Screamin Z

Looking for some insight.

On track the next few days at Mid-O and experiencing electrical issues. After 20 min or so into a run the car will completely cut all electrical power to the car. Motor, instrument panel, everything.. Poof.

This only occurs in high RPM situations.. Above 6000 RPM's. push the button to simulate turning the car off.. Clutch it and it will fire right back up.. And with NO CODES! A scan with my tech 2 shows nothing..

I've checked all the major grounds and power connections.. Anyone else experience an issue like this?

06 Zo6

VetteDrmr

With no codes sounds like the PCM is losing power. I'd start checking for loose connections, high torque and vibration somehow combining to cause your problem.

Not much help, but maybe something will free up.

HTH, and have a good one,
Mike

dvandentop

damn sorry to hear you guys are still battling that **** thought it was good? did it act up last weekend at hallet?

Screamin Z

No it ran fine at hallett.

dvandentop

WTF damn car, any changes since then or just reg maint to the car??

crease-guard

That's weird not throwing any codes, unless the PCM just get's completely wiped when the power cuts so it doesn't save any.

I was throwing a code, 1637 I think, at high rpms and high speeds. Code was L-terminal voltage failure or something to the effect. It's a feedback sensing circuit to the PCM. Occurs with alternator failure or with failure in the main lead that goes from the alternator back to the solenoid. Turns out that lead has a couple of fusable links in it and this lead is prone to failure after some time. Also read you can have corroded or loose connections of this feed at the solenoid as well. Not an expert, but I suspect something in that area. If the PCM were bad, it probably wouldn't fire right back up and fine otherwise with no codes.

Jay

Screamin Z

After going to a backup alternator and battery with no fix, the car is on jack stands cooling off before I start looking at connections.

Screamin Z

FYI.. All connections are tight.. Grounds and power connections.

crease-guard

Check the voltage between the alternator terminal and to where that link connects to the solenoid while the car is running. See if there is a voltage drop across that connection. It should read 0v.

If it's not the alternator itself and this only happens over 6000 rpm, one would think it has to do with either a signal or voltage coming from the alternator. Having swapped out both the battery and the alternator, you've effectively eliminated those two things.

If that's doesn't work, send a PM to Bill Curlee, he's the electrical guru here on the forum.

Also, I think I remember reading something to the effect of a protective circuit somewhere that senses the current and/or voltage from the alternator and if it gets too high, will cut the juice to the pcm. Don't quote me on that, I may have just imagined it.

crease-guard

How about the ignition and spark system? Maybe it's not a voltage alternator problem at all Perhaps when the vehicle is hot AND at high RPM there is something shorting that is actually shutting the car off.

Wasn't there an issue with the ignition switch on some of these cars? Let me do a search. I'm perplexed by this and need to find an answer.

Screamin Z

It is ignition related. When the car dies it is still sending fuel to the cylinders. If you keep your foot in it it will backfire like crazy. But if you lift it will stop.

sothpaw2

Yes I experienced those syptoms on track. Exactly those...but my car is a 2002 Z so a very different car. Mine also seemed to be more caused by left turns.

Nevertheless, the complete loss of power (even the Hud went out) indicated an ignition switch issue because of the way that the Hud is wired. Replacing the ignition switch (right where the key goes in) fixed this. The cause was that I had other keys (house, etc) on the ring even when I used it on track...that was too much weight for the switch internals and it wore out very prematurely.

I now track w/only the ignition key, no others hanging from the ring (in fact,no ring at all).

So...this all comes down to wiring diagrams. Check and see how your HUD is wired and ensure on track that the HUD is indeed losing power. Again, this is what narrowed the search for me...the C5 Hud is pretty much coming right off the switch.

Screamin Z

Here is a clip.



Trying to check the connections at the BCM and ECM