[fyrffytr1]

On the last three or four times I have driven my 67 GTO, it has shut off shortly after driving maybe 200 feet.
When it shuts of the car is completely dead! No lights, horn or anything. After it sits for a minute it will crank up and run fine.
I got it home, and while idling I jiggled the ignition switch but nothing happened. I shut it off for a few minutes, cranked it back up and backed out of the garage and down the driveway. I then pulled back into he garage without incident.
What do I need to look at?

[ZeGermanHam]

Just throwing ideas out there, but do you have any circuit breakers with auto-reset in your electrical system?

[fyrffytr1]

Originally Posted by ZeGermanHam

Just throwing ideas out there, but do you have any circuit breakers with auto-reset in your electrical system?

No. The only alteration I made was to replace the points with an M&H breakerless ignition. The wiring harness was replaced with one from M&H when I built the car.

[fyrffytr1]

I just remembered that I switched to an internal voltage regulator alternator. I kept the stock engine wiring from M&H by using a junction block the goes in the firewall mounted voltage regulator housing. It also came from M&H.

[Cammer-6]

when it dies,immediately put a meter on battery
trace it to first junction and further until you find where there is no voltage.
Do not discount grounds...most ignore and later find out that was the issue.

[lucky1]

Check your positive battery lead to starter solenoid.

[OG68]

Check your firewall plugs.

[Andre]

I would look at the bulkhead connector as well as the hot line off the back of the alternator.

[george kujanski]

Total shut off indicates the main battery feed to the firewall is intermittent. The path is: from the junction at the starter main bolt to the harness that runs along the driver's valve cover where it joins with the alternator output, then thru the fusible link in the harness (this is a problem area) then thru the firewall (another problem area).

Check the fusible link, it may be corroded. It's a length of smaller gauge wire, which is intended to melt if there is a short circuit.

George

[fyrffytr1]

I haven't had a chance to try all the things that have been suggested, but I did check the connections and they all appear to be good and tight. All the wiring was replaced about 10-15 years ago with M&H harnesses. I hope to get time to look at the car this week. Funny, but when I was working it seemed like I had time to do things. Now that I am retired I can't get anything accomplished!

[fyrffytr1]

Well, I had to move the car from my house garage to my shop about 75 feet. When I cranked the car the battery was dead,. I charged it till it was
complete. Then I let it sit with the charger maintaining it overnight, This morning I removed the jumper cables and disconnected the positive cable and let the car sit for about 20 minutes. I hooked up my charger and it showed the battery was down to 85%. I am letting it sit on trickle charge overnight. I will check the charge in the morning then remove the charger cables and see if it drops with the positive cable removed.

[fyrffytr1]

It seems that the battery may not hold a charge. I charged it to 100% with the positive cable disconnected, It sat for about 8 hours before I could check it again. By then it was down to 90%. Could a bad cell be causing the problem? The only other thing I have done is replace the steering wheel and I made sure the switch was positioned correctly.Everything went back together, the horn worked and he turn signal switches worked as they should. I will check the battery charge in the morning.

[ID67goat]

Originally Posted by fyrffytr1

It seems that the battery may not hold a charge. I charged it to 100% with the positive cable disconnected, It sat for about 8 hours before I could check it again. By then it was down to 90%. Could a bad cell be causing the problem? The only other thing I have done is replace the steering wheel and I made sure the switch was positioned correctly.Everything went back together, the horn worked and he turn signal switches worked as they should. I will check the battery charge in the morning.

Yes, change the battery. I had an Optima battery that seemed like it was OK, but sometimes after driving the car it would not crank over. I thought for sure it was something with the grounds, ignition switch, etc. but after swapping the battery never had an issue again.

I don’t think that batter quality is what it used to be…..

[fyrffytr1]

Another restorer said to change the battery. I will buy a new one tomorrow. He said the Diamond brand I have has been having problems.

[fyrffytr1]

Before I go to the expense of a new battery, can someone tell me where to find the fusible link in my M&H wiring harness?

[fyrffytr1]

Could this possibly be my problem? I took the wires off and cleaned the connections, then put them back making sure they were on good.

[Greg Reid]

Phil, have you tried a trouble light or meter hooked in line with the battery to see if any current is being pulled while it's parked?

[rohrt]

How old is the battery? It may be time for a new one. I always get AC delco batteries myself.

I'm with Greg on using a meter to troubleshoot with. If you don't have a light or meter. If you touch the positive connector the battery do you get a spark (Key off, doors closed)? Do you hear any clicks of relays engaging?

Your first post makes me think its just a bad battery connection. Even if its tight it might have a bunch of corrosion. I would make sure both ends of the battery cables are good and clean to shinny metal. Do you have a separate wire off the positive battery cable that feeds the bulk head connector?

[george kujanski]

What am I looking at in the pic?

[george kujanski]

An abrupt shutoff indicates a break in the power connection to the cabin.abattery issue would not normally cause shutdown when running due to the alt providing power. The beak has to be between the bat, alt and cabin, like thru the fuseblock. Or fusible link, if the link is between the bat/ alt connection and the firewall fuse block.