imagen2k

Hey guys,

I have a 00' Z28 with a mystery cam thats run horribly after being tuned. Was street tuned a tad to fix old parameters from a previous owner that supposedly were awful, and im pretty sure we tuned it on a melted 02 Plug. After replacing that plug, all of my running issues that were intermittent became constant.

First, I had the car switching back and forth from open loop and closed loop, and fuel trims were extreme. I'm talking upwards of 30-40% in opposite directions on each bank. Car feels like its misfiring like a **** with any throttle. Smoking out the exhaust pretty bad. Smells like fuel not oil. Now stuck completely in open loop and doesnt provide fuel trims whatsoever.

I don't know what needs to be fixed as far as parameters go and I was hoping for some advice. Tuner buddy is out of town and i'm a broke college kid, so a proper dyno tune is out of the question. However, I would like to have a someone take a look and see if maybe something isn't quite right.

Files are attached. Any tips or pointers are appreciated.

"original" is my tune before any issues started.

gametech

iTrader: (1)

I did not bother to look at your logs, because your description of the problem simply screams "mechanical issue". You cannot tune out mechanical issues. Go back to basics, and fix your parts. While you are at it, try to find out what parts you actually have. Once that is done to the best of your ability, post relevant questions.

imagen2k

When the problems started, I ended up pulling the throttle body and maf and cleaned them.

I Swapped in a brand new MAF from a buddy and that didn’t make a difference.

Replaced 02’s again.

Checked fuel pressure.

Replaced fuel filter

spark plugs and plug wires.




Only thing I thought it could’ve been possibly was maybe my TPS.


Just wanna know if reverting back to the previous parameters in which it ran fine would be a smart move.

kinglt-1

iTrader: (26)

put the old tune back in it and start logging data...if you tune with a mechanical issue then the tune is going to be off when the mechanical stuff is fixed.

cheep

If the fuel trims are that far apart, you may have the O2 connectors swapped.

imagen2k

Replaced my fuel filter again and it seemed to help. Idles now. Still backfires a little if I give the pedal a little love tap.

Fuel trims are still off. Gonna swap out the bank 1 sensor with the other side and see if the trims change


EDIT: new 02 did not help at all.