I was riding with a buddy Sat night in his G35 with the T-netics stage 1 kit. The car went into limp mode twice. The car has the stock reflash with the UTEC installed but not tuned yet...only zero values. UTEC clamps at 4.7 volts but we were still hitting limp mode. "overboost cut" has been mentioned by some forum members. I have not seen this before. Anyone care to fill me in??

 

if the utec is installed but not tuned, it should be set to map "0" which lets the ecu fully control the car, and that shouldn't be happening.

 

How much boost is he seeing at the manifold?

 

It's going into limp mode because both the short and the long term fuel trims are maxing out. This is the reason. I have had that issue, before scaling hte injectors properly. I don't know quite how to do it on the utec yet.

 

8-9 lbs on the gauge off the manifold. Temp was around 65 degrees at the time.

 

Hmm, no boost leaks anywhere?

 

That's the situation. All values on the UTEC are set at zero and the car is essentially running off the flash. The clamp on the MAF voltage on the UTEC is 4.7 volts. This is why I think this is so strange.

 

Everything is tight. Holds boost perfectly. It just hits the wall around 4000-5000 rpm and it's game over until the car is shut off for a couple of minutes. Earlier in the night it was fine....then did it twice in 20 minutes.

 

I haven't heard of this on the stock reflashed ecu's before. Anyone else seen it??

 

It is your MAF. The stock mass air flow sensor can not handle the heat. It is a bad design on Turbonetics part. The hot air is going right past the sensor and it will cause that. It happend on my car and after about 3 days of talking to people I figured out exactly what it is. The MAF are expensive around 350 if i remember correctly. I had it installed and fixed from a local place called uprev in Austin, TX. After getting the new one in I have had no problems, but they said it will only be a matter of time because the hot air is what is killing it so it will work for a while but then i will have to replace it again. They are going to design something up so I will not have to use the factory MAF.

 

the design of the TN has nothing to do with the MAF going bad


I've been driving hard in FL heat and humidity for 12k miles, and my car runs just as good as the first day I installed the kit.

It's not the MAF. He's got something set in the UTEC that shouldn't be. If he's set on map "0", the settings in the other maps have absolutely no bearing on how the car runs.....so he must not have it set on map "0".

 

Actually yes, I would bet it is the MAF, I had the EXACT same problem about a month ago. Replaced JUST the MAF, NO problems at all. So tell me where any tuning made a difference with my car going into limp mode. If someone is using a UTEC and still has the MAF sensor in use then eventually they will have the problem. Mine happened at around 35k miles another friend, solidsnake, which has the TN kit as well, had this happen to his car. Two options, get a new MAF sensor it will work fine for a while, but this will eventually happen again, or find a way to not use the MAF. I would suggest setting up the Map sensor for the UTEC.

 

I'm still thinking the UTEC is set on a map number and it's cutting injectors or ignition or causing a maf issue, i don't think his MAF is bad.

 

And you don't think its possible the MAF was damaged during install. I have 35k+ miles on my kit and have (a)never had this happen and (b) still running the stock MAF. I have no heat wrap on any of my piping and anyone who lives in Socal will confirm its been 100 degrees or higher lately. BTW those 35k+ miles include trips to the track, full boost pulls in 105F weather at BOTI last year, etc.

 

G356gear post what fixes it after he gets it fixed. I know we talked on the phone a little while earlier about the issue. Everyone wants to say it isn't the MAF, but I know I had the exact same problems and that is all it took to fix it, no problems since fix.

MIA do you actually still use the MAF? or do you have a MAP sensor for the UTEC or something similar. If you have a MAP sensor or are using something other than the MAF then that is why you do not notice there is a problem.

Why is it so hard to believe that The Turbo forcing all the air past the MAF could cause this problem?

 

I don't doubt the MAf may have gone bad or may be going bad. And I don't have a UTEC. I have been running the out of box Stage 1 kit with the relfash, original MAF, in fact original everything except clutch for 35k+ miles.

 

because it would have happened a LOT sooner. MAF's are much, MUCH more sensitive than you think

 

One thing I haven't seen mentioned is the voltage clamp setting. If you clamp it lower what happens? Sounds like the MAF is going over voltage and may not actually be bad...

 

These 3 cases seemed to happen within 1000-2000 miles of the turbo install.
MAF was fine prior to that. If they were damaged during the turbo install I would have expected to see failure right away.

 

I don't think it would be a good idea to clamp much lower than the max MAF voltage for the ecu. I would expect problems with the fuel tables on the re-flash if you clamped it lower....at say 4 volts. I understand anyway that the UTEC does not allow changing of the MAF clamp voltage by the end user. This would require a reprogramming of the UTEC at the manufacturer level.