Commanded Rich AFR

[pdyoung]

Hello, i was wondering if anyone can tell me what is controlling the computer to start commanding a rich AFR, 7.9-8.5 7 to 10 seconds after my truck starts on the first cold start of the day. Sometimes the motor will stall. I don't have a wideband to see how actual rich it's getting but the injector pulse width is going up at the same time the computer is commanding the rich AFR, I can also feel the truck starting to idle real rough while this is happening. It only last for 10-20 seconds before the commanded bounces back up into the 12's. I've just about given up trying to figure this out. I'm currently logging and tuning with HP Tuners, i'm going to try my EFI Live to see if there any other tables that HP does use that i can fool with. Any ideas would be greatly appreciated

[joecar]

Post your tune file and a log file.

What year/model/vehicle...?

[pdyoung]

Thanks i will post the tune and a log as soon as i figure out how to use EFI Live, been using HP Tuner and i get no help over on their forum,

I have a 2011 GMC Sierra 6.2 E38, E-Force Supercharged,custom cam, headers, 90mm Throttle body, The truck runs beautiful,other than the cold start issues,i know this can't be good for my spark plugs

Tune and a log coming soon, please bare with me

Thanks

[pdyoung]

OK,

I managed to figure out how to make a log and attach it a along with the tune that is in my truck now.

My truck runs real well, there is more power and better WOT tuning to be had, but i need a wide band installed, which is coming up in April.

This log was made with a 64 degree start up temp, this was not the first start of the day, which is always the worse start up of the day.

You can see in the log that, at intial engine fire the commanded AFR is in the 12's, that's good, then 20 or 30 seconds running , the Commanded goes into the 8's and the engine starts loading up, then a few seconds later it goes backup into the 12's,on it's way up too 14.68 and all is well the rest of the day. You can also see the injector pulse width increases also.

I have only used HP Tuners and the tables they provide to find out why this is happening, but i give up, can't figure it out and no one on the HP Tuners forum knows how to fix it either.

I hope some very experienced, smart tuner can help me out on this forum.

Thank in advance,

Paul

[joecar]

Can you also post the stock tune file for your truck.

What mods do you have...?

[pdyoung]

I don't have a stock tune file in EFI format, i have one in HP Tuners format that i got off of their tune repository.

I listed my mods back two posts,but here they are again,, E-force Supercharger, custom ground cam retaining VVT, ID 850 Injectors, 90mm Throttle Body, pre blower Meth


Can you also post the stock tune file for your truck.

What mods do you have...?

[pdyoung]

What happened to my help ?

[joecar]

Sorry, I'm a little backlogged, I'll get to it on Saturday.

[joecar]

What does the pid SAE.LAMBDA show...?

[joecar]

Hmmm, LTFT's are different across banks... we have to find out why.

[pdyoung]

I don't know about logging any lamda pid. Could config me a PID list to log, i'm not to familiar with the workings of EFI Live? As far as the LTFT being different from bank to bank,are the fuel trims even active in start up open loop? That is the only area i have concern with at this time. All other engine run time is ok with me at the moment, it's just the start up commanding a super rich conditions shortly into the start up while still in open loop.
Hmmm, LTFT's are different across banks... we have to find out why.

[joecar]

I'm still looking at your files, trying to see what is causing the commanded rich startup...

[pdyoung]

I think i figured it out with HP Tuners under Engine>fuel>open/closed loop>Misc>Hi Di Enrich>Disable, i don't know what it controls but but it stopped commanding the rich AFR at cold start. To be honest between this forum and HP Tuners, i didn't get a whole lot of help on this, took a lot of trail and error to figure it out and that is somewhat more gratifying.

[joecar]

I think i figured it out with HP Tuners under Engine>fuel>open/closed loop>Misc>Hi Di Enrich>Disable, i don't know what it controls but but it stopped commanding the rich AFR at cold start. To be honest between this forum and HP Tuners, i didn't get a whole lot of help on this, took a lot of trail and error to figure it out and that is somewhat more gratifying.Can you post your HPT file and a screenshot... can you also post a stock HPT file of your vehicle.

Sorry, I'm pretty much swamped looking at/correcting people's tunes, mostly for free (I get a moderator's fee, but looking at and correcting people's tunes is my own doing)... and E38 has a lot of stuff that I usually don't get to play with (unlike the LS1B tunes on a Roadrunner)... and when other stuff is going on, I get a bit behind... I agree when you do trial/error you tend to learn something.