High Idle Fuel Trim

**Tehnation** · #1: 03-23-2013, 04:02 PM

Ive been looking all over for vacuum leaks, found one but my learning view still pegs at 15, any ideas??

**Tehnation** · #2: 03-23-2013, 04:42 PM

Car runs and pulls fine. Anyway to get turbo inlet hose out and in without removing intake manifold?

**Tehnation** · #3: 03-23-2013, 05:08 PM

Wish my car had a face so I could punch it.....

**Custom Trendz Inc.** · #4: 03-23-2013, 05:48 PM

I recommend plugging the FIRST nipple on the turbo inlet and leaving the rest on. Then pressurize the system and check for leaks. Just dont go crazy with 15+psi(do 10 at most.)

Ive been chasing down a vacuum leak for about 2 weeks now :/

**Tehnation** · #5: 03-23-2013, 05:56 PM

Tried something like that, and found one hose, but after that nothing. Will be replacing intake manifold gaskets when I remove it to inspect turbo inlet hose.

**Custom Trendz Inc.** · #6: 03-23-2013, 06:31 PM

Ok good luck, i also found one breather hose that leaked and now no leaks, holds pressure but still messed up fuel trims.

Sent from my DROID RAZR using Tapatalk 2

**Tehnation** · #7: 03-24-2013, 01:20 PM

... Everything was fine. Cant seem to find this leak, its supposedly a big one. But I cant find it anywhere. Anyone any ideas? Pulled off intake manifold, took everything apart. Idles fine, runs fine.

**Tehnation** · #8: 03-28-2013, 06:49 PM

I made a boost leak tester, fixed all the leaks, zip tied every hose, and now its completely silent under pressure. Still have high idle fuel trim. My maf is peaking at 208 g/s. Going to change air filter. Already took a bottle of maf cleaner to maf sensor. If air filter does not raise g/s I will replace maf.

**rhino6303** · #9: 03-28-2013, 08:57 PM

I can't see if you mentioned but do you have the stock air intake system with snorkel and stock turbo inlet?

Any change in these can also affect the fuel trims/Maf data.

**Tehnation** · #**10:** 03-29-2013, 07:49 AM

Stock everything except crank pulley, flywheel, uppipe and downpipe for engine stuff. Going to pick up fuel pump/vacuum tester to test fuel pressure. If thats good then I will purchase a maf.

**Spec B** · #**11:** 03-29-2013, 08:01 AM

Can you post a learning view of the F'd up fuel trim? How much correction?

**Tehnation** · #**12:** 03-29-2013, 08:25 AM

In a class atm but the idle trim is at 15 and 3rd box is at 7-9 the other 2 are 1 and .something. lemme find post of old lv.

**Tehnation** · #**13:** 03-29-2013, 08:28 AM

Quote:

Originally Posted by Tehnation

Looking for a leak, checked all the normal spots. Any ideas?

With these numbers if it were a vacuum leak it would be a hose completely off. But When I cap up the turbo inlet and put it under pressure, I dont hear a peep. Zip tied everything, replaced turbo inlet hose, and maf sensor hoses and it holds the pressure for a long time, but I am getting the same numbers. If its a leak it would be small but it shouldnt throw it off that much I would think.

**Spec B** · #**14:** 03-29-2013, 09:29 AM

Hmm..assuming your maf scale was solid before this craziness, you should log you front O2 and confirm that no odd readings are popping up. I am leaning toward a O2 or maf sensor issue.

It might be you maf scale was never really perfect..

**cryo** · #**15:** 03-29-2013, 12:06 PM

Quote:

Originally Posted by Spec B

Hmm..assuming your maf scale was solid before this craziness, you should log you front O2 and confirm that no odd readings are popping up. I am leaning toward a O2 or maf sensor issue.

It might be you maf scale was never really perfect..

I am leaning twords a 02 or maf as well.

Ive seen cars needing some tweeks for slightly higher that normal af learning but this is 100% stock maf scaling and stock box.

Dave