So last thursday i was driving at a very high rate of speed for an extended period of time, 140mph+. Engine was doing fine, had no problems, temp was fine, oil pressure was fine. I looked down and noticed my Check Engine Light was on, and the gear indicator LED was blank (it's a 5AT). Pulled over and there was a lot of smoke coming out of the hood, and the car would not start again. Took it to the dealer the next day and they said that the ECU went into failsafe mode because i was going too fast... Is this true? Does the ECU do that in stock 350z? This is the 05 touring. And if thats teh case, what caused the large amount of smoke? When i got home i noticed a lot of oil on the ground, however there is no leak so i'm guessing some oil spilled out and spread across the bottom of my car, maybe buring on the exhaust system and causing the smoke. What do you guys think? The car runs fine now, but i'm out 100$ to get that damn Check Engine Light taken care of.

 

That is kind of strange.. I mean the part about the oil spill or something that caused the ingine to smoke and then you say now it`s OK. As far as the ECU shutting down the ingine? not sure, I think it will shut it down when you exceed 158 mph.I had my Z at 148 mph (not for a long period though) roads around here won`t let you do that. If the ingine smoked that is usually a sign of some serious ingine damage. If I was you I would have that looked into.

 

It's possible that it was the ECU. How did they know how fast you were driving?

 

It'll go in "limp mode" to protect itself when it senses something is wrong. Whatever caused the smoking caused this, not you just moving fast.

 

Ummm, i've never read that in the service manual. Smoking should not be triggered by the ECU. Leaking oil is not triggered by the ECU. I'd say something overheated probably due to the leak you noted. Check all fluid levels including tranny, power steering, etc.

 

Yes the ecu can go into limp mode. I say there is some other damage to the engine. Most likely an oil leak somewhere.

 

Dealer can check data record/logs (including recent speed) i believe on a stock ecu. Smoke coming from your engine is definetly not a good thing.

 

Yeah this happend about a week ago and no oil leak at all. Engine runs fine, all fluids are fine. I dont know what caused the smoke, but it has not occurrred since. And yes, the stock ECU will report in real-time exactly how fast i was going, and my RPM, along with fluid levels and stuff, that part was actually pretty cool. FYI, that is how they void your warranty if you destroy your engine due to redline.

 

it will only do that if there is an issue...codes that come and go do not log into the ecu

 

That's why its nice to have Cipher! As far as I know only error codes are recorded (along with a timestamp of sorts [trip count]). Full data logging is not supported by the ECU that I have ever heard of. It does not know "coolant level", just that the coolant-related DTC was triggered etc. A full list of codes are in the service manual. You can view and clear all codes with Cipher. I do not recall seeing any "rpm recording" or "over-rev" DTC in the service manual.

 

If you have no leaks . The oil had to come from some where . My guess is it was either the oil coming from the dip stick tube . Or the tranny dip stick tube . Check the under belly pan to see what side of the motor it came from and start looking from there .

 

When i brought it to the dealer, the dude was able to see in real-time exactly how fast i was going, what i was reving at, and a lot of other stuff that i had no idea what it was for. I dont know how many hours of data the ECU records, but it can definatly report over revs.

 

Wow, this is newz to me. If the ecu is using volatile memory to log stuff, then maybe resetting the ecu might wipe the log out... If it's logging to non-volatile memory like flash drives use, you're screwed... Until it logs enough data to start over-writing itself.