1964 Convertible, 327-300, manual trans.
I posted previously regarding this issue and thought it was resolved.
https://www.corvetteforum.com/forums...-when-hot.html

After driving the car for anywhere from 3 to 7 minutes, the engines stalls. The car will not restart. If I wait about 10 minutes, it starts right up and drives again. (at this point I will only drive it back to my garage).
I was first told that the coil may be over-heating and since it was old I changes both the coil and the resistor ballast. The problem has returned.
The car also has a "no points" module, and a new Edelbrock 600CFM model 1406.
The car was rebuilt 3 years ago, a ground up, body off resto done by me. All parts are new except the rebuilt original drive train. The problem began in September of 2020 before I garaged it for winter and returned today.
My question is, what can the issue be? I realize it could be many different issues, (electrical, fuel related, etc.) But I don't want to just throw money at it replacing one part at a time until fixed.
If any mechanically inclined members can offer an idea, I'd very much appreciate it. The car is no fun if I can't drive it.

Thanks in advance for your help.

 

I would take a look at the flexible hose which connects the fuel pump to the frame mounted fuel line. These have been known to collapse from pump vacuum. When that happens, engine will run for a couple of minutes on just the fuel in the carburetor bowl.

If you determine the hose is collapsing, buy a small length of coil spring at the hardware store and insert it in the hose.

 

The first thing I would do is when it won't start see if you have spark or not, If it does you can eliminate half of the troubleshooting. Alternatively, you could check to see if it's getting fuel. into the carburetor when it won't start and eliminate the other half first

 

Does it just shut off, as if a switch was flip, or does it stumble/stutter to no run? Dennis

 

I would guess it is flooding out. If it does it again put your foot to the floor and hold it there and crank. Dirt could get under the needle and seat.

 

Thanks for all the suggestions so far.

65 GG vert: Can't say about the spark since I didn't have a tool to check it either time, but I'll leave it in the glove box for the future. As for the fuel, I checked and it WAS getting fuel to the carb.

Bluestripe 67: The first time it stuttered prior to shutting down. The second time (today), it just shut down while driving (approx 40 MPH when I realized the motor had shut off).

65 Pro Vette : Didn't seem like it was flooding. No gas smell when I stopped and I tried to restart as you suggested but it wouldn't start until some time passed (usually about 10 minutes)
Not sure how dirt could get in the needle and seat. I'm the only one who drives and gasses the car and the tank was cleaned during the resto but I did consider that. I only put about 1500 miles on it in the last 3 years since the resto.

 

When it does this and you say it won't start, does it crank the engine over or just dead?

 

Where is Frankie?? Doesn't he always say shake the bulkhead connector?? If it has fuel then it cannot have spark and not start. Intermittent means it is happening under vibration??? You have changed the coil and resistor and have fuel, so shake some wires.

 

Tell us more about this "no points" module.

 

Coil or bad contact from coil wire to cap

 

When this has happened to me it was the main 12V feed through the inside most bulkhead connector. When this happens there are no interior lights, radio or power to the engine. It will not turn over at all. If you move (wiggle) that bulkhead connector on the engine side of the firewall it should temporarily provide power. The contacts need to be wire brushed and cleaned for the more permanent fix. I hope this helps with your search for the the reason our engine stalls.

Steve Stone (original owner, '63 triple black convertible, 596,000 miles)

 

He drives 5 to 7 minutes and it dies. He waits about 10 minutes and it starts.

Seat of the pants I think it's heat related and electrical. Possibly the new coil is bad? Not likely but it happens. Might toss a IR heat gun in the glove box and next time it dies take some temps for later comparison.

When you ARE finally able to re-start - do you have to crank it a bit, like bringing in more fuel, or does it fire up immediately as if nothing was wrong?

 

Thanks for all the thought. Here are the responses to them.

65 GG Vert ; It cranks but won't start.

R 66 ; bulkhead connector is tight and brand new when restored.

Kells dad ; it's a small electronic module that replaces the points. Not a H E ignition.

GDC1962 ; as stated, the coil was just replaced, as was the ballast resistor. Coil wire was the first thing I checked. Not the problem .

Steve Stone ; While driving yesterday at about 40 MPH, the car stalled while moving. All accessories remained working. I didn't even realize the car stalled until I stepped on the gas and it didn't accelerate.

Railroadman ; I thought it was heat related when I changed the coil. Yesterday, the temp was 45 degrees and when the car stalled it wasn't even 120 degrees on the gauge as it was only running a short time before stalling. (running a 180 degree thermostat). After waiting it starts right up. no waiting for fuel to reach the carb.

 

12 posts and none casting serious doubt upon the one thing that can, will and has plagued many. Why would anyone first check for a fuel problem based on the description?

Mike, remove the points substitute you have in your distributor and replace them with a set of properly gapped points and see if your problem remains. I wouldn't look for an iota of trouble anywhere else until you do yourself that simple favor. Fuel starvation does not present as an engine quitting so abruptly that you don't notice. If the trouble remains I would look next at the bulkhead connector, a known trouble source. A new bulkhead connector is not an assurance there will be no future problems in this area.

Dan

 

I would look at the "no points" module/system. Do you have a point/condenser distributor you could swap to see if that is the issue. It seems like a lot of people have trouble with the breakerless system on this forum. When it dies, however, I would check for spark. Simply remove the high tension cable from the coil, crank the engine, and touch the cable to something other than fiberglass to check for spark.

 

The bulkhead connector issue is not consistent with your symptoms. When it is bad, you lose all power except the horn. It won't try to crank.
The two most likely issues are the module you have or a wiring issue.
It sounds like you have an SE breakerless system. If so, it will have 8 metal vanes that rotate and pass the module mounted in place of the points and condensor to create the ground to cause the spark. You can convert back to points and condensor in a very short period of time for troubleshooting and that is much cheaper than buying another module (probably $250 range)
I have an SE module in my 60 and it is very solid and reliable, but things can happen. I once had the EXACT symptoms you describe. It happened twice about a month apart as I was going to a cruise in. (same destination, I thought maybe it was fated that I not attend). My cause turned out to be the small black wire that connects to the negative terminal on the coil and goes up through the bottom of the distributor to the side of the module. (stock, was connected to the points). After being stranded twice and eventually it started and I drove back home, I was going to change back to points and as I took hold of the small black wire, it pulled out of the terminal on the coil connection. The wire end was not in good shape and it pulled right out. I cut about 1/8" off the end and recrimped it back into the terminal and reconnected to coil. That was two years ago and it hasn't even sputtered since.
The first time it died, I had no spark, so I pulled the distributor cap to look and when I put it back it ran good for a month. Second time same scenario. Got to my garage and pulled cap to put in points, and that is when the wire pulled out. Only a few strands were inside the terminal end. Check the end going to the coil and the end connected to the module for good connection to the terminal AND terminal to screws.
That is why I asked you early on to check spark. You have to know what is failing before you can reliably fix it.

 

This is what a Breakerless SE ignition looks like with the distributor cap off:

 

So I just came in from letting the car idle in the driveway for 45 minutes without any issues.
While running I tried to move the bulkhead connectors, the connector for the "points eliminator" from Accel (model 2010ACC)

and the wires connected to the coil. No issues there.
I'm not ruling out the points eliminator (it may be bad but I'm not sure yet) but the wiring seems fine to me.
I'll be checking the fuel line at the tank for collapsing as suggested but it's looking like some vibration may be a factor in the stalling.

Happy for any other suggestions as I move forward. My last resort is to take it to a Corvette guy I know and have dealt with before. He knows his stuff and hopefully he'll find a fix.
Thanks to everyone who commented.

 

It's easy enough to check for spark when you get to a crank/no start interval. Don't even need to pull the module in the distributor. No need to make this any more complicated than necessary.

I have one of those photo-optic modules, so old its a Mallory, no Accel. They do go bad from time to time, usually because of another fault in the wiring, coil, or a half-fried alternator.

 

Please stay with me, this is a long thread. First let me say thanks to all of those who commented on this problem. If you’ll try once more to help it would be greatly appreciated.

I read through all these comments as well as some other posts regarding similar issues. I now have a much better understanding of how to trouble shoot the electrical system on the C2.

I’ve spent countless hours under the hood going over every wire and I now believe I found something of interest. I’d like someone to tell me if this is the issue I’m having.

To answer your previous questions more clearly I’ll recap.

• When the car stalls, the engine will turn over but not start. The last time it stalled (yesterday in the driveway) I put a test light on the #1 plug and when I turned over the engine, the light only sparked one time. The engine continues to turn but doesn’t start or spark again. NOTE: I have a video of the test light but I'm not able to attach it for some reason.

• I also tested the points eliminator in the dizzy based on something I read online and it seems to be working fine.

• I do not believe this is a fuel issue. Carb always emits gas whether running of stalled. I also removed and tested continuity on the ignition switch while jiggling the key and tapping it to see if it reacts to vibration. It did not.

• With the key on and all wires connected, I got 6.21v on the POSITIVE side of the coil & 1.17v on the NEGATIVE.

• With all coil wires disconnected to test the coil, I got 1.9Ω between the POSITIVE & NEGATIVE posts. I got 9.58Ω between the POSITIVE post and the tower (where coil to dizzy connects). So I believe the new coil is good.

• When the car stalls I get 6.34v on the POSITIVE and 1.14v on the NEGATIVE coil posts.

So after going over all these things I went to the bulkhead harnesses that some suggested. Every time I checked or wiggled these there was no effect whether running or stalled. Given their location it’s hard to see the female side on the firewall. I took a couple pics and found something of concern. In the firewall picture, you can see that one of the prongs on the harness is somewhat pushed in. (upper right hand corner) I took a needle nose and pulled it out but it seems to not stay when the male harness is reconnected. I’m thinking I may have to remove the fuse block to repair it if possible. On the second pic I circled the corresponding wire (it looks black to me). I assume it’s a ground but I’m not sure. The harness is from LECTRIC LIMITED and I attached a pic of the schematic. I also have the ’63-’65 Corvette Wiring Diagram and have attached a picture.

So this is the only thing I found so far that I believe might be the issue. I’m having difficulty understanding the diagrams since they are wrapped in the Lectric Limited diagram and in the other it shows only 6 wires in the schematic and the harness clearly has 8 pins and 8 wires.

Does anyone know what this black wire is and might this be the problem of the car stalling intermittently?