Ignition issues?
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
When it rains it pours! I've been working out the bugs on my 75 F100 over my past few months of ownership, every time I think I have things all squared away another gremlin rears its ugly head.
Yesterday on the way home my truck just up and died, the engine completely cut out, I coasted over to the road side and confirmed i had fuel delivery, then I checked for spark and there was none.
After 45min of trying to start I called a tow truck, shortly after I was home I decided to try and start the truck, to my surprise the engine fired right up! (I wish I had waited a little while longer and saved myself the $85 tow fee) lesson learned.
Today I checked the coil and stator assembly as per instructions I found on here, both were in spec, at least while cold, maybe the readings would be different if checked at operating temp?
I have no way of checking the ignition module, at least none that I'm aware of. Against my better judgment I took the truck out today and drove around for 1hr, I surely expected it to die again but to my delight it never did. I'm not sure how to rationalize this.
What's the best way to proceed, short of just throwing parts at the truck. Is it possible this episode was just a fluke, or is it an indication of things to come?
From the research I've done on here the module, coil, or stator are the most likely offenders when the engine just cuts out (ign. switch was replaced a few months ago).
Yesterday on the way home my truck just up and died, the engine completely cut out, I coasted over to the road side and confirmed i had fuel delivery, then I checked for spark and there was none.
After 45min of trying to start I called a tow truck, shortly after I was home I decided to try and start the truck, to my surprise the engine fired right up! (I wish I had waited a little while longer and saved myself the $85 tow fee) lesson learned.
Today I checked the coil and stator assembly as per instructions I found on here, both were in spec, at least while cold, maybe the readings would be different if checked at operating temp?
I have no way of checking the ignition module, at least none that I'm aware of. Against my better judgment I took the truck out today and drove around for 1hr, I surely expected it to die again but to my delight it never did. I'm not sure how to rationalize this.
What's the best way to proceed, short of just throwing parts at the truck. Is it possible this episode was just a fluke, or is it an indication of things to come?
From the research I've done on here the module, coil, or stator are the most likely offenders when the engine just cuts out (ign. switch was replaced a few months ago).
1) Module overheats, engine dies. Module cools down, engine restarts almost at once.
2) Module overheats, engine dies. Module cools down, engine restarts in an hour...or so.
3) Sooner or later, usually sooner, the module overheats, BURNS OUT. Now the engine will not restart.
Taking the module to an autoparts store to be tested: Will test OK, unless it has burned out.
Engine heat, especially when radiating from the V8's red hot left exhaust manifold in the mortal enemy of these modules, that are located on the left fender inner apron.
When replacing, use some washers to space it further away from the apron, the more airflow, the better.
The modules used 1974 (only) and 1975 (only) were such turds, that Fords techs referred to DuraSpark as NeverSpark!
More Turbo
Joined: Sep 2003
Posts: 516
Likes: 27
So it would also help to put a sheetmetal screen between the module and the exhaust manifold. Most of the heat transfer must be radiant heat, and intercepting it is an easy way to stop the module from overheating.
I am thinking the fact that the 6-wire modules don't work on your truck means you have either a bad ground somewhere or else a broken wire that the 7th wire is substituting for.
R.
I am thinking the fact that the 6-wire modules don't work on your truck means you have either a bad ground somewhere or else a broken wire that the 7th wire is substituting for.
R.
Freshman User
Joined: Nov 2014
Posts: 39
Likes: 0
From: Idaho
I would suggest checking the wires that run on top of the manifold. I had the same thing happening to me. After three different duraspark boxes I dug deeper. The wires were melted. The fix I used was an msd ignition, got it off of ebay. Works great.
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Freshman User
Joined: Aug 2015
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I appreciate the suggestions guys! As of right now I'm back in business!
I plugged in the new module and the engine fired off with just a 'bump' of the key, even idled better than before, I drove around for an hour without any issues.
So all appears to be well....for now...until the next gremlin!
I plugged in the new module and the engine fired off with just a 'bump' of the key, even idled better than before, I drove around for an hour without any issues.
So all appears to be well....for now...until the next gremlin!
FTE Emeritus
Joined: Jan 2006
Posts: 2,288
Likes: 200
From: springfield Missouri area
Just thought I would add something to check. My truck would die like that and it was the connector on the coil. Could wiggle it and it would fire right back up. Was not really corroded but the copper was discolored. Could scrape it and it would last a while. But would eventually do it again. Finally changed connector.
Elder User
Joined: Sep 2014
Posts: 862
Likes: 7
From: like subarctic, brrr man!
Just thought I would add something to check. My truck would die like that and it was the connector on the coil. Could wiggle it and it would fire right back up. Was not really corroded but the copper was discolored. Could scrape it and it would last a while. But would eventually do it again. Finally changed connector.
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Freshman User
Joined: Aug 2015
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Moose, a fellow co-worker of mine made that same recommendation when this issue first came about, but my coil doesn't use the 'horseshoe' connector, it uses threaded studs w/nuts.
I don't think the 'horseshoe' connectors always make the best connection, and can sometimes lose contact, as you well know. IMO the coils with studs/nuts make for a much better connection.
I don't think the 'horseshoe' connectors always make the best connection, and can sometimes lose contact, as you well know. IMO the coils with studs/nuts make for a much better connection.
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Freshman User
Joined: Aug 2015
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While I'm on the topic of ignition modules maybe someone can clear a few things up...
I've read conflicting information on how the module is grounded, some say the modules black wire grounds the module through the distributor, others say the module is grounded through its mounting surface on the fender, which is correct?
Also, everyone mentions how sensitive the modules are to heat inside the engine bay, which begs the question why are they mounted in the engine bay in the first place? inside the cab would seem a much more logical choice to me.
I've read conflicting information on how the module is grounded, some say the modules black wire grounds the module through the distributor, others say the module is grounded through its mounting surface on the fender, which is correct?
Also, everyone mentions how sensitive the modules are to heat inside the engine bay, which begs the question why are they mounted in the engine bay in the first place? inside the cab would seem a much more logical choice to me.
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Freshman User
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All the schematics I've viewed have no indication of the module being grounded through its case, only the black wire is shown as ground.
My dad had an 80's Ford truck and I recall the module being mounted to the inner wheel well, which was made of plastic.
Certainly it wouldn't hurt anything to ground the module to the fender, but it doesn't appear to be necessary.
My dad had an 80's Ford truck and I recall the module being mounted to the inner wheel well, which was made of plastic.
Certainly it wouldn't hurt anything to ground the module to the fender, but it doesn't appear to be necessary.
Laughing Gas
Joined: Nov 2013
Posts: 1,207
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From: S.E. Louisiana;so far USA
Today's computers are often in the passenger compartment.
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Freshman User
Joined: Aug 2015
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After hearing about all these heat related issues with the modules 'under the hood' factory location I'm seriously considering relocating mine inside the cab.
I honestly don't think it would be very difficult, just a matter of taking the modules connecting wires and pulling them back through the firewall, then finding a place to mount the module.
I would probably mount the module where a trailer brake would typically mount, just under the headlight/wiper switch, on the bottom of the dash.
I honestly don't think it would be very difficult, just a matter of taking the modules connecting wires and pulling them back through the firewall, then finding a place to mount the module.
I would probably mount the module where a trailer brake would typically mount, just under the headlight/wiper switch, on the bottom of the dash.
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Freshman User
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Curiosity got the best of me so I went out and unbolted the module from the fender and went to start the truck....the engine fired right up!
So it's pretty obvious the black wire is doing the grounding duties, not the modules mounting surface.
So it's pretty obvious the black wire is doing the grounding duties, not the modules mounting surface.