TSev1

So I was at a HPDE today with the C5Z. I was in a long sweeping left hander into a braking zone. At the end of the braking zone I lose engine power. I coast for about 25-50 yards and then my dash needles reset and the engine kicks back to life. Didn't see any other problems the whole day. FWIW the oil temp was 275* and the coolant was around 220*, which seems normal.

It was actually a safety issue as I was setting up for my next turn and someone was on my rear bumper ready to accelerate. I'm glad the other guys in the group reacted the right way and didn't kill us all.

Is this like a Limp Mode thing? Is there something I can do to prevent this from happening again? Thanks for any insight.

Jnape

Pull your codes and post them.

VGLNTE1

did you run the car after? was it ok? on a big sweping turn, plus braking, you could have starved the pick up tube and lost oil pressure

TJM

[FWIW the oil temp was 275* and the coolant was around 220*, which seems normal.

It was actually a safety issue as I was setting up for my next turn and someone was on my rear bumper ready to accelerate. I'm glad the other guys in the group reacted the right way and didn't kill us all.

Is this like a Limp Mode thing? Is there something I can do to prevent this from happening again? Thanks for any insight. [/QUOTE]

Likely oil pressure that clicked you Off.

Buy an oil cooler, 275 is pretty warm.

TJM

johninar

275 was normal for me until I put in the Dewitts. Above 300 and I start getting nervous.
As was said above, codes will help.

sothpaw2

So the dash never lost power and your stuff came back to life without cranking the ignition? I had a bad ignition switch that killed everything (just like turning the key to off) but obviously it had to be-restarted to get the engine and needle indicators back on line. Make sure you don't HPDE with any keys on your key ring--FOB only.

Armycop

oil temp at 275 won't set off limp mode; 330 will though...

TSev1

alright, thanks for the input guys. I will pull codes later today and post. It was a fast left sweeper and at the end when trailbraking, it pulls a lot of g force. Oil pressure sounds like it could be the culprit. The car ran fine the rest of the weekend but we were in the rain so it wasn't nearly as fast or hot.

For the first time on track in a Z, it was a great experience. Loads of power and it did outstanding in the rain. I really embarrassed a lot of Porsches and Supras.

JimbeauZ06

Fuel level? If you were less than quarter tank in a sweeper you could have lost fuel. This is my usual reminder that its time to add.

Zip Corvettes

Has the car been tuned? What about aftermarket or modified MAF?

TSev1

car is stock. Just a catback and oil catch can, street tires. Fuel level was around a half tank. I've had fuel starvation before and this wasn't the case.

I didn't have to crank the car to get going again. The engine didn't completely die. Just my inputs weren't doing anything and the gauges went dead. No throttle, no clock, no climate control, no gauges. I rolled to a safe zone off the driving line, and then bam, everything went back to life. I'll pull the codes and we'll have more info later today. Thanks for the thoughts thusfar.

waddisme

Doesn't sound like "Reduced Enging Power" as the code has to be reset for that to turn itself off. 275* and 220* sounds pretty normal for stock Z. Did you put the extra quart of oil like the manual recommends for track days? Hopefully not an electrical issue - they can take a long time to trace down. Curious what codes you have.

TSev1

yeah i had an extra qt of oil in there. Sorry I didn't get the codes last night. Worked 12 hour day. I'll try later today.

Zip Corvettes

So you lost "electrical power"

AU N EGL

Was the car slightly sliding though the sweeper just before it went into limp mode?

if so TC took over, and the electrical gremlin may have been the computer was overloaded with data so it reset itself. Seen this a few times.

TSev1

Actually, that sounds exactly like what happened. I trust your knowledge of vettes at the track so if you've seen this before, I won't worry too much. I was in Competition Mode, I guess I just need to turn it all off. Thanks for the help. I'm not too worried anymore.

JiminVirginia

Are you sure it wasn't a case of "ice mode" triggered by applying the brakes when the yaw sensors are telling the engine computer that the car is too unbalanced to use the brakes? I've had this happen on my C5. You lose brakes and just about everything for a brief second or so until the elecronics detect that balance is restored.

Bill Dearborn

That sounds like a plausible scenario but I don't think it is one. The car is a system of subsystems. Each one does its own thing and then communicates with the others as needed. The EBCM handles all of the active handling and TC issues and only sends a message to the PCM to reduce torque. I know the EBCM can't directly affect the gauges and I seriously doubt the PCM would get overloaded with data like a personal computer would. The PCM has a narrow range of data (finite unlike a PC which has an infinite range) to work with and an automaker can probably test 100% of situations encountered to make sure it works properly before releasing it to the public. Since he was in competition mode the EBCM didn't even send a TC message to the PCM so there was no data except what the PCM itself was working with.

Bill

TSev1

You guys know way too much about these cars!! Lol. I'm going to double check all of my connections and go over simple stuff. I'm not too worried about it unless it happens again. I won't know until next season but I will run with Traction completely off to prevent anything from happening. Thanks for the help everyone!! You are all awesome!!

TSev1

Hmm, Ice mode. I'll have to look into that because I was trailbraking at the time.