This is probably way over your head, unless you are in the top 5% ;)

The car is a Trans Am with Vortech s/c kit. Stock cam and everything. Just headers and the kit with some FIC 80# injectors. The car was brought to me originally with Deka 60's that I blamed at the time for the strange problem. I sent the injectors to John at FIC at he said they were rusty and basically a huge mess. So I threw on some fresh 80's with FIC's data, and still... same problem.

The Problem: Idle is rich rich rich.

I have 2 widebands on the car and both show in the neighborhood of 10.5-11:1 a/f at idle till the fuel trims kick in and remove 35-40% of the fuel. As soon as I get out of trim cells 20 and 22 everything goes back to hunky dorey. I have tried everything in my mental capacity to fix this problem, to no avail. Last time was when it had the Deka 60's, now this time with the FIC 80's. 2 sets of injectors, same set of problems. I don't think it's injector data related because both times I have used what has been presented to me by John at FIC, as correct data. And I use FIC injectors/data all the time and have never had this problem.

I have leaned out all the start up enrichment to no avail. Nothing I do fixes the problem, that's why you will even see the VE multiplier table all wacked out because I literally have tried everything to fix this issue. I even put a value of 1 in the VE between 0-1200 rpm and 0-40 kpa. Only thing that did was made the car sound like it had a cam as the computer went from rich to lean rich to lean.

I've put solid values in the MAF, set it to 1, with the VE at 1, it was the best in regards to fuel trims when I did that, but I can't leave a stock cam car sounding like a dragster ;)

Soooooo, I really have no idea and have never had a car do this before. This is very weird and it's going to take some real digging to figure out. I've done write entires with completely new files to see if that would fix it, but no matter what I do, still same problem.

Here's a short log as well as the current clusterfuck tune. Compare it to a stock 02 A4 to see what i've attempted to do that hasn't worked.

Attachment 39705Attachment 39706

btw disregard wideband on data log, that circuit is open.

Ive heard (havent tried) that you need to drop the min pw on some injectors to have them be acceptable at idle. Might be worth a shot, Im against fudging injector data but from what Ive seen the data for those injectors isnt completely accurate.

FIC is still giving out barely modified Injector Dynamics data I see.



What's the prize for having the answer?

What vehicles have you used these in before? Other F-bodies, or a C5? Because you'd have the same problem in those too.

you are aware that those 80s are rated at 43.5 psi correct? at 58 psi you'd have to set them to 96 lb/hr injectors

I ALWAYS set the minimum pw to 0 in all my tunes, typically idle pw at around 800 rpm with those 96s should be around .9 ms, it will vary depending on your cam and what not but that should be close

if you need any of the injector offset info shoot me a PM

your default injector pulse width is set to 1.277 and your transient may need to be lowered to if that doesn't work

Quote:

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Originally Posted by flame

your default injector pulse width is set to 1.277 and your transient may need to be lowered to if that doesn't work

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Yep. Transient fuel and min inj. pulse width/default pulse width.

You'll need to redo the MAF and VE now.

Attachment 39778