Runs Fine And Now Won't Start - What Did I Do???

[Bill B.]

Re: Runs Fine And Now Won't Start - What Did I Do???

Don, How did you make out with the issue?

[Don L.]

Re: Runs Fine And Now Won't Start - What Did I Do???

Don, How did you make out with the issue?

Thanks, Bill. I’ve actually put this project on “pause” for a couple weeks. I’m in Michigan for vacation. Timed the trip to align with Woodward Dream Cruise and Corvettes at Carlisle. I’ve gotten some good advice from folks like you and plan to jump back into it when I get back to North Carolina on Sept 1. I’ll post an update once I get back into it.

Thanks again.

[Tom L.]

Re: Runs Fine And Now Won't Start - What Did I Do???

Hey Don, was hoping you'd be taking a practice run in your car for next year, you know that '72 and 2022 thing. Weather permitting I'll have mine there next week and next year too. Good luck getting your issue sorted out. Enjoy!!

[Don L.]

Re: Runs Fine And Now Won't Start - What Did I Do???

Good morning all.

I’m sorry to report that after 6 weeks and numerous attacks at my nagging elec problem, I’m still struggling. So far, I’ve rebuilt the starter and solenoid. I’ve replaced the battery switch and the ground cable from starter mount to frame. I’ve cleaned all terminals (they all looked good before cleaning). I’ve tried a couple different batteries. After doing all this, the car would start, however, not seeing any real changes in what I did, I wasn’t comfortable that I had found a root cause, so to me, the car was not dependable enough to venture out.

Some new info I’ve gleaned over the past couple weeks include the following:
- When I get the “click” instead of “crank”, I see a 9 volt drop when the key is turned to start. When it cranks, I see a 3 volt drop.
- When it “clicks”, all power goes out until I disconnect/reconnect the battery.
- I’ve now noticed that when I reconnect the battery, I can get all power to go out by stepping on brake pedal (weird).
- While at Carlisle, I stopped in at the Lectric Limited spot and bought a new battery switch and ground cable. I described my problem to the LL Tech. He told me my problem is definitely in the battery circuit.


I worked on it this weekend. The car started just fine, numerous times. It started and ran well, so I took it out for a run but waited till I got home and put it on the lift before shutting it off. Good thing I did. It failed when I shut it down and went to re-start.

I suppose I now suspect fusible link(s). Does it make sense that a weak/bad link could fail when the car reaches operating temperature? I ask this because when I experienced the first failure in early August, it was after it reached temp while checking accuracy of new temp sender and adjusting idle speed.

Thanks for reading this long and now very frustrating update. Any feedback/advice is much appreciated.

[Bill B.]

Re: Runs Fine And Now Won't Start - What Did I Do???

Hi Don,

Unfortunately I'm leaving NC tomorrow morn back to CT for a bit, otherwise I'd drive over and help.

Yes, definately, when the vehicle warms up, something is changing.

On the brake pedal relationship ... the common related component is the Clutch Safety Switch. It is located on the brake/clutch pedal assembly. Depressing the brake pedal is probably slightly moving the switch ever so slightly. I'd try temporarily by-passing that clutch switch (it has a couple of connectors in series with the harness near that switch and on the switch).

Secondarily, the fusible links near that horn relay may be related, but to me, that brake pedal phemonana you described pretty much zeros in at that switch.

Next time when hot, you could also try holding the key in the start position while depressing and releasing the clutch pedal several times (just make sure you have the vehicle in neutral when you try it, just in case it starts mid way during a clutch depression)

[Don L.]

Re: Runs Fine And Now Won't Start - What Did I Do???

Hi Don,

Unfortunately I'm leaving NC tomorrow morn back to CT for a bit, otherwise I'd drive over and help.

Yes, definately, when the vehicle warms up, something is changing.

On the brake pedal relationship ... the common related component is the Clutch Safety Switch. It is located on the brake/clutch pedal assembly. Depressing the brake pedal is probably slightly moving the switch ever so slightly. I'd try temporarily by-passing that clutch switch (it has a couple of connectors in series with the harness near that switch and on the switch).

Secondarily, the fusible links near that horn relay may be related, but to me, that brake pedal phemonana you described pretty much zeros in at that switch.

Next time when hot, you could also try holding the key in the start position while depressing and releasing the clutch pedal several times (just make sure you have the vehicle in neutral when you try it, just in case it starts mid way during a clutch depression)

Thanks Bill. I sent you a PM, hoping to speak live on this issue. I'm not sure I fully understand your suggestion from this morning.

Thanks

[James G.]

Re: Runs Fine And Now Won't Start - What Did I Do???

I second the fusible links as a source of the issues.

To bypass the clutch switch - take a 5-6" piece of 10 or 12 gauge wire and crimp a male spade on either end then insert it into either side of the clutch safety switch harness plug -

[Don L.]

Re: Runs Fine And Now Won't Start - What Did I Do???

I second the fusible links as a source of the issues.

To bypass the clutch switch - take a 5-6" piece of 10 or 12 gauge wire and crimp a male spade on either end then insert it into either side of the clutch safety switch harness plug -

[James G.]

Re: Runs Fine And Now Won't Start - What Did I Do???

Correct 2 purple wires.