Z06 tuned with edit problem
Z06 tuned with edit problem Hi all. Just bought a 2001 Z06 that has a few mods. 
It has been tuned with edit and runs and idles very well, except just after filling the tank. It is like it has to relearn the idle after every fillup? What causes this?
It has been tuned with edit and runs and idles very well, except just after filling the tank. It is like it has to relearn the idle after every fillup? What causes this? 
TECH Regular
Joined: Nov 2003
Posts: 434
Likes: 0
From: Dallas
Here's one theory for you...
Opening the gas tank affects the evaporative purge system. When you replace the gas cap, there are gasoline vapors trapped in there. When you restart the car, the evap system has to pump the vapor out through your intake manifold. This affects the idle and fuel trims for a few minutes until the evap system has done its job.
Opening the gas tank affects the evaporative purge system. When you replace the gas cap, there are gasoline vapors trapped in there. When you restart the car, the evap system has to pump the vapor out through your intake manifold. This affects the idle and fuel trims for a few minutes until the evap system has done its job.
Teching In
Joined: Dec 2001
Posts: 387
Likes: 0
From: Southern IN, USA
That SHOULDN'T affect the idle! It could be a number of things, but it SHOULD be setting or throwing a code if it is powertrain related (and a fault in the EVAP system certainly would!)
Could also be dirt, abuse, something out of adjustment, a part ready to fail...
Suggest a more comprenhensive diagnosis before proceeding. Good luck!
Could also be dirt, abuse, something out of adjustment, a part ready to fail...
Suggest a more comprenhensive diagnosis before proceeding. Good luck!
Last edited by emarkay; Mar 16, 2004 at 10:19 AM. Reason: spelling
TECH Regular
Joined: Nov 2003
Posts: 434
Likes: 0
From: Dallas
True, the evap system doing its job shouldn't affect idle.
I have logged the fuel trims changing several times immediately after a fill up. They go large and negative for about 1-2 minutes, then settle back down to their normal values. I'm close to stock, so I really didn't notice any idle quality change.
I was guessing that the brief period of richness might be more noticeable on some cars, depending on the mods.
I have logged the fuel trims changing several times immediately after a fill up. They go large and negative for about 1-2 minutes, then settle back down to their normal values. I'm close to stock, so I really didn't notice any idle quality change.
I was guessing that the brief period of richness might be more noticeable on some cars, depending on the mods.
Originally Posted by deezel
True, the evap system doing its job shouldn't affect idle.
I have logged the fuel trims changing several times immediately after a fill up. They go large and negative for about 1-2 minutes, then settle back down to their normal values. I'm close to stock, so I really didn't notice any idle quality change.
I was guessing that the brief period of richness might be more noticeable on some cars, depending on the mods.
I have logged the fuel trims changing several times immediately after a fill up. They go large and negative for about 1-2 minutes, then settle back down to their normal values. I'm close to stock, so I really didn't notice any idle quality change.
I was guessing that the brief period of richness might be more noticeable on some cars, depending on the mods.
Ill try just removing/replacing the gas cap without refilling and see if the same thing happens... 
