Quick question guys. WE TRIED SEARCHING, but no luck. Anyway, one of my buddies is having a problem with his stock block TT Z. He doesnt have an account, and doesnt really get on the forums, so we are trying to figure out whats up.

ANYWAY, he has stock block TT Z (18g's with open dumps), DW 600cc injectors, Walbro 255lph fuel pump, Crawford plenum, Utec (tuned). Anyway, the tt kit has been on for about a month now, and this problem recently started. He was cruising home, did a couple pulls on the highway, having fun (the usual ) and after about 30 min of driving that one day, got off the exit and cruising home, the Air/Fuel got pinned to 10! RICH!!! At first we thought the sensor, but definitely not. The car seems to sputter a bit, and definitely sounds different. He was having problems with the Map selector switch, and got another one, and it seemed to have worked at first, but nothing. Worked for about 5 min driving down the road, and back to 10! So we tried resetting the ECU, no luck. Tried letting it sit overnight, the next day it would run fine for a about 15-20 min, cruising down the highway, and BACK TO 10! It would run fine for a couple minutes and then get rich! It runs RICH at IDLE and cruising, basically anytime your foot is on the pedal. The only times it runs lean, is in gear with the foot OFF the pedal. The rest of the time, RICH! So anyway, he waited one more night, went to work the next morning. Cranked it up, and even cold start it was pinned at 10! So HOT and COLD starts, it runs RICH!!!!

ANY IDEAS???

 

did you check for any codes? maybe the Crankshaft or Camshaft POS Sensor ... my first thought was maybe it was the UTEC temp correction.. but you're not in boost so it should be the ECU under full control.. i would get an ODBII Reader from advance autoparts (up here in CT they will let you take the reader if you leave your license) and see if the car has any codes

 

The only code is P0300. We tried that too! LOL! Which is cylinder misfire, but that seems to be common on any forced induction cars....

 

anything change since it started happening? weather? tempreture? can you get into the UTEC to make sure injectors are scaled? i think i remember some one saying something about 0 in the fuel column?

 

Nah, nothing at all changed. Out of nowhere. It was just tuned not too long ago, like a month ago. The only thing he would mess with, is the map selector switch, but nothing else. But no, we dont really have access to the Utec.

But if there was a 0 in the fuel column, wouldn't it happen all the time? Instead of only after driving it for a couple minutes? That one cold start just happened today on his way to work this morning. But he said it was fine on his way home. (he works only 5 min away from his house)

 

well i was just wondering if the tuner had set it up that way to begin with.. are you guys in GA? maybe you can have sharif take a quick look.. maybe quick diagonistic fee is worth the headace

 

To where it would run rich after awhile of driving? Well, for about the first 3 weeks, car was fine, not one problem. And this recently happened, like 2 days ago. And we have been doing research since....

 

Any other thoughts, ideas, beliefs??? LOL!

 

Log on utec, pull out his fuel map Edit: (Just read no access to Utec). Does he running RFS? and how much whp he put down? I'm just guessing it is fuel problem. No matter what he needs to take it to tuner adjust Utec or retune it.

 

Its probably the factory o2 sensors going bad and its overcorrecting it to run rich. i would start by replacing them in the manifolds. Could also be a factoy MAF with some dirt on it but i would try the first one before i messed with the MAF.

 

RFS? He put down 410rwhp on dyno dynamics So doesnt sound electrical?

 

O2 sensors can do that?

 

well since its pre-UTEC .. that means the ECU is controlling the car.. so you have to think of all the things that the ECU uses that will affect the A/F Mixture to make it run rich.. Factory 02 sensors and MAF are a few.. though its pretty weird you're not getting a code yet.. usually when the 02's start going the code pop's up real quick

 

My car has been doing the exact opposite.
Only at idle, my car leans out & sputters here & there.
No codes here either. It makes it frustrating.

 

The car's supposed to run lean at idle - around 14.7-14.8'sh - so if it's right there, that's completely normal. As for the sputtering... maybe your idle RPM is set too low?

 

Return fuel system. I'm not a tech but I know lot of fuel can makes car runs richer, which I'm guessing 600 injectors is little big for just over 400whp turbo car without rfs. And He is getting no code..

 

o2 sensors on yours too. Probably actually air flow meters used in the late 04s and up. They tend to go lean, then correct themselves, then go lean, then correct themselves, ect.


The o2 sensors actually can correct 25% all the time, plus another 25% on top of that if needed. So they can cause it to run really rich or really lean.

 

Hey guys, my buddy created an account, and will be joining soon (Zphanatic)

Anyway, if o2 sensors were bad, like mentioned before, wouldnt it throw a code? Same with the MAF?

 

That's good to know jt.

 

Hey man, no I dont have a fuel return system...

Oh, and no code either. Funny thing is, when its pinned at 10a/f (rich) is when the check engine light comes on. And I checked it then, and it was P0300, which is cylinder misfire. And that seems to be a common code with cars that have forced induction.