VE tuning fails

[Schmieder]

1996 Grand Prix SE (1997 Lumina PCM)

I had set the MAF to fail at 0Hz. I have 36 lb/hr injectors and they are set at 32.44 lb/hr in the PCM.

Before I disabled the MAF, the car runs fine idling and easy driving (no PE), and the AFR is 15.7 at idle and 14.7 in drive.

When the MAF is set to fail, the car idles at 16 AFR and after a few seconds it dives into an extreme lean condition and stalls out. My VE tables are present and the VE for the idle and map when started is around 45

It should run richer due to the injectors being set at 32.44 instead of 36. I am confused and need help, please.

btw, I had installed a new custom turbo. I have no error codes when idling and there is proper fuel pressure. The stock O2 sensor is new and I have a WBO2 (obviously, lol)

I am stumped, please help.

Thanks

[LETZRIDE]

when i started my ve tuning I selected my VE table and multiplied the entire thing by 25% just to richen up the whole table...you would rather run rich and pull fuel then be lean...so I would richen your entire table up by atleast 25% then rescan and see what happens...then start collecting you % error afr and putting that into the ve table...

[Schmieder]

when i started my ve tuning I selected my VE table and multiplied the entire thing by 25% just to richen up the whole table...you would rather run rich and pull fuel then be lean...so I would richen your entire table up by atleast 25% then rescan and see what happens...then start collecting you % error afr and putting that into the ve table...

That I will do. Though, the injectors are set at 32.44 where they are actually 36. But setting the VE rich and setting the inj as they are seems a better idea.

I forgot to disable DTC p0103. Once I disabled the DTC it ran ok. I have to be more careful. Though I can't see how the DTC p0103 would cause a lean stall. But it hasn't happened since I corrected it.

Thanks!

[LETZRIDE]

what is DTC PO103? if that is the code for the Maf failure, the reason why it would run ok after that is because by disabling that you are telling the pcm to ignore that code, and not check for failure...therefore you are running off the MAF tables again...

[bilemke]

Yes. P0101, P0102 and P0103 are MAF codes.. if one doesnt get triggered, it will try to use the MAF again.

[SweetS10V8]

Why dont you have the injectors set to the correct value??

[TeacherCreature]

Yea put your injectors right and dont play with the code - Part of hte VE tuning your not gonna expect the car to run "right" in speed density

[LETZRIDE]

it runs fine in SD mode...you just have to cheat a little...

[darkhorizon]

1996 Grand Prix SE (1997 Lumina PCM)

I had set the MAF to fail at 0Hz. I have 36 lb/hr injectors and they are set at 32.44 lb/hr in the PCM.

Before I disabled the MAF, the car runs fine idling and easy driving (no PE), and the AFR is 15.7 at idle and 14.7 in drive.

When the MAF is set to fail, the car idles at 16 AFR and after a few seconds it dives into an extreme lean condition and stalls out. My VE tables are present and the VE for the idle and map when started is around 45

It should run richer due to the injectors being set at 32.44 instead of 36. I am confused and need help, please.

btw, I had installed a new custom turbo. I have no error codes when idling and there is proper fuel pressure. The stock O2 sensor is new and I have a WBO2 (obviously, lol)

I am stumped, please help.

Thanks

If you have a turbo, you have to run a maf, which means you will never use VE tune stuff anyway.

[Schmieder]

Thought I'de update the situation.

The problem was the fuel pump. It was burnt and wasn't delivering the proper fuel flow. I put in a walbro 255 high flow and it was a difference like night and day.

My VE tables are tuned. I did that by reducing the WG to near zero boost. This means the ve tables are tuned right since the turbo will help air flow even when not in a boost situation. I will be getting a 2-Bar MAP soon to protect my engine if a MAF failure were to ever happen while into boost.

After which I tuned the MAF while set to 7psi boost. My fuel trims are in the +/- 0-1 range.

WOT was tuned to 11.5-11.3 AFR w/ wideband.

I have a good spark advance so far with zero KR. Running 93 pump gas.

I have torque management set to 320 lbs/ft as a safe guard for my 4T60-e auto-trans. I will be trying for a manual swap later next year.

At 7psi my 3100v6 is pushing 350 lbs/ft according to log files. Someday soon I'de like a dyno tune to fine tune my work.

She is fast, Fast, FAST!!!

I have to learn how to work the throttle now as anything over 80% at speeds lower then 40mph will induce spinout right then and there. It seems there is very little turbo lag.

I do need to investigate more technical approached for spark timing. As far as I have been told, reducing spark at a power idle just before launch can help spool up the turbo faster (1/4 mile drag).

EDIT: Fuel pressure was fine at idle but dropped under load. I didn't monitor the pressures under load, hence my belief pressure was fine. But after some more thinking and logging it became obvious it was a fuel delivery issue.

[Khipset]

What other mods are you running other than Turbo, injectors, and fuel pump?

[Schmieder]

What other mods are you running other than Turbo, injectors, and fuel pump?

Smoothed the short side radius in the intake and exhaust ports, removed casting defects through intake, gasket matched, TB opened up (threads cut down, one bar removed, screws sunk in plate, ect), 2.5" mandrel exhaust, 4* cam advance (custom ground key), a-a intercooler, trans cooler at 9.4k btu, EGR disabled, cat delete, all exhaust 2x's heat wrapped from heads>turbo>test cat, spark plugs 2* colder and 0.045" gap.

Tuned spark for 91-93 octane only

shift points adjusted to match greatest power in rpm range (butt dyno and dyno sim for PC)

New NB02 upstream, new cam/crank sensors, new TPS, new ECT, Cleaned MAF, new plug cables, new radiator, new water pump, new coil packs, new fuel filter, high flow air filter.

I think that is it, I may have forgot somethings.

EDIT: I tuned the AFR like this.

Idle and light cruise - 14.4 AFR (estimated 5% ethanol 93 octane)
PE under 3200 rpm - 13 to 12.5 AFR (n/a power)
PE over 3200 rpm - 11.5 to 11 AFR (FI power)
0 to 2sec -0.0AFR
2-6sec 0.0>-0.5 AFR
6sec+ -0.5AFR

It really seems to help power through out the rpm band and reduces knock even further.

[Beau]

Reduces knock? You should probably be tuning on the side of zero knock no?

[darkhorizon]

This means the ve tables are tuned right since the turbo will help air flow even when not in a boost situation. I will be getting a 2-Bar MAP soon to protect my engine if a MAF failure were to ever happen while into boost.

The VE table does NOTHING with the maf plugged in and functioning. You could zero out the VE table and have no change in fuel trims.

It is impossible to put a 2bar map on without custom OS changes, you can not just change a few tables around.

[MMGT1]

I hate to do this to you, but, if those are the 36lb GTP injectors you are using, set them to 34.10 across the table. Re-map your Maf for the changes that will occur. Then, new plugs, drive it for a week, get your fuel and spark in line the way you want. Pull plugs and look for a rich or lean condition in any of your cylinders. If you find anything, adjust in "skew" table and then check again ofter a good drive. "Some 3.8's, .4s and .1s will have a little lean spot in the #1 or #6 cylinder." You may have already fixed this issue with the walbro you installed, but still worth the check to make sure. My engine builder has dedicated almost ten years into the functionality of those injectors in a 31/3400 and this is what we have used for almost 5 years now. It is the value that he is using in any and all 36lb injectors in these v6's.(yes, he also adds the walbro to the system so the value should be right for you as well)

Just food for though

[TGP-37]

Been a while since I posted.

Thought I'de say the tuning phase is done and she is running great.

Tuning is one of those things you THINK you know what you are doing at first. That is the danger of being a noob to tune. Now I enjoy a turbo with the Fuel Trims locked in tight and the Accel Enrich/Decel Enlean just right (took a while).

I'm still MAF but I have a 2-bar MAP installed and adjusted the tables. In VE, the 100kPa settings are copied to the 50kPa. 40kPa copied to 20kPa, 60kPa copied to 30kPa, ect.

So my VE is actually 20, 40, 60, 80, 100, 120, 140, 160, 180, 200. It is tuned up but not used yet, hence MAF. This allows me to measure boost pressures in an OS that can not utilize a custom SD OS. Fudging the tables, I lose a little resolution but the PCM still measures finer points of data between input variable points.

I need to build a good SD Tune for future turbo builds that will surpass any MAP I can toss at it. I have considered OL, but not sure yet.

Anyways, all worked out well. HP Tuners are GREAT!!! Well worth the $$$

[bilemke]

Been a while since your last post?

That was your first post.

Just a heads up, there are more tables that reference MAP in use in your car then what you see now in HPT. Running a 2bar map without changing all of them is not a good idea if you didnt change the main MAP sensor config settings

Been a while since I posted.

Thought I'de say the tuning phase is done and she is running great.

Tuning is one of those things you THINK you know what you are doing at first. That is the danger of being a noob to tune. Now I enjoy a turbo with the Fuel Trims locked in tight and the Accel Enrich/Decel Enlean just right (took a while).

I'm still MAF but I have a 2-bar MAP installed and adjusted the tables. In VE, the 100kPa settings are copied to the 50kPa. 40kPa copied to 20kPa, 60kPa copied to 30kPa, ect.

So my VE is actually 20, 40, 60, 80, 100, 120, 140, 160, 180, 200. It is tuned up but not used yet, hence MAF. This allows me to measure boost pressures in an OS that can not utilize a custom SD OS. Fudging the tables, I lose a little resolution but the PCM still measures finer points of data between input variable points.

I need to build a good SD Tune for future turbo builds that will surpass any MAP I can toss at it. I have considered OL, but not sure yet.

Anyways, all worked out well. HP Tuners are GREAT!!! Well worth the $$$

[TGP-37]

Been a while since your last post?

That was your first post.

Just a heads up, there are more tables that reference MAP in use in your car then what you see now in HPT. Running a 2bar map without changing all of them is not a good idea if you didnt change the main MAP sensor config settings

Hmm, This thread is my thread. So I must have posted at least one other time, lol. Oh well, must be another account or some funny mix up.

Interesting what you say about the map settings. I have found a few tables else where that referrence the MAP and I had adjusted accordingly. But I just realized there are tables HPT can't adjust or even show?

Well, it runs good so far. Any tips how I may be able to access the other tables? I am familiar with linux and have moderate PC-Hacking skills. I have altered firmware in phones and digital cameras, shouldn't be that much different.

Off hand, would you know any important tables that referrence the MAP that aren't displayed in HPT? SUppose I may be able to alter other ways to accomodate the 2-bar map.


As far as AIR/FUEL/SPARK is concerned......the 2-Bar is measuring vacuum and boost accurately so far, the AFR are spot on and the spark is where it should be as well. Oh well, if my 2-bar trick is going to fail.....I'll be going megasquirt or wiring in a later model pcm somehow.

Thanks

[Phantom]

This was Schmieder's post but if you are him I will start with you should not gasket match the intake runners it should be ~0.1 smaller or matched to the heads otherwise it hits that smaller lip and adds turbulence, the solution to that is to not match the heads to the gasket and blend it.

For the issue of accessing the other tables not currently available you should search for the program "Tiny Tuner" the down side to that is you will need to find a .bin version of your OSID. Other wise find an os for a compatible supercharges VCM and use that to run the 2bar MAP.

[ssms5411]

I know when I ran 36LB GTP injetors in my car they were scaled from 32-33 across the table then fine tuned them with PE, worked great. I run 65lB Motron injectors now since the turbo will be going on a GT35R water cooled .6/3 A/R and just for N/A they are dialed in at 57-58 across the board and fine tuned with PE , to set your LT LIFts you need to dcale the injectors just right, mine ended up wih a -4 to +4 sometimes 0 , I have never tried VE tuningand bever will dince the way I have been doing it for 9 years works perect. Will see when the turbo goes on and I run 10 -15 lBS of boost which should be about 400-450 WRHP out of my 3.8 not to shabby, mods are in my cardomain site too many yo list, decided on not installing the newer heads with the bigger manley vals and all th eextra stuff, just going to tun it as it sits, then if something blows I will have the motor redone with some J.E 9:9.1 forgered pistons with some low 12 lBS of boost. Hop to hit low 12's high 11's, anything more will be a plus. Once I get another DD GMC 1500 5.3 seirra, its going to be all out with it to see if I can max my .6/3 A/R to 18 LBS of boost with a AEM boost controller it should make it easier and AZ's weather Its the perfect time to try it. Esp. in a 2800LB car. Only thing keeping is the A/C compressor. Still have about 100 lbs to yake off for the track so it might br around 2700lbs in track condition with no pass. seat But i refused to gut the car since it can be a DD and not a complete track car.