fuel trims

**RealLiveMD** · 08-18-2009, 09:49 AM

After a lot of searching. I finally found a vacuum leak in my H/C car. The problem is that my car had been tuned before i found the vacuum leak. I took it to a friend of mine at the dealer after finding the leak and he set all of my fuel trims back to factory default. I was a little worried because I thought that the trims were part of the tuning process. He said that the computer would relearn what it needed. Now my car is running superrich. What's going on? Do I need another tune now?

**0rion** · 08-18-2009, 05:10 PM

the short answer is yes...you'll need another tune.

**RealLiveMD** · 08-21-2009, 10:11 AM

Originally Posted by 0rion

the short answer is yes...you'll need another tune.

Did deleting the fuel trims destroy the whole tune or just the idle a/f ratio. The car drives fine, but then again its a baby cam.

**0rion** · 08-23-2009, 05:51 PM

clearing the trims shouldn't effect anything. Tuning the car with a vacuum leak is the root of the issue. The trims will learn regardless but if your fueling tables were put into place when there was a vac. leak then they'll be off and the trims might not be able to compensate for it. Best bet is to get the car logged and see where it's at. "Super rich" isn't something you can diagnose with your nose. You'll need a data log to actually see what's going on with the car.