What the HECK is going on

[mbrew2]

Just when I thought I had all of the gremlins sorted out on my car a new issue jumps up! For the past month or so, out of nowhere, it just shuts off driving down the road. No sputtering, hesitation or any warning. Just shuts off like you turned the switch off! When it happens I can put in neutral and it immediate restarts and runs normally. In my mind, I'm trying to equate this somehow to the electric choke. It has only happened when the engine is cold and has been driven less than a mile or mile and half from my house. Absolutely no problem after I restart it. I have noticed that the choke is not operating the same as it used to. Sometimes works going to fast idle on cold start and sometimes not requiring me to moderate the throttle to keep it running when I first start it after sitting overnight. What I can't figure out is how the choke, if that is the problem, could cause a loss of power to the engine. Last time it happened I was in heavy traffic turning into a fast food joint with a full cup of hot coffee in a regular cup in my right hand and suddenly no power steering or brakes. Made for a few exciting seconds. Has never happened after it warms up. Any suggestions would be greatly appreciated.

 

[detritusmaximus]

i had a similar issue years ago with my 70. Turned out to be a loose terminal on a coil wire. It acted exactly like a switch...basically it was.

 

[batwrangler]

And could be a bad ground on the coil too had it happen on my old Lincoln

 

[stanger73]

If you are running a Durasprark or MSD distributor, check the magnetic pickup on the distributor. I had an intermittent issue with my 73 that I could not figure out. The car would run fine, and then shut off randomly while driving. When testing the resistance on the magnetic pickup while the engine was cold, it tested fine. When it got hot, the pickup would fault, and the circuit would open. Replaced the magnetic pickup, and problem solved.

 

[Don C]

With the engine idling, move wires and wire harnesses, under the hood, a little and see if you can cause it to stall. Do you still have the ported vacuum switch connected and operational? If so it could be vacuum related, and when the engine warms up enough you get vacuum applied to the vacuum advance. Make sure everything inside of the distributor is working and nothing is loose, like the breaker plate ground strap and condenser, and the points or electronic ignition pickup are adjusted.

Also, while it is idling, try moving the ignition key back and forth a little, see if that causes it.

 

[mbrew2]

Just when I thought I had all of the gremlins sorted out on my car a new issue jumps up! For the past month or so, out of nowhere, it just shuts off driving down the road. No sputtering, hesitation or any warning. Just shuts off like you turned the switch off! When it happens I can put in neutral and it immediate restarts and runs normally. In my mind, I'm trying to equate this somehow to the electric choke. It has only happened when the engine is cold and has been driven less than a mile or mile and half from my house. Absolutely no problem after I restart it. I have noticed that the choke is not operating the same as it used to. Sometimes works going to fast idle on cold start and sometimes not requiring me to moderate the throttle to keep it running when I first start it after sitting overnight. What I can't figure out is how the choke, if that is the problem, could cause a loss of power to the engine. Last time it happened I was in heavy traffic turning into a fast food joint with a full cup of hot coffee in a regular cup in my right hand and suddenly no power steering or brakes. Made for a few exciting seconds. Has never happened after it warms up. Any suggestions would be greatly appreciated.

UPDATE: Shortly after posting this my problem magically disappeared - until now.  The issue stopped after I was leaving my house with the engine cold and choke partially on. As I hit the street, I floored it. Motor bogged down a little, Backfired thru the carb, and picked right up. Has not shut off since until about a week ago and now having same problem.  Just shuts off going down the road. I can put it neutral, crank it, and it immediately re-starts and runs normally. I have checked all electrical connections to choke, coil, and distributor and can't find any loose connections. Thought maybe a fuel issue or trash in the new carb but can't make sense out of that since it immediately restarts with no hesitation. It has a mallory unilte distributor which I know nothing about. I currently have the primary fuel bowl set a little below the line per Summit recommendation. Only happens when it is cold. Other than checking all connections - I'm at a loss as to how to troubleshoot the issue since its an intermittent problem. Some days it will shut off twice before I get a mile from the house and sometimes not at all. Anywhere else I can look for the cause.

 

[Don C]

I'm leaning towards an ignition switch or problem between the ignition switch and the coil. I would run a temporary wire from the + side of the coil to a point where I could connect and view a voltmeter and see if it goes to zero when the car dies.

 

[clevelandcoupe]

MB,

I have been running Mallory Unilite distributors for many years and have had similar issues with the cars dying as you described. I do believe that the module is your issue and I would suggest that you buy a replacement and stash it in the glove box for a "just in case" day. Make sure you by a New unit that is manufactured by Mallory and not a Chinese repop. I would also suggest purchasing and installing the filter that is offered by Mallory also.

Good Luck.....

Thanks, Jay

 

[Carolina_Mountain_Mustangs]

I would loosen the screws on the ignition switch that is bolted to the top of the steering column under the dash. Not taking about the key lock. When you turn the key there is a rod that goes down to turn the ignition switch on. It might need a tiny adjustment to make sure it always stays on. I think you would just slightly loosen the bolts and move the switch toward the driver just maybe a 1/16" of so. Seems like the bolts are 3/8" or 7/16" hex.

Have attached couple examples out of Ford manual.

IMG.pdf

IMG_0002.pdf

 

[mbrew2]

MB,

I have been running Mallory Unilite distributors for many years and have had similar issues with the cars dying as you described. I do believe that the module is your issue and I would suggest that you buy a replacement and stash it in the glove box for a "just in case" day. Make sure you by a New unit that is manufactured by Mallory and not a Chinese repop. I would also suggest purchasing and installing the filter that is offered by Mallory also.

Good Luck.....

Thanks, Jay

Thanks for the heads-up about the Mallory distributor. I have ordered a new module that should be here tomorrow. Hopefully that will solve my problem.

 

[TheRktmn]

i had a similar issue years ago with my 70. Turned out to be a loose terminal on a coil wire. It acted exactly like a switch...basically it was.

I had a similar problem years ago when I was wrenchin' for a living. Customer's car would shut off at cruise - any speed, just constant RPMs. No coughing like a fuel issue, no back firing like a timing or timing chain issue.

I finally found a bad wire on the pickup module in the distributor - the vacuum advance would move it to just the right spot and one of the wires would 'open' causing the car to shut off. As soon as the engine died the vacuum went away, the wire would make and you could start the car again.

I found it by attaching a hose to the vacuum advance and very slowly giving it vacuum to move the plate while idling.

Electrical gremlins can drive you nuts!

 

[Hemikiller]

Verify and re-verify you have a good, solid battery -> fender apron -> engine block ground path.