So this is the new story. I was having drive-ability issues and my AFR's are bouncing like a huge pair of **** on a 10k run. They were going from 17.0 - 10.0 - 17.0. I thought that the tune was the issue so I got some updated stuff from Vince and datalogged it 3 seperate times. He says that the fuel trims are on.

I had a buddy come over with his scanner and say that the O2 is flat lining.

I changed out the O2 sensor and the MAF. When I am giving constant throttle at 2500 rpm, The AFR's will be between 14.9-15.2. After about 5 - 10 seconds the rpms will fluctuate about 300 - 500 more and settle back down. My foot never changes position. Still, I am watching the RPM's boucing from 15.2 - 13.6 -16.0 - 15.2 I am now really confused.

To add, I redid all the piping to make sure it wasnt a boost leak.

UPDATE: I found it. The forge bypass has a little baby o-ring when you take out the spring. We sealed it up and the leak is all gone. I'll submit pics soon.

 

im having the same exact problem...sub'd

 

I dunno, but I wanna hear what it is tho

 

Me too. This had been going on for about 2 weeks now and I raced a fully bolted tuned STI before this all happened and he stuck with me the entire way so I know something was wrong.

 

Your intake is a K&N Typhoon - you can have problems with it screwing with the incoming airstream, as well as oil coming off a fresh filter install messing with the MAF. Try clocking the filter around to see if that fixes the values - or just for shitznengiggles, see if "socking" the filter with a light bit of very breathable cloth (not something that'll choke the airflow! If you have an "offroad" sock for filters that would be ideal) stabilizes the numbers. If it does - you know your CAI needs tweaking.

 

Ill try that. Thanks.

 

to add, im having the same problem and i have a filter directly on the turbo with a MAF relocation.

 

This sounds like its common. I wonder if there are more than just us. What tune you on?

 

HPT, 26psi, 91oct...so really conservative

 

K, I'm on Trifecta, 24psi, 91Oct - maybe 93 since this is Illinois but ill ask.

 

Just a guess-maybe a vac line leak or something not snug on the Forge unit?

 

I have looked for vac leaks everywhere. What do you think would be the best way to inspect the forge unit? I do have a weird issue that sprung up a while ago and I had people say they had the same issue that this was normal. When I get to a stop sign and pump my brakes, my AFRs drop into the lower 16 - 17s. I totally forgot about that.

 

do you have a good 6in before and after the maf? It might be messing with it.

 

K&N only has about an inch to the filter.

 

I had a bouncy idle problem a little while back. Turned out to be a corrupt HPT file. I flashed an old one and it ran fine until I could get a fresh new updated file.

Maybe try that?

 

Hmmmmm I have no way of monitoring my afr's but I do feel like my tune is a bit off.. I say that because, I have an intake, dp, full 3in exhaust, tr8 intercooler, trifecta 24psi tune and my buddy in his balt trifecta tune @23psi, intake+dp still pulls me by like 2 cars

 

It really does sound like a vac leak. Purge solenoid, maybe? Unplug it and see what happens. You'll get a code for that, but see if it runs better.

 

^ YEP..... unplug the evap purge and see how it acts.... it can raise hell with the LTFT's if its going bad . Your trims will zero out when the evap purge is unplugged ......just a heads up so it doesn't freak u out .

 

I found it. The forge bypass has a little baby o-ring when you take out the spring. We sealed it up and the leak is all gone. I'll submit pics soon.

 

damn..i was hoping you would say it was the purge solenoid lol cuz im going to try that in the morning when i get off work. hopin that solves my idle problem

 

Here she is....the little bastard.

 

Good find. Tough one, there.

 

Ive been having the same issues. Huge AFR fluctuations. Going from like a normal 14.2-15 suddenly dropping down to like 9-10, then bounce back up to around 16+. I unplugged my evap sensor and bam, afrs normalized.

 

Do you unplug the harness or the actual plug/sensor?

 

Glad you found out what the problem was