ignition module problems
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ignition module problems
Hello everyone, I'm new here so please excuse if don't do something right. I am stumped with a problem on my 78 F-100, It keeps burning up ignition modules. Any feedback will be greatly appreciated.
Posting Legend
Joined: Sep 2001
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How often are they failing? What brand of module are you using? The best ones are Motorcraft, more $$ but it will pay for itself in fewer hassles and preventing fuel waste. Lifetime warranties will not pay you for wasted fuel or your time. Mount the module 1/4" off the fender to let cooling air under it. I use 5/16" hex nuts as spacers.
Check your coil and primary circuit ballast resistor also.
Welcome to FTE!
Check your coil and primary circuit ballast resistor also.
Welcome to FTE!
Freshman User
Joined: Nov 2001
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From: Phoenix USA
Check the wiring harness between the module and the distributor. I have found in the past that as little as 5 Ohms resistance in the ground (black) wire to cause the reluctor and or the module to burn up quickly. These parts should last indefinitely, so even if it is burning up only once a year, something is wrong. Try to stay away from the parts made by Wells.
Fleet Mechanic
Joined: Mar 2004
Posts: 1,398
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From: Hesperia, CA
Mil1ion is right, make sure that the replacement module is the same color code as the one you take off. Do not intermix Dura Spark I and Dura Spark II components. Make sure the engine, body, and frame are physically bonded together to make a good ground. I have been running my 77 for 27 years and had one coil burn out in all of those years, you definately have something wrong. Good luck, Gary
Posting Legend
Joined: Sep 2001
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Aftermarket modules can fail in as little as six months even with perfect wiring. Use Motorcraft modules only. Wells, Standard, Borg Warner, Parts Master, etc etc are all junk.
The ignition system is grounded thru that ground wire to the distributor.
The ignition system is grounded thru that ground wire to the distributor.
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Posting Legend
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Post number 18 in the Read First: FAQ section at the top of the forum has links to diagrams and descriptions of various ignition systems.
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When the (what I think was the original) module went out I replaced it with a Wells F102 module from Auto Zone. It lasted for a few months then the problem started again, I went and had it checked and it was bad, so they give me another one. Since then it has been more frequent to the point of I put one on one day the next it has went out again. My last effort was replace anything I thought might be causing this.. pickup coil, coil, voltage regulator, and yet another new module all at the same time, with the same result the very next day. I also left out earlier that my truck has a 300 c.i. 6 cyl. 2 wd 3 speed. The truck has been in my family almost since new and has always been taking good care of and well maintained.
Fleet Mechanic
Joined: Mar 2004
Posts: 1,398
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From: Hesperia, CA
You might best find a pick-a-part and get an original and try it. But remember that you replaced the original because it went out. The probability that the wiring is bad is a real prospect here. Check all of the connectors for corrosion, intermittant wires, etc.. I have done a lot of modifications to the Dura Spark system to try to improve performance and the only problem that I have ever encountered is with the coil. You definately have something that is blowing these modules. I have heard several bad comments about the Wells unit, but haven't any personal experience with them. Again good luck, gary
Posting Legend
Joined: Sep 2001
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I have found almost all of my Motorcraft ignition modules in the junkyard or on vehicles I have parted out. Usually the junkyard units were for $5 or less. So far all of them have tested good and worked perfectly (knock on wood). I do have one (tested good) unit that was a brand new Cobra repli-car take-off that cost me $12 on eBay. It will be going on my project truck. It is the only vehicle I have now running the Duraspark system. All the rest use those %@$#&* computerized coil packs. I have not needed any more DS-II units since I replaced all of those junk brand units with them. I also have a brand new & tested BW unit replaced under warranty for a spare.
Mountain Pass
Joined: Jan 2005
Posts: 112
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From: East Tennessee
I've got a 78 4X4 with a 351M that does the exact same thing. Thanks everyone for the help. I've lost count of all the ign. modules I've put in this thing the last couple of years. I was starting to pull my hair out. Thanks y'all. This thread will be a huge help.
Later
Later
Posting Legend
Joined: Sep 2001
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Heat is the major culprit which is why FORD issued a TSB about mounting them 1/4" off the fender.
I have even had one fail right in front of my eyes. I had a van sitting idling once on a hot day while talking to some people. It was running smoothly when all of a sudden the idle dropped and sounded rough. When I got into the van and drove away it drove very poorly. I removed the module the next day and it tested bad. A junkyard Motorcraft module I had picked up solved the performance issues and I kept the "warranty replacement" module for a spare.
I have even had one fail right in front of my eyes. I had a van sitting idling once on a hot day while talking to some people. It was running smoothly when all of a sudden the idle dropped and sounded rough. When I got into the van and drove away it drove very poorly. I removed the module the next day and it tested bad. A junkyard Motorcraft module I had picked up solved the performance issues and I kept the "warranty replacement" module for a spare.