Blowing ignition control modules
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Senior User
Joined: Feb 2007
Posts: 128
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From: Worcester
Blowing ignition control modules
I had posted a thread earlier about my 1978 f250 with a 351m. The truck would run erratically after warming up, Someone suggested that I sawpped out the ignition control module because it was probably bad or overheated. I did, and the truck ran great and i took it for a 45 min. drive with no problems. Now, i am back to where i started. The truck runs fine until it warms up and then it runs bad after...i think i blew the module again. Any ideas? how would i test for a short etc.?
Post Fiend
Joined: Jul 2004
Posts: 8,786
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From: Northern California
What brand of module did you get? Some of the off brands from china are bad right out of the box, or go bad in a few days.
Ford still makes Blue grommet motorcraft modules, but they are not cheap. $120
Borg/Warner also makes modules, and they are pretty good brand as is wells brand. Not as good as the Motorcraft one though.
The cheap ones at autozone, or O'rileys you need to stay away from. If you do buy them there, go for the most expencive one they have, with the best warrantee.
Hope this helps.
Ford still makes Blue grommet motorcraft modules, but they are not cheap. $120
Borg/Warner also makes modules, and they are pretty good brand as is wells brand. Not as good as the Motorcraft one though.
The cheap ones at autozone, or O'rileys you need to stay away from. If you do buy them there, go for the most expencive one they have, with the best warrantee.
Hope this helps.
Certified Thread Hijacker
Joined: Aug 2001
Posts: 14,441
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Definately get the Motorcraft module... DY-893 about $75 at Rock Auto
I would also check to see how much voltage you're getting to the module, too much or too little will throw things out of whack.
Josh
I would also check to see how much voltage you're getting to the module, too much or too little will throw things out of whack.
Josh
Junior User
Joined: Mar 2009
Posts: 57
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From: Central Indiana
I second the magnetic pick up in the distributor. I had the exact same problem on my 78 Bronco w/351M. Drove me crazy trying to figure it out.
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Postmaster
Joined: Jan 2005
Posts: 3,876
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From: Hollister MO
I think i would just change the distributor, you have to disassemble the distributor to change the pick up. Its a 30 year old distributor.
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Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
I actually agree with changing the distributor, if it's original.
The centrifugal advance springs could be worn out and shot, among other things.
If you do replace it, go for the better one. Don't buy the cheap stuff, as it will come to bite you later. Especially if you plan on keeping the truck for a long time.
The centrifugal advance springs could be worn out and shot, among other things.
If you do replace it, go for the better one. Don't buy the cheap stuff, as it will come to bite you later. Especially if you plan on keeping the truck for a long time.
New User
Joined: Oct 2010
Posts: 4
Likes: 0
i melted down the module in my 79 and replaced it with a house brand from oreillys and the truck runs just fine and has been for awhile now, but i do plan on getting a borgwarner or motorcraft one when i redo the truck here in the next year or so
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Wells and Borg/Warner are decent in my experience. However they still require a little cranking to get the engine going.
Motorcraft Modules are the best in my experience. Usually start with first turn of the key.
Motorcraft Modules are the best in my experience. Usually start with first turn of the key.
Lead Driver
Joined: Jul 2017
Posts: 9,545
Likes: 1,156
From: San Jose, CA
Even though this is not the '87 forum, some things will be the same. Since the ignition module has nothing to do with the starter cranking the motor, it will be in some other part of the system.
When you get a no-crank condition, do you at least hear the starter relay give you a loud click there on the fender? Or do you get nothing at all?
When this happens, do other accessories still work? We had a recent discussion about bad battery cables. But when they're bad, usually nothing works in the cab either. When it won't crank, try the heater and headlights and stuff like that. If those work, or not, then we can start to narrow it down.
Does your truck have a manual transmission, or automatic? With the manual transmissions, do they have a clutch-interlock switch that does not let you start the truck unless you have your foot on the clutch?
If either of those, sometimes the clutch interlock, or an auto's neutral safety switch can die or come out of adjustment and keep you from starting the vehicle. Everything else will work, but the starter will not spin and crank the engine.
Good luck. Hope that helps you narrow it down some.
Paul
When you get a no-crank condition, do you at least hear the starter relay give you a loud click there on the fender? Or do you get nothing at all?
When this happens, do other accessories still work? We had a recent discussion about bad battery cables. But when they're bad, usually nothing works in the cab either. When it won't crank, try the heater and headlights and stuff like that. If those work, or not, then we can start to narrow it down.
Does your truck have a manual transmission, or automatic? With the manual transmissions, do they have a clutch-interlock switch that does not let you start the truck unless you have your foot on the clutch?
If either of those, sometimes the clutch interlock, or an auto's neutral safety switch can die or come out of adjustment and keep you from starting the vehicle. Everything else will work, but the starter will not spin and crank the engine.
Good luck. Hope that helps you narrow it down some.
Paul