Engine just shuts down

[James J.]

Took my L84 out for run yesterday afternoon, beautiful day here in NH. After about 15 miles of stop and go traffic I hit the highway and ran it pretty hard for about 5 miles. All was going great, I took an exit and after sitting at the top of the exit ramp for about 4 minutes waiting for the light to change I made it about another mile and the engine just shut off as though I was out of fuel, but it was almost full. Tried to restart but it just cranked for about 5 sec. and didn't start. I waited about 5 minutes and tried to restart and after about 7 sec. of cranking it started. I made it about a quarter mile and it shut off again. Cranked for about 7 sec. and started again. Three more times of this and I called AAA. I drove it onto the ramp truck. Got it home offloaded and drove up the driveway and into the garage. Checked the cable to the high pressure pump, all good. Jerry Bramlett went though the injection unit about five years ago and rebuilt the pump. Is it possible that the fuel pump is damaged or worn and can't keep up with the demand? The car has 44,000, I believe original miles. Not really a car guy so I need all the help I can get.
Jim Jasper

[Willard M.]

Re: Engine just shuts down

I'm betting electrical, a bad condensor. I remember the same experience in a 62 FI that I had and I was sure that it was the FI unit. Looking forward to hear what is the problem.

[Ed S.]

Re: Engine just shuts down

I agree with Willard, most likely electrical as opposed to a fuel shortage. But to confirm, you can do a simple test if and when it occurs again. You indicate that the engine will not restart immediately after it quits. The next time it quits, pull a plug wire and position it so a spark can ark to a good ground (an exhaust manifold will work fine). With the plug wire in position (don't hold it) have someone crank the engine - if you get a spark between the plug wire and the ground you can assume it is a fuel problem - no spark, then Willard was correct - you have an electrical issue. I can tell you this, the more time you spend analyzing and diagnosing the problem the less time (and money) you will spend replacing or repairing perfectly good parts. Please let us know what you find.

[Joe R.]

Re: Engine just shuts down

Take it out and drive until it stops again. Get out and have someone crank it and see if you are getting a spark at the plugs. If you are go to checking the fuel filter at the unit and then the filter in the tank.
If it ain't the ignition it's gotta be the fuel.

JR

[Bob W.]

Re: Engine just shuts down

Don't forget to check the coil and loose wires at the coil.

[Jim D.]

Re: Engine just shuts down

I had a bad coil do the same thing.

[Harry L.]

Re: Engine just shuts down

Check your gas filter

[John D.]

Re: Engine just shuts down

In the old days before Corvettes I played with Model A Fords. Started out at 11 yrs old with them. Two big issues with the 4 cylinder running was the condenser in the distributor and the ignition coil. Finally solved the condenser problem by mouting it on the firewall instead of in the distributor. Ditched the Ford coil for one from NAPA.

It's not the fuel unit James. It's perculation, fuel pump, repro coil, maybe condenser. One time this happened to me years ago on a customers '65 FI car. Member of the Pittsburgh chapter no less. Was his rusty poc gas cap. The car would run 10 minutes and shut off. Was embarrasing and really nerve wracking. So I said to the good Dr. You sure you have gas??? He said yes he thought he had enough. So I took the gas cap off and it almost hit me in the face. The pressure build up was very scary. Next I asked for a rag. Put the rag in the big hole where the cap goes and said to Dr. Roger. Let's go for a ride and the car screamed. That was about 25 years ago. Never forgot it.
Another time it was the guys ballast resistor. Recently that happened to one that I restored that went to the regional in Florida. It was his repro coil. He went in the flea market and found a buddy of his. Borrowed an original 202 coil. Put it in the 63 and the car screamed.
Another story. Recently the same thing happened in a customers '65. It was the rebuilt fuel pump.
And last of all lots of complaints because of the junk fuel. Try pure 100LL AV or racing fuel. Pure. Dont cut it with ethanol as wasting your money. Leave the distributor cover in the back seat or on the shelve. POC part. Use a hot spark plug.
Or remember what dip stick Dennis said many years ago. Take the hood off and put it in the attic. JD

[Dennis O.]

Re: Engine just shuts down

Another possibility would be a bad connection through the bulkhead connector. I had this problem with my '67 L79. There is a certain intersection about 6 miles from me that was a sharp right with a pronounced "dip" in it. Every time I went through that intersection, my engine would quit. Once I got back on the straight and flat road, it would restart easily. During this same time frame, my ammeter was not working. When I pulled the bulkhead connector apart, I could see some green corrosion in it. I replaced one failed "twin-lock" connector and cleaned the connection thoroughly, and that solved my problem. The ammeter now works, and I have been through that same intersection at least 10 times with no problem. My theory was that that intersection had just the right combination of angles and attitude change that the car would flex slightly, causing the connection problem in an already compromised junction. One further clue was that I could get the ammeter to work in the shop by twisting the bulkhead connector manually. After the clean-up, I applied dielectric gel around the perimeter of the bulkhead connectors to seal out any future moisture. It's been over two months with no problems.

[James J.]

Re: Engine just shuts down

Thanks for all of the suggested problems. I now have a place to start looking for the problem. I will get back with my findings.
Thanks again
Jim Jasper

[James J.]

Re: Engine just shuts down

Finally had some time to runs some test. Running straight 110 octane race fuel and AC45 plugs. It has gotten worse. Sitting in my driveway runs on high idle somewhere between 30 to 60 seconds, starts to stumble and then just shuts off. Removed the gas cap. No change. Put a volt meter on the primary of the ignition coil while it was running. Never lost voltage but I changed the coil to a GM Restoration 091 coil anyway, it had an original 202 in it. No change. Hooked up a timing light. Never lost spark. Disconnected the fuel line at the bowl and ran a rubber hose into a can. Pumped about a cup and a half to two cups in about 5 seconds. Ran that test twice and the car ran on what was in the fuel bowl both times. So I have fire and fuel. Still the same, when it shuts off, takes about 7 sec. of cranking to restart. I don't get it.
Jim Jasper

[Philip A.]

Re: Engine just shuts down

Do you have points or an electronic conversion? I have had TWO conversions fail and symptoms were the same. Definitely sounds electric. Check connections under distributor cap, grounds, etc

[Paul Y.]

Re: Engine just shuts down

Another possibility would be a bad connection through the bulkhead connector. I had this problem with my '67 L79. There is a certain intersection about 6 miles from me that was a sharp right with a pronounced "dip" in it. Every time I went through that intersection, my engine would quit. Once I got back on the straight and flat road, it would restart easily. During this same time frame, my ammeter was not working. When I pulled the bulkhead connector apart, I could see some green corrosion in it. I replaced one failed "twin-lock" connector and cleaned the connection thoroughly, and that solved my problem. The ammeter now works, and I have been through that same intersection at least 10 times with no problem. My theory was that that intersection had just the right combination of angles and attitude change that the car would flex slightly, causing the connection problem in an already compromised junction. One further clue was that I could get the ammeter to work in the shop by twisting the bulkhead connector manually. After the clean-up, I applied dielectric gel around the perimeter of the bulkhead connectors to seal out any future moisture. It's been over two months with no problems.

I agree about checking the fuse section in the bulk head. Next time it dies pop the hood and wiggle those two parts of the wiring harness fuse box connectors. If it starts that's your problem and the easiest to check. Let us know when you find it. I would check the FI last as it usually is electrical even back in the day when these were new. Who knew? (tongue in cheek)

[Paul Y.]

Re: Engine just shuts down

Now I'm putting my money on the cranking signal valve. That is another easy one to test. Good luck to you and keep us informed please

[Chuck G.]

Re: Engine just shuts down

Do you have points or an electronic conversion? I have had TWO conversions fail and symptoms were the same. Definitely sounds electric. Check connections under distributor cap, grounds, etc

Jerry B does often put electronic ignitions in his FI rebuilds.

I ran into one the other day on a friends 63.