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.