Well I just finished my built for my 03 350Z last month. Broken-in and oil change as the shop that built my engine recommended. Everything was fine. The car runs great. Tuned with 2 maps, one at 14psi and another at 21psi with water/methane using a Utec.
So yesterday I took the car out and driving it around town with no problems at all. It only has 1/4 tank of gas left so I pulled into Sunoco and filled up with 93 octane. After filled up, the car started fine and then after 5 seconds it started to stutter and shut down. It keeps happening like that. If i stay on the gas then it wont shut off. I looked at the A/F and at idle before it shutting down range from 11 to 12 A/F. I left it overnight and came back with the same problem.
Could it be bad gas? Or something is wrong? Please help!!!
Spec:
Fully built long block with head works(Tomei cams)
CJM stage 2
Triple carbon plate clutch.
3.3FD
Greddy TT kit.
Greddy catch can.

 

Well even if its low octane, it shouldn't give trouble with no load. 11-12 is rich under vacuum but not enough to stall the car I don't think. You could try to drain it - hopefully it's not diesel or some screw up like that...

 

21 psi on 18g's, WOW!!!

Back on topic, yep, I would lean toward bad gas. Happened to me. However, with it shutting down like that, it has to be the partial throttle in the tune. I never could get my car to run right after I built it using UTEC. Fair warning, sell the UTEC and go to a stand alone when you are built.

UTEC is awesome with stock block under 10psi, but not so great with built pushing 600 whp and beyond.

Sorry for the wrong post. Its either bad gas or bad tune.

 

I know I shouldn't go with the Utec. But after everything is done....I'm totally broke. I will upgrade later on. As for the problem, I found the answer to it. While i was pumping the gas, my wife was messing around with the Uteci map switch and put it in map 0 which is nothing on it I switch back to map 1 and everything is fine *WEWF* Thanks guys.

 

I did 19psi on greddys with the utec for a year and no problems.

 

I have had that happen to me as well. Glad it was simple.

What did 21psi net you?

 

No dyno yet. My tuner just did the street tune for those 2 maps. I still have to switch to synthetic oil and change my plugs soon. I read on here that 21psi is the max the 18Gs can do. But my tuner said that at 21 psi my car still pulling very hard til redline with the help of methane kit. I will get it dyno soon though. Pretty busy with work and life.

 

21psi is fine for the 18gs, but I wouldnt go much past that.

 

Sounds like your wife needs a spanking for messing with your toys ....shame on her.

 

amazing he knows that without a dyno.. must be his butt dyno

 

A 21psi street tune...damnnnnnnnnnnnnnnnnnn

 

You only live once!!!

 

data logging with his laptop He has been tuning many high power cars like that for a while. He used to have a dyno but sold it. Now people from other states and Canada still bringing cars to him to tune. So I guess I can trust him with my car. I won't be driving the car much until I switch to a stand-alone system and bring it down to Sharif to get tune. Winter is around the corner right now so it will be in storage until next season.

 

without a dyno he can't really tell if you are still making power to redline

 

With data logging to include G-forces, it's possible to get a great road tune, traction issues aside. But how can you road tune 21 psi by yourself? No traction in low gears and definitely not safe traveling a mile a minute in high gear. Suicide... OP, did he take you along to road tune?

 

He brought his mechanic along with him which is also my friend. That's why I want to get another tune by someone like Sharif on a dyno before I beat on my car. For now, I just drive it normal and not getting into boost much. Driving with the new triple carbon clutch is pretty tough. I'm just getting used to it a bit now.

 

His friend, my mechanic, drove the car. He's had Vette's and driven plenty of high HP cars. We stopped tuning and told Pat that to go further we'd use a dyno.

I use airflow and my Driftbox, plus accurate vehicle weight to determine relative output using G's and the high speed GPS data. This tune was just for Pat to have some fun with the car until he wanted a little dyno time to finish it off.

My mechanic and I drove about 30 minutes to Pat's house last night to find out why the car was acting up. We got there and the UTEC switch was on zero (stock mode). Flipped it to position 1 and the car is fine.

 

Thanks for the clear up Mike Will hit the dyno when we get time. I'm grounded at work 7 days a week now. Just had one of the Chef quit suddenly. It's really sux.

 

OMG!!! You totally need this sticker!!! Haha~ I have one... and my wife abides by it~~ +1 on the full standalone EMS.. I love my f con v pro...

 

+1 on the sticker