HP Tuners part 3

Redog · 04-01-2012, 12:15 AM

OK I'm getting effing pissed off doing this shit over and over again and it's going one way, then the other, then back again.

So the car was running fine, but it's not perfect and I know that the MAF scale is NOT within the 1% is has to be. So I drive for 15 minutes, then start scaning and drive for another 15 and I get this in my MAF scale. Flash it into the car, and the car runs awesome. However it was NOT within the 1%

So I scan again, all the numbers after this scan are a lot higher than the 1% mark. I put them in the car and guess what, the fuel trims are backwards AGAIN!! WTF!!

Scan and drive a third time, get decent numbers in the MAF scale, so I burn them to the car and the car runs really good for the 4th scan. Seemed to be leaning out a bit at some points of WOT, but nothing like the scan before that.

So I'm scaning the 4th time after getting decent numbers from the 3rd scan, the numbers are a little bit better, but they were also a little bit better after the 1st scan, so I DID NOT transfer this scan into the car. I just turned the EGR back on and posting this here to see if anybody can tell me what I'm doing wrong

Both the scanning and tuning programs are in Imperial. It was suggested one was in Metric.

This is driving me nuts.

WhiteV6 · 04-01-2012, 11:10 PM

We have been dealing with that on the test car, but I found the issue, and recently, the cause! Gerson is running an adjustable FPR with the AN lines and all. The lines are routed between the exhaust, and the coolant line. When the gas gets hot, the pressure drop 5+ psi. That will mess up a tune every time.

Check your fuel pressure and see if its the same on cold start and then again after the car is fully warmed up.

What plugs are you using?

I had an issue with the cavalier where the EGR was turned off, but it was leaking. I cleaned it up blocked it off, and that fixed its intermittent stumbling and cold start.

Basically, unless you are comparing cold start to warmed up tuning, you likely have some physical issue.

Redog · 04-02-2012, 12:52 PM

Hmmmm. I did notice that the car was heating up a lot during tuning, I mean a lot. My temp gauge went upto 1/2 way during the 3rd scan.

I'm running stock ACDelco plugs. Don't know which part number off the top of my head, but I do know they are stock for a 2000 LA1 motor

Could I just buy a small fuel pressure gauge and put it on the testing port for long term? I'll buy a small gauge and an AN elbow and leave it there

WhiteV6 · 04-02-2012, 01:55 PM

It isn't good to leave it on the shrader valve all the time, but you can leave it on for a day to check. All you really need to do is check it cold start, pull the vac line to the regulator, check it. Then drive it and when it gets to full temp, check both again. Pulling the vac line isn't really necessary, but its simple so I do it.