UpRev ECU tune results for Semtex's Z

Originally Posted by semtex

Okay folks, all is not well. Two things are going on.

First, since getting the tune done, my car is doing something rather strange on cold starts. I start the car, wait my normal 30 seconds for everything to warm up, and when I slip it into 1st and tip the throttle in, there's like this weird dead spot. Gas pedal goes down a little, I start to feather the clutch in (same thing I've done a million times before), and nothing. The rpms just kinda don't go up, then all of a sudden, WHAM, the rpms jump up to where they ought to be and I go lurching forward like I've never driven stick before. But it only happens on cold starts, and goes away as soon as the car has warmed up a little more. Like by the time I get out of my neighborhood and make it to the first set of lights a half-mile from my subdivision, the problem is gone. I can launch as smoothly as always. No dead spot, no lag effect.

The first time this happened was yesterday morning when I left to go to the gym. I thought maybe it was my imagination or maybe it was human error on my part. But this morning, it did the same thing. It even did it when I was done with my workout and left the gym to come back home (car sat for about 2 hours). Something is f'd up. The driveability of my car has been compromised.

Okay, the second thing going on is this. I just got back from my DynoJet pulls. I have LOST approx. 15whp since my last DynoJet pull on the same DynoJet! Check it out. RunFiles 003 and 005 below are from today. RunFile 010 is from back in May.



I know, I know . . . different pulls on different days, months apart, right? But look at the run conditions:



The green and yellow lines are from today. The blue one is from May. It was cooler today than it was in May. Humidity is higher today than in May, but the correction factors should compensate for that.

Take these two things together -- the weird dead spot on cold start, plus the bizarre dyno results, and I think I'm being fair in saying that something ain't right!

I haven't been able to talk to Sharif yet, so I'm not sure what the next steps are. But right now, I'm about ready to have him flash my stock tune back in. This is not the desired result.

Originally Posted by B1nks

Ok well I haven't done a dyno pull on my original dyno but the same exact thing is happening with me as far as cold start drivability. I just had my done by uprev on Thurs. And I'm in Dallas right now and haven't contacted rich cause it's the weekend but I will be. Didn't drive my car again till last night and it did that along with this morning. A little upset but hopefully UpRev will make things right.