1966 electrical problem

[Paul L.]

I have a 1966 coupe w/L79 engine. Recently the engine has been shutting down while being driven for aparantly no reason. All it takes to start the engine again is to depress the clutch and restart the engine. I have had some issues in the past with the bulkhead connector but that usually killed all electrical power to the fuse block. i.e. nothing electrical worked. All that was needed was to jiggle the connector. I also had an issue with one electrical connection on the ignition switch which caused accessories i.e. cigarette lighteer, clock, interior lights, radio, etc. to cease operating but not the engine.
Do these symptoms indicate an engine harness replacement, a bulkhead connector replacement, a fuse block repair kit or some other repair kit?
Any help would be appreciated.

[Dennis B.]

Re: 1966 electrical problem

I have a '66 air/coupe L79 as well. Went through the same scenario as you. Check the large red wire on the engine side of the bulk head connector. It's likely your problem. I replaced the engine harness (pretty simple) and it corrected my problem. I have since replaced the dash harness (not so simple) which includes a new fuse block. So both sides of mine are fresh and no problems any longer. BTW I always felt this was very dangerous. Who wants to lose total power in traffic.

Dennis

[Paul L.]

Re: 1966 electrical problem

Thanks for the reply. Where did you purchase the wiring harness? I have found them at Zip-Corvettes, Corvette Central and Lectric-limited. They seem kinda pricey but as you said, this is a potentially dangerous situation.

[Rich G.]

Re: 1966 electrical problem

Interesting. My 66 L79 started doing this last spring. Poked around and found nothing. problem went away. It started to happen again when I was getting ready to put it up for the winter. I'll check that area too. Thanks for the tip.

Rich

[Dennis B.]

Re: 1966 electrical problem

I used Lectric Limited for both the engine and dash harness. Nice products. If you start with an engine harness be very careful releasing your connectors from the engine side of your fuse block. Very fragile. It can be done but just go slowly. Small pin connectors below those plugs.


Dennis

[Michael G.]

Re: 1966 electrical problem

Thanks for the reply. Where did you purchase the wiring harness? I have found them at Zip-Corvettes, Corvette Central and Lectric-limited. They seem kinda pricey but as you said, this is a potentially dangerous situation.

M & H Electric is another high end quality harness maker you may want to consider. http://www.wiringharness.com/. Mine was bought at Keen Parts.

[William F.]

Re: 1966 electrical problem

What "pin connectors" are you referring to-the connectors themselves inside the plugs, or the releases on the plugs that have to be pryed apart to disconnect the plug?Had this problem o nmy air '67; disconnected plug on firewall side, cleaned with electronic cleaner and old toothbrush;reconnected; problem solved.

[Dennis B.]

Re: 1966 electrical problem

What "pin connectors" are you referring to-the connectors themselves inside the plugs, or the releases on the plugs that have to be pryed apart to disconnect the plug?Had this problem o nmy air '67; disconnected plug on firewall side, cleaned with electronic cleaner and old toothbrush;reconnected; problem solved.

Referring to the actual electrical pin contacts. I found them easy to bend and also loose on mine. It made alignment of the connector from the engine harness a little touchy that's all.

Dennis

[Jim T.]

Re: 1966 electrical problem

My 1970 350/300 with turbo 400 automatic would run fine around town. On a interstate trip and the engine running fine when I would take an off-ramp it would die coming to a stop. This happened more than once. Did not know why it did this. It would start with no problems when it did this. The only thing I did later was remove the distributor and correctly shimmed the distributor gear. Do not remember how much play I removed but it did have to much. Never had any more engine dying when doing interstate trips and taking a off-ramp. Did not do anything else to the engine.

[Steven A.]

Re: 1966 electrical problem

Paul: There are numerous posts about this problem and the fix for it, but the bottom line is the current going through the firewall connector tends to melt the plastic in the connectors causing the pins to lose contact. The fix is to take off the fuse box and the hard wire this connection so you eliminate the pins for the main (12 gauge red wire) going to the ignition switch. It's actually a fairly easy job and if you do it carefully its undetectable. It will permanently solve this common problem. I did this on my '66 about five years ago and haven't had a single problem since.