and use that for the injector flow constant.

You will then need to reduce the values in the VE table at lower engine speeds. With the cam the volumetric efficency will be lower at low RPM. This will clean up the low end enough so that you can run the engine and not foul the plugs. Note that you will need to fully re-work the VE tables.

RBob.

 

Thanks for the input. You don't happen to have the formula handy to calculate fuel flow do you? The psi reading is 47psi. I have the LM1 WB datalogger but I haven't hooked it up yet. I'll use that to rework the VE tables. Thanks

 

*edit* beat me to it..

 

I found an online fuel flow calculator and came up with about 42lbs at 47 psi. I will change the constant once I get home and mess with the lower VE tables and see what happens. Thanks for the help RBob.

 

It shouldnt be to hard to get it to idle with the 40 lbs.

Bump up the idle speed untill you get a nice running engine, then you can try to lower the speed some, starting at a low idle speed can be hard to tune.

You will also need to raise the SA at idle.

At what kPa is it idling?

I think I have a 8D*bin, from my "old" 383 SR engine if you want to compare?

/N.

 

Can you pm that bin to me? You can also email it to rivedenn@yahoo.com I'm not sure what kpa it is. I'm kinda new at this chip burning deal. How do I find out? I feel stupid, is SA spark advance? Thanks!

 

You got mail.

I do not recommend you yo use them, becuarse its not the same setup as you have, but check them out to compare and get some ideas what I did.

/N.

kPa is the MAP reading
SA - spark advance

there is also a good thread about idle tuningwith big cams here
https://www.thirdgen.org/forums/diy-...light=big+idle

 

Thanks for your help and for the bins. Now I have a good starting point. I hope these injectors aren't leaking.

 

Ok, I got the car to idle enough to set base timing at 6 deg. I played with the lower VE tables and lowered the values and adjusted the idle screw. Now I'm ready to start tuning this beast. BLM's are 108 across the board which means running rich. My question is this, my scanner measures MAP in volts not kpa. How do I go about converting that to kpa? Also, I used an infrared gun to measure the primary temps. All are reading around 250F except cyl 4 which is reading 475F and cylinder 5 reading 380F. I suspect those two cylinders are leaning out. Here's a screenshot of the scanner data.

 

Valve adjustment may also be keeping the ex. valve open. Do a compression or leakdown, or just check the adjustment.

 

Glad I could help.

Observe that one of the bins was from my 415cui ( if you used them as starting point?)

What scanner do you use?

/N.

This is from a Delphi MAP

 

I used an Autoxray 6000 scanner. It only reads it in volts. I also "borrowed" your lower VE tables on the 383 bin and it seems to have helped but the engine is not happy yet. Is that Delphi graph universal? Can I assume that at 2.5v on the MAP that there is a 50% load or 50kpa?
----------

That was the first thing I looked at when I first started it. The valves turned out ok.

 

Dont know about the MAP readings, I think there is a MAP vs voltage table here on thirdgen somewhere, try search.

You might want to set the two "Idle Spark vs rpm error" tables to 0 while you are tuning the VE, it usually makes it easier. Then when its time for fine tune the idle you can start with those tables again.

/N.

 

I found this table posted a few years back. Here it is for anyone else needing to convert. Wow this car sounds like a top fuel dragster right now. Thanks for the input guys.

 

spent a lot of time trying to figure it out as I have the same injectors and they are 42 lbs not 40 lbs change your injectors to 42 and will lean it out and should be closer. I got the part number did a search and found it under some stan weise page with injector info. I have a post in power adders under what lucas injectors are these with the part number and the link to the page is on there. Most likey your problem.

 

Sound great..

You could also look how the VE table looks like in the 415cui file, that engine had a bigger cam and lower comp than the 383. Just to get you some ideas...

/N.

 

Thanks for the info.

 

Your TPS volts are high, 1 volt, this needs to be set closer to .54 V

 

It's funny you said that because I just measured it before I read your comment and it read .94v. The TPS is of the non adjustable type so I elongated the mounting holes a little and got it down to .68v. Just as I was about to start the car again my wife summoned me to take her to an outlet mall to go shopping. Since it's Mother's Day I had to oblige. Oh joy...

 

The 86 TPS has slotted holes and will work (electrically the same as) the fixed one 92. With the 383, any change in the minimum air flow stop on the TB, will require a change to the TPS to maintain the .54 v

Some days are better than others, bet you get a "mommy thankyou" later.

 

I'll mess with it tomorrow. As far as "mommy thankyou" I'm not holding my breath

 

Its not really necessary to have it at 0.54v for 8D code. Just make sure it goes over 4v when WOT.

/N.

 

When using an infrared scanner for temp readings, I was taught to put a piece of black tape on the reading spot. Painting a black spot would work too.The more shiny the temp reading spot, the more you read the background temp and not the true temp. Check out a candle in a mirror. Or heat up a shiny piece of metal. Galvanized furnace duct will read way off.

Also watch the fan out of the reading beam, around the red dot could be 2" if you are back a ways.

It would seem to me that those two cylinders would be richer not leaner. What do the plugs say?

 

All the plugs are reading rich. I have SLP headers that are ceramic coated. Will that affect the temp reading? I heard lean will make temps go up as well as rich and too far advanced timing so I kinda don't trust that method of tuning. The plugs told the tale.

 

Ceramic coated pipes will run cooler than not coated. Retard the spark and glow the headers red.

 

Ok guys, here's the latest on this running rich deal. I changed Inj, Constant to 42 lbs and went into the VE lower table and divided the entire table by 1.05 which lowered them all by up 12 points just as a start. Base timing is set at 10 deg. When I started the car yesterday it is still running rich between 11.8 and 12.2 afr at cold start and the engine seems to be hunting for an rpm. When the car goes into closed loop all seems fine. AFR stays in the 14.7-15.6 range at idle. BLM.s are at 108 which tells me it is still running rich. Did I miss something somewhere in Tunerpro? I'm using Super8dm.xdf 7730. I just want this engine to run around 14.7 while in open loop so as not to dilute my oil with gas. Do I need to do lower the mv's in the O2 constants table? I'd really hate to blow up my new motor because I changed something I wasn't supposed to. Thanks guys.

 

anybody?

 

You might need to go down lower on the table. First off a large cammed 383 should have around 20 to 25 degrees of timing. This needs to be done in the correct block for the idle so it affects it. Next what is you kpa at idle. Very important to know this so you can fine tune your idle point. My car with 30 lbs injectors with a big 238 242 @ .050 cam on my 350 in my lt1 car idles with 65 to 70 kpa. Not much vaccuum. I have about 34 in those blocks for the idle and fuel pressure is at 38 on that car. If I had a 42 lbs in that car I would probably need around 24 to 26 in that block to make it right. Here is a formula to get you where you need to be but need to you your kpa and blm to do this.Ok here we go. If you have a blm of 108(this applies to what ever you blm is off from 128) take 108/128=.844. Now take your kpa and say it is now 36 in that block just to use, multiply(your actual number)36by .844 and the number you get will be what you put in that block. SO if yours was 36 in that block at 108 blm rich you would now use 30 in that block which should put you at 128 or close to that. try all that and see what happens. Let me know what your kpa is I am curious to see what you are trying to use.If your scanner cant do it you need to get one that does to get this right. using this formula will get you dead on. takes a while but will get you perfect. I just happen to be selling a snap on mt2500 if you are in need of a new scanner. let me know how it works for you.

 

for what you have a set of 30lbs would be plenty for the car. I ran 30s in both my cars that made 400 and 420 rwhp. Just went to the same injectors for my turbo set up now. SO using 42s for a car expected to make 650rwhp and you run them naturally asperated it a little much. I ran this set of injectors (42 lucas) on my 392 inch lt1 that made 525 rwhp and by my tables could have went with less on it.

 

My AutoXray 6000 reads MAP in volts. At idle it's reading between 3.2 - 3.35 volts. If my calculation is correct then that would translate to around 70kpa at idle or about 9" vac hg. There's an attachment on an earlier post in this thread of what my BLM's were. What would cause the car to "hunt" for an idle?

 

You're hunting idle and high kpa (map reading) could possibly be a vacuum leak as well. It took me a good 2-3 days to get my 383 up and running the first time.

 

too much timing can cause a hunting idle. too little also.say you want 850 but it has a rich problem and is causing it to fall off bad.it has a correction factor in the timing of maybe 5 degrees in the program so trying to hold the 850 it might be thowing timing and then goes too far then has to pull back out. I took that on mine and made it only 2 degrees and it got a lot smoother idle. You need to get it closer to 128 then start wondering why it is hunting. May clean up some with leaning it out some. use the formula I gave you to redo your table.70 kpa is what my lt1 idles at and I have 34 in my idle block and it is at 950 rpm with a 6 speed. with your size injectors would say that you need below 30.

 

Are you running a heated O2?

 

No. I'm using a stock one but I have my LM1 WB plugged in just after the y-pipe to measure both banks.

 

This table that you refer to that corrects the timing is it the Idle Spark Advance VS. RPM Error table shown in the attachment?

 

There are more than one way to be out of control.

First the ECM/bin program can be getting the wrong information, and be reacting the correct way (O2 reads lean when mixture is really rich). ECM and program are okay, but the sensors are giving false informational inputs. This either can be a bad sensor/bad wire or sensor reading out of its designed operating range. Output is incorrect for what is needed.

Second the ECM/bin program is not tuned to the engine/operating conditions. All the sensors are reading correctly, but the ECM/bin program gives a incorrect response to the information (O2 reads lean and ECM fails to add the proper amount of fuel, too much or too little). Output is incorrect for what is needed.

Third the sensors are reading correctly the ECM/bin program is correct but one of the output devices is bad (injector, fan, dash readouts, egr, ccp, or alarms). This may or may not effect the running of the car. (think bad/no egr, car runs okay, check engine lite on, or low ohm/leaking injector, no code alarm).

Or it can be a combination of the all three "out of controls"

Using the ecm tune to correct for a bad sensor is done (think of default value tables) and a different sensor can correct for a bad ECM/bin program (think added a WB with NB output).

The cam change and increased overlap (lopey idle) is what will require you to install a heated NB O2.

Check your O2 volts and cross counts. If the NB O2 is reading rich mixtures, it can soot up and give false readings at low speeds. Fuel fowled plugs missing and sending raw fuel and extra oxygen to exhaust. After a hotter, higher rpm run, it will clean out, and read different, for a short time.

If the NB is close to the head (stock location) and the WB is farther down the exhaust pipe, you can get different readings due to combustion (oxygen lowering) taking place between the sensors. The first will read lean (more oxygen) and the second will read rich (less oxygen).

If your 42# injectors, at min pulse width, spray more fuel than is needed for idle, then the ECM has lost control of the mixture (blm at 108, integrator at 100 ?).

There are many "fudge factor" tables in the bin programs to compensate for the short comings of the injectors (I know they are there, but not what/how much to change).

I am still learning the Maf system going on 9 months now. This is a mild DD, it hell to be dumb at this stuff.

On my car, it is the exact opposite, idle is reading lean (blm at 160 integrator at 180) car chugs, smells rich, and stalls. I changed the blm high limit to 140 and it runs. Injector pulses should be (on my car) 2.0 ms at idle (from earlier data logs). At the blm 160, injector pulses are at 3 ms, way too rich. At 140 blm, injector pulses are at 2.2 ms (rich but more runnable).

This is caused by my O2 going cold at idle and PT (55 mph), low O2 volts and cross counts causes the ECM/bin program, to add fuel (false information from O2).

This happened when I added a new 2.25" dual exhaust, because the stock exhaust rusted out and broke in two, under the rear end (kept the stock intake and stock exhaust manifolds, for now, 1 3/4" shorty headers ready for later).

I will be adding a heated NB and a WB to the exhaust, when all the parts arrive.

 

I'm running 42# lucas injectors at 46 psi on 350 cubic inches with no issues. They did require some tuning however.

To make them work well, I had to get into the low pulse width offset and battery voltage compensation and I also set the min pulse to zero. This was done with a 165 ecm and 32B masked bin other ecm/masks should have similar options if you get deep enough into the hac.

My injector pw at idle is down around 0.75 ms depending upon the airflow. I have no idle issues with the low pulse widths. Up top, I see about 90% duty cycle. These are the right injectors for my set-up.

I don't see any reason why they won't work for you if properly tuned.

 

I am curious what/much is "up top" @ 90% dc?

Pics is too small for me to see, what (if any), HP adders.

And why the 32B not the 6E? Tables vs Calculated?

 

"up top" for me is about 5800 rpm and 7-8 lbs of boost.

For a power adder, I'm using a Powerdyne BD-11A with upgraded impeller spinning around 42,000 rpm. It is blowing through a range extended (voltage divided) Ford 05+ slot style maf in a 3" tube to measure the airflow as well as the blower discharge air temperature.

Above 5300 rpm, I'm now pegging the Ford maf with 6 volts at the sensor or 5 volts at the ecm after attenuation. With my current extended range calibration, this represents 450 gm/sec. With 90% duty on the 42s, I'm seeing about 900-920 mv on the O2 so its not too far off.

My car is an 88 4+3, so I need to run a $32B mask for the 4+3. Its not worth the trouble to me to hack in the 4+3 stuff into $6e. I can live without Highway mode fueling and the other small differences between the two masks.

For fueling, I'm still using the calculated values instead of the LV8/rpm table. I don't see any need to use the table. The calculated values work fine.

I've modified and tuned my 165 ecm and bin to handle the Ford maf signal and support extended airflow up to 510 gm/sec by basically cutting the MAF resolution in half and correcting everything that is affected by airflow for the new resolution, like the load calculation and O2 tables etc.

The current sensor only seems to handle about 450 gm/sec when extended, but this is sufficient for my needs. Extended range sensors like the HPX would work for even higher power levels, but they're more than I need at the moment.

Power should be somewhere north of 400 RWHP.

In any event, my point is that 42s can be made to work at idle with even small cubes and also can provide sufficient capacity for impressive power if required. I don't see any real downside to being "over-injected" if you can deal with the tuning requirements.

Hopefully the OP can get his injectors to work for him.

 

yes that was the table I was refering too. Shorten it to 2 degrees. Also my car ran like crap with a stock o2. I now use a 94 chevy pickup 3 wire heated and it was night and day for cold start up. Also shortened the time to go into closed loop up to help with it. Being that the other guy has a blower and I run a turbo is enough reason to go with the large injector but for n/a 400 rwhp 30lbs would be plenty and make all this go away. Plus you can score a set cheap and sell off the lucas for decent money. They are very expensive new and quality injectors not like a fms green 42.Nothing wrong with them just not a 800 dollar injector. (what mine cost 8 or 9 years ago). If that stock single wire is old it may be toast and be causing all kinds of havoc. check out code $59.org. Lots of n/a guys are going this route to be able to have a wide band o2 in the loop for closed loop operations. How cool is that. Have seen guys say there car never ran so good or as close to stock with that set up in the 730 ecm. WHat I am doing for my turbo set up so I can tune up to 30 lbs of boost in the tables. uses a 3 bar map for boost side. No fmu to screw up things with this.

 

Just to add some info, the Calloway vette 1987 twin turbo, used a ABTB (7741) chip (4+3), then had a MAP (KPA) sensor to run a FMU. The fuel was added through two additional injectors mounted between the turbo coolers and the TB spraying directly straight into and at the TB blades (looks like a sideways TBI). Back then the larger 42# injectors where not a reliable option. It also ran with a stock MAF unit (screens and all).

 

Ok, I believe the rich idle condition is under control. Now I have an issue with the surging/hunting idle deal. My idle is set at 850rpms and base timing at 10deg(est disconnected). It does this during open and closed loop operation. Could it be a vacuum leak causing this idle problem or something in the eeprom?
I've read over the thread about tuning a big cam and surging idle but some of those tables in there are not even in Tunerpro. Does O2 constants have soemthing to do with the this idle issue I'm having? Can I change soemthing in the IAC tables to help things?

 

ttt

 

You should check for vacuum leaks and be 100% sure before try to tune it, otherwise you be chasing youre own tail.......

* Some cams/engines like to idle at diffrent AFR's what does your WB show at idle? changing the O2 constants will get you a diffrent AFR at idle and maybe that will help you.

* Timing- whats your timing at idle? Timing vs rpm Error? have you tried to play with it?

* What does your IAC do at idle? If its hunting you could try to "slow" it down, cant remember the constants name right now.....Try open the blades to you have 0 IAC steps at idle.

 

If the mixture is too rich at idle then it will surge/stumble, even if the O2 says it is lean, it can be rich (cold O2 or exhaust leak). A good idea is to get to know what injector ms = "a good idle", this should not change much later on when tuning.

When the engine gets down to the stall thresholds, the ECM action is, richen the mixture, then the IAC adds more air to this rich mixture and hopefully the engine recovers.

If you are already too rich at idle, then when the extra fuel is added, the engine drowns, which has two out comes.

If the IAC can add enough air, the engine will rev high, and bounce between high rev and low rev rich stumble (classic vacuum leak symptom).

If not enough air added, then the engine just stalls, This can be after a few roller coaster rides of high rev low rev stumble.

When 42# injectors are used, it increases the "gain/ramp" in the rich/lean feedback loop. Even though the injector constant is changed, the fuel comes on faster then the ECM expects it. This causes an overshoot condition which sends the ECM into this "dog chasing it's tail" surging.

This is worst at idle because, "a little pulse width" is "a lot of fuel". The cause is likely, the lag of opening and closing the injector. Think of that 58 mm TB, "a little change" is "a lot of air".

 

Base timing at idle is set at 10deg but I'm getting some knock when I blip the throttle so I had to back it down some. I wonder if the gear drive is causing the knock counts? Timing vs. RPM is set at 2 deg. I will try the IAC thing after I check vacuum leaks. I wish all of the tables in Super Aujp had comments that explains what they do which will definitely make things alot easier for tuning amateurs like myself Thanks for the input guys. I will report back later with results.

 

While the engine is idling/surging, data log and note everything that is "roller coasting". There will be a set of values that are "in the middle" of the up and down. These values, inj ms, spk adv, IAC counts, map/maf, rpm, and O2 mv, all will have a mid point, this is where the engine is trying to set but something is upsetting the normal steady state.

If these values have different mid points then there will be no steady state.

There are also programmed delay/gain tables associated with some of these values. Low gain/long delay makes for a long "motor boat" type of roller coaster, and high gain/short delay makes for a "quick hyper" type of reaction.

An example (of too quick) would be if the engine response was slow, add fuel (or what ever is being controlled) get no response, add more fuel still no response, add more fuel, get all the fuel at once, now too much fuel remove no response, remove more fuel ect.... this makes for a very uncontrollable system.

The gain/delay can be in the system (engine) or the program.The gains and delays in the program have to match the natural system (engine) response time.

So when anything is changed on your engine setup, all the natural system responses change, you have to find the new "magic numbers" to load into your tuning program.

This is one of the reasons why, if more doesn't work try less.