Noob Tuner Needs Help
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.
Last edited by imagen2k; Sep 8, 2019 at 01:26 AM.
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.
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.
Last edited by imagen2k; Sep 8, 2019 at 04:52 PM.









