Background on the car.

03 G35 coupe
88,xxx miles
5AT
Vortech SC
TurboXS UTEC
supporting mods (walbro, 440s, exhaust, etc...)
Car has been street tuned, still ran a bit rich under medium throttle

Took it to get dyno tuned today. The car was strapped down and a quick run was done w/o any measurements just to make sure the straps were secure. Car was shut down to cool down a bit. Car then wouldn't start. It cranks over real strong, but it doesn't fire up.

The cars "AT Check" light flashes 16 times. According to tech specs its something about the speed sensor. We tried to hook up an OBD reader and we're getting a read error. When the key is in the "on" position, the fans automatically kick on and stay on.

I spoke w/ a few tuners, including Mark over at SGP who was frickin awesome. He said there was a bus read error or something to that effect. Something is throwing off the electrical communication within the system. We checked all fuses and everything seems to be just fine. No blown fuses. We reset the ECU by the pedal method, disconnecting the battery, and attempting to clear w/ the OBD diagnostic tool. The "AT Check" light is still blinking. Tomorrow we will try to get a hold of a Consult to read the code.

Does anybody have ANY experience in something like this?

 

Worse case scenario from what I can see:

- fried my ECU somehow
- something in my transmission got damaged (flex plate, speed sensor, etc)

There is a third fuse box/relay box behind the drivers side battery that we did not check. I remembered about it late last night, so I'll have them check that today.

 

hmmm... Let us know what you find man. Good luck!

 

The car is fixed!!!

We had almost given up hope. I was calling around to get towed to the dealership, when a 350Z with UTEC came in to get tuned the next day. The SAME EXACT thing happened to this auto 350Z. So with some deductive reasoning the shop was finally able to determine the common link between the two cars. The USB cable used to connect to the UTEC was slightly damaged/crushed. This caused a short when connected to the UTEC, which blew a fuse in the box behind the battery. This threw off the electrical communication within the vehicle. A call to TurboXS helped determine which fuse it was. The fuse wasn't visibliy blown, but replacing it corrected the issue.

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Special thanks to Mark @ SGP who actually called me yesterday morning to see if I had figured it out. He then said he was going out of town for thanksgiving and would take my contact info with me to check in, and he'd call me again on Monday if nothing had been resolved. I have never had my car worked on by SGP, but had been referred to them by several friends who have had their G35s tuned there. He was extremely helpful in lending advice and suggestions on how we could diagnose the problem. Thank you again Mark.

 

I was just about to suggest that your ECU/IGN fuse was blown.

Just for reference, anytime you turn the ignition key on, and the fans come on, and your CEL is OFF...tells you have a blown fuse, or something is unplugged, or shorted. Shorted usually blows the fuse, so its all related.

Glad it was an easy fix.

 

and that's why shariff is the man!

 

Yeah Mark @ SGP told me about if the fans kick on and stay on. Glad it was an easy fix. Now I have to find my boost leak. Only hitting 5lbs and putting down 300whp.