Electrical issues

[Billy Mild]

I just recently bought a C4 ZR1. I bought it almost site unseen. I was told everything worked, car didn't leak any fluids, and it was a good runner.

The issues with the car were it needed tires, and some minor interior work.

Well so far it has been alright. I did change the oil, trans fluid, and rear end fluid. In an attempt to get the radio working I unhooked the negative battery cable for a few hours in hopes of clearing a code. That didn't work, but on my drive to work the other day I noticed something. The car would almost stall out for a split second. The lights would get a little dim, AC would stop running for a split second, then continue on no problem. It would be so fast I couldn't even get it on video.

The LTPWS light was very dimmly lit as well. Then the Service ABS light came on half way through the drive. The next drive the Service ABS light did not come on.

Could this just be bad grounds or something more serious?

[WARP TEN]

it is fairly common for ZR-1s to have corroded ground connection issues, especially the connections at the back of the engine. Also an old and weak battery may cause this sort of gremlin. Search the forum and you will find a lot of info on the subject of ground problems and electrical gremlins. -Bob

[Billy Mild]

I cleaned the main ground points in the interior. 2 up front by the speaker pods and then 2 back around the loop by the rear hatch.

I haven't driven the car yet, but are there any other grounds that I could get to without taking the intake manifold off?

[mike100]

Sometimes the aftermarket chips program both fans to come on at the same time. This does cause my gauges to dim so I reprogrammed them to come on 1 degree (celcius) apart.

Also, C4's get wonky right before you lose a battery.

[USAZR1]

Also, C4's get wonky right before you lose a battery.

Yep. Been there,done that.

[Billy Mild]

Yep. Been there,done that.

Should I have the battery tested? It is an interstate battery.

I left the car on the battery tender all last night. It fired right up today and seemed to run fine, but I still noticed some of the LCD screen dimming. Also I had the car alarm going off after I got inside the office today. That was exciting.

I'm trying to get a video of it when this happens. The idle doesn't change, but the volt meter goes up and down a little bit when the turn signal is on. That points to some sort of electrical issue. I would like to have all my grounds clean and tight. Maybe it is the battery.

[USAZR1]

Should I have the battery tested? It is an interstate battery.

I left the car on the battery tender all last night. It fired right up today and seemed to run fine, but I still noticed some of the LCD screen dimming. Also I had the car alarm going off after I got inside the office today. That was exciting.

I'm trying to get a video of it when this happens. The idle doesn't change, but the volt meter goes up and down a little bit when the turn signal is on. That points to some sort of electrical issue. I would like to have all my grounds clean and tight. Maybe it is the battery.


I would have the battery load-tested before you start chasing bad grounds. Your symptoms do sound like the battery is going south.

[ghlkal]

I agree that you should check your battery first.

I haven't driven the car yet, but are there any other grounds that I could get to without taking the intake manifold off?

Most of us have discovered that the two grounding points on the back of block near the bellhousing are critical. Cleaning up those grounds seems important. Unfortunately, I'm not sure if you can get to them with the plenum in place. I cleaned mine up when I had the plenum off.

[Billy Mild]

ZR1 idling gauges dim: http://youtu.be/aabq_eOLpd4

There is a video of what is going on. My ABS light hasn't come since I cleaned all the interior grounds. So at least there is a little difference.

I can get my battery tested tomorrow.

[mike100]

thanks for the video...that wasn't exactly what I was expecting. I would say a gauge cluster ground or voltage regulator issue is the problem.

[Billy Mild]

thanks for the video...that wasn't exactly what I was expecting. I would say a gauge cluster ground or voltage regulator issue is the problem.

I have cleaned the 4 main grounding points inside the ZR1. I haven't had the ABS light come back on since doing this, but that dimming gauge thing still was happening. I will be cleaning the grounds when I pull the plenum in the upcoming weeks.

[Paul Workman]

Pulling the plenum is a "right of passage" for ZR-1 owners!

It is incredible the amount of gremlins you can kill by R&R'ing those ground lugs at the back of the motor! Be sure too, to use some contact cleaner and a wire brush and get the lugs bright. then coat them with dielectric grease before replacing them on their posts. Be sure to clean the block where contact is made with the ground lugs as well.

You might want to inspect the solenoid contacts on your starter while you have the plenum off - an excellent time to replace the posts and clean up the contact ring, as long as you're under there!

Using a thin putty knife you may be able to slide it between the plenum and the gasket and keep the gasket intact. But, if not, Jerry's Gaskets (http://jerrysgaskets.com/store2/root/) has the ones you want.

As others have mentioned, low voltage can cause a host of problems. Low voltage can be a bad battery, as mentioned, or corrosion of one or more of the battery terminals, or the alternator not charging properly. All of these can be checked at a Walmart car care center: they can load test the battery clean the terminals as needed, and also load test the alternator.

couple all of these together, and I'd think you'd pretty well R&R'ed maybe 95% of the electrical stuff that will ever cause you issues.