TorqueForDays

Hello everyone - in February I picked up my 08 Z06, couldn't be happier with it! A Corsa axleback was installed by the previous owner, sounds awesome.

I recently installed some Stage 4 AHP heads and the car drove great. Not long after I installed an Airaid intake as well! I started getting "Service Traction System" on the dash and eventually a Lean Fuel Bank code on both cylinder banks at idle.

Observing the fuel trims, my LTFT at idle is +24.2% which from my experience is huge! Under partial load, cruising, and WOT... everything is peachy and no codes or very high LTFTs.

Ive done a ECU reset by pulling the negative on the battery and drove a few hundred miles. No change.

What seems to to be he problem? Too much flow? Should I swap the stock intake back on? Do I need a tune to run with the Airaid intake?

Thanks CF Members

American Heritage

Looks like you have a vacuum leak.
You can turn the car on, let it idle and then spray around the intake and tb area with brake clean. When the RPMs pickup/change you have found your vacuum leak

http://www.americanheritageperformance.com/

Dan_the_C5_Man

Classic symptom of air entering the intake after the MAF. And the reason why it has more impact at idle vs. WOT is that a small leak is a greater percentage of air volume at idle than it is at WOT.

heavychevy357

This happened to me. I was getting this code after I did my valve Spring replacement. I didn't notice when I bought the car that there was only one band clamp on the silicone coupler connecting the CAI to the intake manifold. So I went to Home Depot and bought another band clamp.

Also I noticed whoever tightened the clamp last had over tightened it and linked the CAI. So even when the clamp was on tight there was a slight > in the side of the CAI. I warmed it a little and used my hand to smooth it back out.

so smoothing out that kink/bent in portion of the CAI and putting the second band clamp on fixed the problem. Haven't had the code pop up since. Approx 500 miles since the fix.

Point being.. check for a vacuum leak.

EDIT**

This had nothing to do with the valve spring replacement.. was just saying that is when I noticed the missing band clamp which then lead me to find the pinched in CAI tube

Michael_D

Did you recalibrate the air models; MAF / V-VE???

dart.deanda

OP, please let me know if you get the STS message fixed and how. I have one too. I also have a P0106 since heads and cam swap. I'll be looking for a vacuum leak tonight. Cheers!

ChevyCobb

Doing the DIY paint can smoke tester made things so much easier for me when looking for a vacuum leak.
Made my tuner have an easier job as well.

TorqueForDays

Checked all the connections. Nothing was loose or installed incorrectly. Gonna swap the stock intake on this weekend and see if it helps.

Michael_D

Once again, did you recalibrate MAF and VE after the heads were installed? What about MAF after the intake was installed? Need a starting point here to rule out tuning......

A common source of a vacuum leak is that little hose that goes to the stock exhaust solenoids. After installing the Corsa mufflers, this hose needs to be capped. Either at the intake, or back by the mufflers.

But to have LTFTs that far off, I'm leaning towards the MAF transfer needed some tweaking.

TorqueForDays

I'll take a look at the exhaust vacuum lines. Mufflers weren't installed by me so I'm not sure what is wrong back there.

No tuning has been performed.

Michael_D

I would expect to see trims off after any port work is done. The addition of the intake isn't helping.

First, verify you do not have a mechanical issue (leaks), then consider getting the thing recalibrated (tuned).

TorqueForDays

Had some time this weekend to diagnose the car. Turns out I had 2 vacuum leaks: First leak found was a tear in the brake booster grommet. The second leak was at the back of the intake manifold, where I did not cap off the small port that provides vacuum to the exhaust flaps.

Replaced the grommet, and capped the port and all problems were gone! Thanks CF members!