I am completely lost right now

Hello all,

I've only had my MPVI2 and everything for about a week. I got into this because the "tuner" that did my trans am installed the tune i'm uploading and then seemingly moved on... that was 8 months ago. so here I am. I'm planning on getting the tuning school beginners guide but would really like to get this car straightened out a bit so that it's drivable now, so any help is appreciated. It runs really rich and pops and sputters.

The car is a 2002 Trans Am, its a pretty basic LS1 with the LS6 intake, 80lb injectors and a turbo kit with a 98mm turbo running 13 lbs of boost, it has a 2 bar MAP sensor and the MAF has been completely removed.Attachment 89758Attachment 89759

Get yourself a wideband and set it up to log eq ratio error, there are a lot of write ups on how to hookup your wideband in order to log with it. I would go for a drive while logging the data.

Just be safe, like Doug0 says, log afr error and then multiply by -half%. That way you will "sneak" up on the tune. Be sure to have your commanded afr set correctly :) When going into boost specially, watch your knock and timing very carefully.

It would help if the tune was setup for a 5.7 as well. It currently is making calculations thinking it's a 6.0 engine size. It may not be that much larger but it will still throw things off if the cylinder volume is incorrect.

You say it has 80lb/hr injectors but the flow rate has 73lb/hr. So it's wrong for 43.5psi and it's wrong for 58psi if running the stock fuel pressure rating. That needs to be fixed.

As said, using a wideband is key. Set the tune to run in open loop only with zero fuel trims. Then you can take your created wideband error against the commanded AFR to fix the airflow model (Primary VE table.).


Logs need more data too. Add your injector pulse width avg, knock retard, cylinder airmass, commanded AFR, your wideband. Remove the 1 bar MAP channnel, replace it with the 2 bar MAP channel so you can log boost.

If you have the PRO version, wiring the wideband is easy. The standard MPVI will require you wiring in the wideband through a 5v circuit to make it work.

Attachment 89884Attachment 89885Attachment 89886

these are the two run logs I have and the tune in the car. I corrected the engine size and was able to get my wideband to read on the first drive but since then it hasn't been reading any values and I don't understand why as I haven't changed anything in my channels... hopefully there is some info here that will help with the tune. it still runs rich and stumbles badly unless in boost. once it's in boost it seems to pick up ok but I know there's a lot more power there to be had. thanks for any help.

Have you looked for a vacuum leak? your trims are way out there, reset your trims after every log.

Quote:

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Originally Posted by DougO

reset your trims after every log.

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how?

Quote:

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Originally Posted by bk2life

how?

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http://www.hptuners.com/help/index.h...cmcontrols.htm

Looks more like you are setup for 60# injectors and not 80#......Just my opinion....

You've either got a misfire or an exhaust leak on bank 1.