Engine shutting off?

[cheatham]

I need some input, guys. Lately my trucks has been randomly cutting off while driving. It does this frequently while idling, and sometimes while driving. I turn off the key, and restart and it fires back up without hesitation.

Last year the same thing happened and I replaced the fuel pump and filter and this fixed the problem. I looked under the hood and the filter is full of gas and looks clean, so that doesn't seem to be the problem this time.

I need some help here, this can be very dangerous when it dies pulling out into intersections.

Thanks in advance,
JP

[SWEET7T]

sounds like the electronic spark control module is going bad. I had an old Jeep that did exactly the same thing, just randomly shut off, just like I had turned the key. It did it mainly while idleing, but sometimes while I was driving.
Good luck

[cheatham]

What is and where is the electronic spark control module. I am not familiar with this.

[rickspickuppart]

I agree either the module or the pickup coil, they are in the distributor (HEI).

Shawn

[mtdave2]

my vote is the pick up coil! but its right next to the module. that is ofcourse if you are running an hei..

[O'l Buck]

You might also check for large vacuum leaks.......my 2wd was recently acting sorta like yours is.

[SWEET7T]

If you have the HEI distributor:
Remove the cap and rotor. The module is a little box, on the opposite side of the vacuum advance unit. The pick-up coil is just (counterclockwise) of the module.
To check the pick-up coil... Disconnect the 2 wires. Connect an ohmmeter to each terminal of the connector and ground (doing one terminal at a time). You should get an infinite resistance. Then, connect the ohmmeter (each lead, to each terminal, no ground this time). Opperate the vacuum advance, the ohmmeter should read between 500-1500 ohms. If either fails, replace your pick-up coil.

The ignition module can be checked, but requires special equipment. Just take it to a shop somewhere. Many shops have the stuff to do it.

[cheatham]

Thanks for all the replies.

I do not have hei in my truck (it is laying in the closet) I will check the coil etc after work. I changed the points a while back and can't remember what else I put in... Maybe I should just go ahead and put on the hei if I find that something needs replacing. O

Any more ideas always appreciated.

JP

[70short]

YES! Install the HEI! Dont forget to change plug wires, Ck sparkplug gap. and run 12v switchable to the coil. You will be much happier!

[BigBlockBurris]

I had the same problem you describe in my 72. It would just cut off at random times and would always start right back up. When mine cut off I lost all power (Radio, lights ...). It was like the whole truck would die and sometimes it would even come back on its on. I scratchesd my head for a while but finally figured out I had a burnt up ignition switch. When I pulled it out you could see where it had gotten hot. Replaced it and the plug on the harness(also melted) and no problems since. Hope it helps.

BBB

[70short]

good point BBB! As old as these trucks are that would be A good thing to change and there not expensive.

[ddsmith]

Another possibility is the Red wire feed to the ignition switch from the battery may not be making good contact at the battery or the ignition. If you have a so-so connection and it heats up resistance takes off and eventually gets to hi for current to flow. When current stops so does the truck because that is where your distributor is getting power from. When you take the key to start you provide a full 12V to the coil via the yellow wire from the starter. Under normal running conditions the power is feed via a resistance wire from the bulkhead connector to the coil positive terminal which drops voltage to prevent points burn out. If everything else still works in the truck when it dies, then I'd look closer at this resistance wire as the possible problem.

[cheatham]

Yes, the accessories do continue to work when the truck dies. That is an interesting scenario ddsmith, and makes sence as to what is happening in my situation. I will be checking that too, later.

[mtdave2]

yep. perfect time to put in that hei. it only takes an hr at the longest.. easy install

[cheatham]

OK, 2 questions.

1. is this resistance wire the one that comes off the battery terminal as a separate wire and runs across the top of the radiator then back near the firewall?

2. I have the hei distributor, bare bones so to speak. what all new parts do I need to put it on.

Guess I could do a little research and find the answer, but It is easier to ask guys that have been there done that.....

thanks
JP

[ddsmith]

The resistance wire comes from the bulkhead connector and connects to the coil positive lead. When you do the HEI swap you'll want to remove that length of wire and run 12 gage wire from the bulkhead connector to the 12 V connector on the distributor. I'm including a link to the FAQ on this subject and once you read through it let us know if you need any additional information. HEI FAQ Good luck,
Don

[Phillip Johnson]

Are you sure someone didn't put Valvoline Maxlife in your tank?????

[Hooter]

Originally posted by Phillip Johnson
Are you sure someone didn't put Valvoline Maxlife in your tank?????

If that were the case the truck would have just stopped and not started at all LOL

[O'l Buck]

Since we are talking about points, when you check out your dizzy, pull the condenser off.......my cousin had a 74 F@rd with point type ignition that he had just put new points and condenser in and it up and died in Cheyenne one day........we spent the better part of the afternoon and part of the evening in auto zone's parking lot trying to figure that one out........turned out that the spot weld on the clamp on the condenser broke and it lost ground.

[SEVEND2]

Points, Coil, or HEI issues there, my points where going bad in my truck and it did the same thing. at stop signs and some times idleing. changed themn out tuned it up and good to go

[cheatham]

Well, I found the culprit- cracked choke pulloff. So it turns out it was a vacuum leak. Thanks for the help guys, and the link to the HEI install. I will be doing that this week if time permits.

[gonebad2]

I had the same thing happen on a 70 GMC I once owned. It was the exact same problem that BBB experienced; a bad ignition switch. An old guy that I know gave me some good advice. Human nature always makes us think of the worst case scenario. He said "when you hear hoofbeats, don't look for zebras, look for horses" His advice has saved me alot of time. Now, I always start at the basics and move onto the the most difficult component in a particular system.