C5 M6 new engine mods, idle tuning issue

[HT99]

Hi, I added the following to my engine, need help with tuning idle settings.
Engine starts and idles rough for a few mins then stalls. (1st hpt and log files)
DTC error: P103 MAF

Would appreciate any help, thanks.

I updated the idle settings for Base Setup.
Runs much smoother for longer then stalls (2nd hpt and log files)
No DTC errors

Fuel pressure is 50 lbs at start up and increase during idle to 60-65.
3/8 tank of fresh 93 octane gas
Clears all DTC?s and also cleared error history in dash.

MODS
1999 LS1 engine, stock bottom end, stock pistons
A&A V3si blower, 3.6 pulley, innovators west 10% overdrive damper

BTR stage 1 Blower Cam (Dur @ .050 217 23x, Lift .619 .607)
799 ported heads stock size valves, stock deck size, not milled.
BTR double springs, stock rocker arms, LS7 lifters, 7.4? pushrods

FAST 92 intake, 3 bar MAP sensor (AC Delco 125 92525)
LS2 90mm throttle body
Racetronix fuel pump FOA-005A, rest is stock
Deka 80# injectors

Elite engineering catch can, 1 exit port to engine intake, 1 exit port to blower intake (when in boost)
1 3/4 stainless steel headers with high flow cats and Corsa Indy exhaust

[weinerschizel]

Maybe this is what you mean by idle base setup? If not. maybe...

You need to calibrate your IAC. I'm not exactly sure how to do that on the electronic throttle which you have. It's a bit different than cable setup I have.

Once you have it idling you have to adjust your idle airflow... I believe that's this table:

Engine->Idle->airflow->Base Running Airflow->idle Airflow

Log corresponding PIDs to recreate that table in VCM scanner.

You will start your vehicle logging data... while idling (DO not step on gas). Do this from cold start to operating temperature both for P/N and in gear with Brake on.

It's pretty crude explanation but maybe that's your trouble. You're not getting correct idle airflow for given temperature and it's stalling out the engine.

I did this around a year ago on my build but I have a cable driven throttle body and IAC... It's a bit different on an electronic throttle.

[HT99]

Maybe this is what you mean by idle base setup? If not. maybe...

You need to calibrate your IAC. I'm not exactly sure how to do that on the electronic throttle which you have. It's a bit different than cable setup I have.

Once you have it idling you have to adjust your idle airflow... I believe that's this table:

Engine->Idle->airflow->Base Running Airflow->idle Airflow

Log corresponding PIDs to recreate that table in VCM scanner.

You will start your vehicle logging data... while idling (DO not step on gas). Do this from cold start to operating temperature both for P/N and in gear with Brake on.

It's pretty crude explanation but maybe that's your trouble. You're not getting correct idle airflow for given temperature and it's stalling out the engine.

I did this around a year ago on my build but I have a cable driven throttle body and IAC... It's a bit different on an electronic throttle.

Thanks. I?m away this week but will look at it next week.

[edcmat-l1]

Injector data isn't right. What's happening is when it goes into closed loop the trims pull the fueling down and it actually runs itself out of fuel because you don't have proper control of the injectors at idle. So before it can get to stoich and get into a nice oscillation it kills the motor.

PS has nothing to do with your idle control (airflow) settings.

[SiriusC1024]

It's not right for a boost referenced reg that's for sure. Where'd you get the data? That Offset shape looks familiar, and it also looks like you input the 3 bar data.

[HT99]

Weinerschizel, Tried it but no change

[HT99]

Injector data isn't right. What's happening is when it goes into closed loop the trims pull the fueling down and it actually runs itself out of fuel because you don't have proper control of the injectors at idle. So before it can get to stoich and get into a nice oscillation it kills the motor.

PS has nothing to do with your idle control (airflow) settings.

Any suggestions on how to resolve it?

[HT99]

It's not right for a boost referenced reg that's for sure. Where'd you get the data? That Offset shape looks familiar, and it also looks like you input the 3 bar data.

A friend with a boosted c5 gave me the file, however his injectors are not 80#. I think he entered 3 bar data.

[SiriusC1024]

Want help with setting up the data?

[Alvin]

Hi, I added the following to my engine, need help with tuning idle settings.
Engine starts and idles rough for a few mins then stalls. (1st hpt and log files)
DTC error: P103 MAF

Would appreciate any help, thanks.

I updated the idle settings for Base Setup.
Runs much smoother for longer then stalls (2nd hpt and log files)
No DTC errors

Fuel pressure is 50 lbs at start up and increase during idle to 60-65.
3/8 tank of fresh 93 octane gas
Clears all DTC?s and also cleared error history in dash.

MODS
1999 LS1 engine, stock bottom end, stock pistons
A&A V3si blower, 3.6 pulley, innovators west 10% overdrive damper

BTR stage 1 Blower Cam (Dur @ .050 217 23x, Lift .619 .607)
799 ported heads stock size valves, stock deck size, not milled.
BTR double springs, stock rocker arms, LS7 lifters, 7.4? pushrods

FAST 92 intake, 3 bar MAP sensor (AC Delco 125 92525)
LS2 90mm throttle body
Racetronix fuel pump FOA-005A, rest is stock
Deka 80# injectors

Elite engineering catch can, 1 exit port to engine intake, 1 exit port to blower intake (when in boost)
1 3/4 stainless steel headers with high flow cats and Corsa Indy exhaust

IAC isn't a thing to worry about with FBW.

Proper injector data is key to getting this to run correctly .

I'd encourage you to do a 2 bar OS unless for sure you plan on running more than 15 pounds. You will have better resolution that way. It's ok to use a 2 bar OS with a 3 bar sensor.

[HT99]

Want help with setting up the data?

Thanks for the offer, I will need help.

Since I will start from scratch, do you recommend starting with a MAF tune to work out issues, then switch to SD tune?

Unfortunately, family issues will prevent me from working on this until January.
I?ll reach out then, thanks

[HT99]

IAC isn't a thing to worry about with FBW.

Proper injector data is key to getting this to run correctly .

I'd encourage you to do a 2 bar OS unless for sure you plan on running more than 15 pounds. You will have better resolution that way. It's ok to use a 2 bar OS with a 3 bar sensor.

I originally started with a 2 bar sensor and the scanner logs showed the sensor was pegged at 45 or so even when I accelerated.
Test the harness and it had 5v to sensor. Didn’t know how to test sensor itself so I switched to a 3 bar I had on hand.

2 bar will be good as I don’t anticipate to exceed 15lbs, maybe 12 tops.
Good to know I can use a 3 bar with a 2 bar OS.

Since I will start from scratch, do you recommend starting with a MAF tune to work out issues, then switch to SD tune?

Family issues will prevent me from working on this until January.
I’ll reach out then, thanks

[Alvin]

I would do that setup in strictly SD/VE if it was me.