Hey guys, I've been trying to sort out my low k27/6 dyno stuff for a while now.

No vac leaks, no more exhaust leaks...

I had the car at the shop that did the turbo and refreshed head on the car. After several test runs and speaking to Josh(rogue) we think that the FPR is going bad.

No matter what boost I set from 12-18psi my AFR hits high tens once full boost hits. The shop put a FPR gauge on and I'm reading 43/44psi at idle which seems correct for the 3bar FPR, but on boost, the gauge is reading about 4 psi more than the 1:1 ratio.

The one run that I saw myself was at 17psi, and the FPgauge showed 65/66 psi near redline instead of the expected 61psi.

FPR bad?
Fuel Pump going bad?
Both?

 

Might help to post a log of the afrs through the rpms.

4psi isn't going to make or break it , but if it's already rich it could add to the problem.

 

How accurate in the FP gauge? Have you checked the fuel return line under the car to make sure it is not damaged causing a restriction and acting as a second FPR?

 

I can't log till Josh finishes up with his logging stuff.

We were just going off the fuel pressure gauge taped to the windshield.

 

I'm going over there tomorrow we can check the fuel line then. The gauge... I have no idea, it is what ever they use in the shop. Comes in a big case with lines.

 

I was getting very similar results with the M-tune on my car, fuel pressure checked out fine but I was seeing high tens under full boost.

 

Thanks for the info. Did you change the fqs settings to adjust?

 

Zeff,
What FQS setting are you on currently?
When you say it has 43/44psi of fuel pressure at idle, is this with the vacuum line on or off?

 

Josh this is still on the 0 setting, we're gonna do the other fqs stuff tomorrow.

car was 43/44 psi with the vac ON, car did 48psi with no vac.

 

Yep - typical fuel pressure being too high... I am quite amazed at the (lack of) quality control regarding fuel pressure regulators.

A 3bar regulator should be 43.5psi with the vacuum line off. That much extra fuel pressure is worth a ~0.75 or so change in AFRs.

Switch to FQS position #2, to help take out some of the extra fueling caused by the excess pressure.

 

We're doing that tomorrow. I was having dme issues when I tried it before and the afr was like 12.5 on boost.

 

Seems like the FPR is getting worse, car was reading around 10.2 on boost then after switching to FQS 2 it came up to 11.0.

 

Ok guys, no more input? Should I go with another 3bar or an adjustable?

 

An adjustable will eliminate the problem on incorrect fuel pressure, and give you some more adjustability...

 

Thanks Josh. I know the mtune uses the 3bar, is there a specific target fuel pressure you recommend with an adjustable?