UTEC Guru's Help!! ----UPDATED..HELP AGAIN.
 

Ok....we did my UTEC install and tune last week. At the same time I had crawford cats installed (before the tune obviously).

So half way through the tuning/dynoing I get a SES. Its for one of the front O2 sensor heaters. At about the same time.....after doing a 4th gear run, my car stalls after he lets off the gas. The rpms fall and it falls all the way to around 500, sputters, and then dies. The tuner and I look at each other like :confused: . He restarts it......we continue. It didnt stall again.....and we did like 10 runs so I figured it was a result of that.

So we finish the tune. Clear the code.....it comes right back. We decide to see if the SES clears on its own after the car cools etc (it didnt). I was very pleased with the gains. On paper and in the car.

BUT..........as Im driving this week. The car keeps stalling!!! ONLY on falling rpm's. From like 3000 or higher.....I lift off the gas, the rpms fall all the way down to like 550/500 and then sputter and stall.

So today I go back in. We pull the UTEC totally go back to stock ECU. The SES and the stalling are gone. :o BUT so are my gains.:(

I thought for sure the SES was from the cats.....but apparently not.

So my long-winded question is: What aspect of the UTEC/Tune is causing my stalling and what would remedy it?......and more importantly.....HOW the hell is UTEC causing me to throw a O2 sensor heater code??????? Any ideas?

My tuner is talking to UTEC and we will figure it out, but I just wanted to see what ur guys thought were.

THX. :D

PS- Props to Japtrix for working to solve this problem. Gus and Roger are great.:)

First thing do you have the spark plug non fouler mod. If you dont do it. If you do, I would call Sharif at www.forgedinternal.com the dudes a wiz with UTEC.

Are you talking about the O2 sensor non-fouler mod?

The cats are not causing the SES.

Hella, switch your UTEC to map number zero. If the car stops stalling, and runs normally, then you have isolated it to the UTEC settings. If its still stalls in the zero map position, then I would try reloading the fireware. Let me know if that works.

Also, make sure your TPS voltage values are correct. Are they tuning it in open loop fuel mode?

By any chance, do you have a light weight flywheel?

MRC MOTORSPORTS LLC.
YOUR VQ35 SPECIALISTS AND #1 UTEC RETAILER AND TUNER IN THE COUNTRY!
WWW.RACEMRC.COM
732-251-8200
Sales@racemrc.com
AIM: SALESMRC
Authorized dealers for: APS, Greddy, Turbo XS, GT-Spec, Strup, Unlimited Tuning, HeadGames and more.
On site Dyno tuning with our load based Dyno Dynamics Dyno, specializing in Uni-chip, UTEC, Emanage and LS1 Edit.
ASK about our easy and felxible financing options now available for all your automotive and performance needs!

It defiitely is the UTEC settings causing it because when I went back to the stock ecu the problems were gone. (both the SES and the stalling)

He started tuning on map 1...which is the pre-set map for intake/exhaust from UTEC.

Im not sure about the TPS voltage values.:confused:

No.

The only thing I can think of is he was having a problem adjusting the timing. It wasnt excepting the timing he put in. He would make an adjustment....we would make a run.....and in the datalog it would show that the timing had not changed. So he ended up just leaving the timing to the stock ECU.

The SES light is what is so puzzling.

man i cant wait to get a shop setup so i can tune peoples cars correctly.


if you know how to go into the utec and look at the maps, go in there and type the 100% column for your fuel and timing up here and a few of us can take a look at it and tell you if it is close to being correct.


you should be somewhere in the mid to high 12s AFR and two degrees advanced on your timing for most hp...

Do what Sharif recommended,

Put it back in and see if it stalls when you run the car on map 0. If it starts stalling again then you know its not a tuning issue with Map 1. This is because map 0 goes off the stock settings so it might be another issue like firmware etc.

Maybe I wasnt clear above.

We totally disconnected the UTEC. Like its out of the car. Once we did that all the problems (SES and stalling) ceased. So it was the UTEC settings.

So............. my long-winded question is: What aspect of the UTEC/Tune is causing my stalling and what would remedy it?......and more importantly.....HOW the hell is UTEC causing me to throw a O2 sensor heater code??????? Any ideas?

I appreciate any help you guys could give.

Thx!!!

We understand but im not sure you do. Pulling the utec completely out doesnt tell us if it was UTEC tune settings, or UTEC fireware or other UTEC issue.

By putting it back in, set to Zero and you have the stalling issue, then its not the tuners settings in the Map he made in position 1. It must be something else, like firmware or something else.

By putting it back in, set to Zero and you dont have the stalling issue, then you know there is something wrong with the tuners settings with the Map he made. So you would focus your attention there.

^^^Correct^^^
Give the zero map position a try and report back.

I agree, do what Mchapman said. Its just like trouble shooting a home PC. Need to eliminate what you can, to find the problem.

Later
Aceman

Awwwwww........yes I did not understand. :icon22:

Thanks guys Im going to go back in next week.

I will be back.

Ok we ended up sending back my UTEC and got a new one......re-flashed it to finally get it to work.

OK....so now here is my problem. The car sometimes stalls right after I start it when it is warm. Also I feel some peaks and lulls at around 2800-3700 rpm's. What i mean is if im smoothly accerlerating thorugh that range I get a surging. As if Im on and off the gas. Its slight but I can definitely notice it.

Any ideas what is causing these problems?

Sounds like you are getting timing retard do to knock. Also make sure the connectors to the ecu and utec are nice and snug.

Hope this helps

Aceman

It sounds like the ground wire needs to be relocated like TXS said in their other thread. That seemed to solve most problems with the unit.

That surging that you are feeling sounds like you don't have a good street tune. my car has been tuned on a dynapack, but still needs minute tuning adjustments for the street. i get the surging if i'm in 2cnd gear and i'm steady on the gas pedal. ask your tuner about this.

From what I gather is that the UTEC is knocking or there is rough spot in the map. Without datalogs and hard information this is shooting in the dark. I would recommend you taking it back to your tuner, as I am sure they are more than happy to help you with your vehicle.

At the minimal, please ground the UTEC with the 12 pin molex adapter.

Thanks,

Jermaine~