Electrical/Gauge Issues- 1968 Corvette

[Gregory M.]

I recently purchased a 1968 Roadster and had it out for my first drive yesterday. Issues:

1. The tach needle bounces, especially past 3000 rpm. Any idea what causes that?

2. The water temp gauge is not working. Where do I begin trouble shooting that? The sending unit and wire look relatively new;

3. Radio does not power up though there is power at fuse panel and the fuse is good...if I check power at radio plug and its there, then I suppose the radio is bad?

4. No gauge lights at all...that little 4Amp fuse for instrument lights was bad and replaced it but still no power to either side of the fuse on the panel...how do you trace that? How does the power get to the fuse panel?

I am not sure that there is a complete set of ground straps on the car so I will check and replace them first as needed.

Also, how do those fiber optic lights work? There are 3 on each side and the outers flash when I signal...what about those two inner lights? When are they supposed to come on?

Any help would be greatly appreciated.

[Jim T.]

Re: Electrical/Gauge Issuess- 1968 Corvette

Greg can only reply to one thing right now, disconnect the tach cable at the distributor, don't loose the small washer and remove the tach gear that is in the distributor and examine it. If it is okay grease it. The tach gear can be a problem and destroy the gearing on the distributor shaft which will require a new distributor shaft and distributor gear. This lubrication is not in the owners manual but it should of been there.

[Gregory M.]

Re: Electrical/Gauge Issuess- 1968 Corvette

What is the deal with the ground strap set sold by everyone? It has only 4 braided straps and a metal band for the radio antenna. But I understand there are many more grounds...where are all of the ground straps?

[Gregory M.]

Re: Electrical/Gauge Issuess- 1968 Corvette

Where can I find drawings, ideally, of the ground strap locations?

[Michael L.]

Re: Electrical/Gauge Issuess- 1968 Corvette

Greg,

If this is obvious and redundant then my apologies ahead of time.

If you're having electrical issues, and planning on doing any other work on the car (read your intention to have the car flight judged) then you MUST get a few books for your library. the 68-69 Technical Information Guide and Judging Manual, the 68 Assembly Instruction Manual (AIM), the 68-77 Chassis Service Manual, and a good wiring diagram is essential to have. It will take some research, but by looking through these references, especially the AIM, you will be able to determine where all the ground straps are supposed to go and answer most of your other questions if someone on the forum isn't able to help you expedite the process.

As for the other items, troubleshooting many of these things are in the Chassis Service Manual and if not may be found in some of the other service manuals, like a Chilton's or similar service book. Just be patient and use a very basic step by step approach to diagnosing and fixing the problems.

Mike