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Engine Dying Randomly

6

67TXStang

Member
I finished rebuilding my transmission and went for a drive today. As I backed out of the driveway, the car died. I started it back up, thought it was a little odd, and then drove around for about 10 minutes and came back home.

I left a short time ago and again it died backing out of the driveway. It took several attempts for it to start. The starter was turning but it would not start. After about six attempts, the car started. I made it about 30 yards and it died again.

I decided something was wrong and tried to circle the block. It died three more times trying to make it around the block. It would die when idling and also at 2,000RPM.

What do you think is the cause? Ignition switch?
 
Before you start replacing things, when it dies, see if the car is missing fuel, spark or air. You may just have a loose or pinched wire. I just had a hot wire to my coil come loose. Car would miss and die but ran at low speeds. Rev it and it would die. Found the hot wire to the coil loose but not off. Snugged it down and cost me nothing. Look and test before you spend.....
 
Did you reconnect the vacuumhose attached on the intake manifold and runs backwards to the rear of the transmission?I believe your car is running lean because it sucks air through the small opening or small hose that is attached to the trans modulator.
 
I have a 3 speed toploader. It does not have the vacuum connection.

I drove it around this morning for about 15 minutes with no trouble. I then parked the car for a while and decided to drive to the store. I made it about 40 yards and it died. It started back up immediately and I just went back home.

It continues to happen when I don't have time to check things. In the mornings when I have time, it does not happen.

It has new plugs, wires, coil, cap, rotor, carburetor, fuel filter... Those don't really eliminate any of those systems as the cause but lessens the odds.

Seems like this is going to be a pain to determine. It normally starts after a few tries when it dies. I guess I'll just start it in the garage and hope it dies so I can check a few things.
 
When it dies and is hard to start, do you have to pump the gas pedal? Does it finally start with a puff of black smoke? Any backfire at all?
 
I just returned from the garage.

I started the car and let it idle. It died after about 3 minutes. The fuel filter is see through and it is as full as always. Although I don't believe it is the best way to test if you have fuel, I moved the throttle linkage and fuel came out of the accelerator pump.

I tried to start the car without pressing the gas. It started immediately without any smoke. It ran for a couple of minutes and and then died. It dies so smoothly it is like someone just turned off the key. I started it back up on the first attempt again without using the gas pedal and without any smoke.

Any advice on testing the cause? Since it is starting the first time I try to restart it, there is no time to really troubleshoot anything.
 
When it dies, instead of turning the key off, leave it in run, grab a meter and see if you still have power at the coil. If you have gas and it starts that easy, it must be an elec. breakdown.
 
"AzPete" said:
When it dies, instead of turning the key off, leave it in run, grab a meter and see if you still have power at the coil. If you have gas and it starts that easy, it must be an elec. breakdown.
Click to expand...

I agree...maybe the coil is crapping out when it gets even a little bit warm?
 
I would say that should be ok. That should eliminate the ign. switch as a problem also. I would be tempted to find another coil and swap that in. What about your dist. What are you running, points or electronic?
 
I still have the original coil I took off. I installed a Petronix coil about 200 miles ago. It still looks brand new. I could swap back to the old one to see if it makes a difference.

The distributor is the original distributor with a Petronix 1 installed.

I just let it run for 15 minutes in the garage and it did not die. Strange how 30 minutes it died 3 times within 10 minutes.
 
My coil went bad and I was able to diagnose it. It would run and had spark but it was weak. I found this advise on the web. It was useful in finding if my coil was bad.
Using an ohmmeter, check the resistance between the side terminals of the coil. Do this with all of the wires to the coil disconnected. You should see 0.75 to 0.81 ohm of resistance. Then check the resistance between either side terminal and the center high tension terminal. The reading should be 10,000 to 11,000 ohms. Any significant deviation from these numbers would indicate that the coil is defective.
ignition_coil2.gif

Mine didn't die but became really hard to start. Some coils will fail when hot.
Good luck
 
I would go back to points and a stock coil. You may have a Pertronics problem and the fastest way to find out is swap in the old.....
 
I checked the new petronix coil and the stock one. They both have about 1.8-2.0 ohms resistance between the two connection points. The new one has 11,400 ohm between the center and either connection. The stock has 9,000 ohm between the center and either connection.

My understanding was the resistance between the two connection points should be near 1.5 ohms.

I can switch to the stock coil tomorrow and see how long it will run. I can switch to point because I don't have any. The car came with the Petronix. I don't really know how to setup points but I could figure it out if the coil does not reveal anything.
 
That coil swap should tell you what is up there.

If it is the Pertronix I system, you will need a rotor, points and condenser. You will also need to get one more screw to hold things down unless the PO left them there. They are real short, large headed screws, special for that use. Shop man. will explain the install. I ran several pertronix units in the past and always carried a set of points just in case......
 
Well, I still don't know the cause.

I ran the car the car for 15 minutes twice last Sunday. It died three times during the first 15 minutes. This allowed me to test a few things. I waited about an hour and it ran for 15 minutes without dying.

I swapped the coil out on Monday. It ran 15 minutes without dying. It did the same on Tuesday and again today. I drove it around this afternoon (only 5 miles) but it did not die.

I thought I would put the old coil in just to check. I did and ran the car twice for 15 minutes and it did not die. I'll keep messing with it but wanted to post and update.
 
I was never able to find the cause for this problem because it stopped happening. As it became colder, I stopped driving and worked on my rear axle. I drove around today for the first time in about 1.5 months without trouble for 11 miles. I tried to start the car a few moments ago. It started and ran for a few minutes and then died. I was not able to restart it.

I checked the see through fuel filter and it is full of fuel. If I move the throttle linkage, the gas comes out the accelerator pump nozzle. So I don't think the problem is gas.

I have a little tool which goes in place of a spark plug and clips to a ground. You can adjust the gap and it should spark like a spark plug would if everything is fine. I tried this next and it would not spark.

I could not remember how to check the coil and this type thing came and went so quickly, I just swapped the coil with my spare from the trunk. This took about a minute and still no spark using my little testing tool.

Before I could do anything else, the problem disappeared and I could start the car. Is the only thing left to check the petronix?
 
I would get a set of points and condenser and try that. If the Pertronix is bad, the points will work good.
 
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