How to test an ignition module
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Senior User
Joined: Jan 2000
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From: Virginia Beach
How to test an ignition module
I have a 78 F-150, 4x4, 351M, C-6.
It still has the original duraspark ignition module with about 160,000 miles.
It is my daily driver, and I like to replace things, particularly electronic stuff, before it leaves me sitting on the side of the road rather than after.
Is there a way to test the module? The truck was running rough, and I'm trying to isolate if it was the timing, ignition module, distrubutor, etc.
Would it be good to just go ahead and replace it anyhow? Almost everything else has been replaced: ignition switch, alt, dist, coil, volt reg, etc.
Do Ford dealerships still regularly stock these, or do I need to go with aftermarket parts from Autozone, etc?
TIA,
Sam
It still has the original duraspark ignition module with about 160,000 miles.
It is my daily driver, and I like to replace things, particularly electronic stuff, before it leaves me sitting on the side of the road rather than after.
Is there a way to test the module? The truck was running rough, and I'm trying to isolate if it was the timing, ignition module, distrubutor, etc.
Would it be good to just go ahead and replace it anyhow? Almost everything else has been replaced: ignition switch, alt, dist, coil, volt reg, etc.
Do Ford dealerships still regularly stock these, or do I need to go with aftermarket parts from Autozone, etc?
TIA,
Sam
Moderator
Joined: Jan 2001
Posts: 56,977
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From: Virginia
You can get a spare and keep it handy, but I would not replace the original unit. Sometimes the unit you replace it with, has problems the old unit didn't. You have to work at a factory to know what I am talking about. They pretty much throw things together. Most of the time they work ok, but some have problems. If you find yourself with one that has lasted many years, I would consider that you happened to get a good one, and it should be cherished. This goes for all the electronics in the vehicle. They are pretty much non-wear items.
If you get a spare, get one from the junkyard, or order one from Ford. Some people haven't had success with aftermarket units.
If you get a spare, get one from the junkyard, or order one from Ford. Some people haven't had success with aftermarket units.
Post Fiend
Joined: May 2006
Posts: 10,007
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From: Central Florida
Well, the first check is to look for a really nasty streak of goo running down the inner fender below the module. Then if it's running rough, you can poor ice water on the module and if it starts running better, it's time to replace the module.
However, after doing it myself, I would recommend replacing the DSII for an MSD ignition. It's not really plug and play, but it is an easy swap. After going to an MSD, you will not have the issues and better spark.
However, after doing it myself, I would recommend replacing the DSII for an MSD ignition. It's not really plug and play, but it is an easy swap. After going to an MSD, you will not have the issues and better spark.
Moderator
Joined: Jan 2001
Posts: 56,977
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From: Virginia
Oh, with the problem and the module testing, you can take it to autozone and they will test it on their machine. If you think it's heat related, put the module in the windshield in the sun and let it get hot before they put it on the machine.
Posting Legend
Joined: Sep 2001
Posts: 30,255
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My local O-Reilly store has a good testing machine that has always been accurate for me. When you remount the module after testing mount it on 1/4" standoffs to keep it cooler. There is a Ford TSB on this modification. If you need a replacement get a genuine Motorcraft module, not one of the aftermarket parts even if they do have a lifetime warranty. Replacing the module every year or so is not worth the hassle and wasted fuel. I get my Motorcraft modules out of the salvage yard and just have them tested. It has worked for me and now I have plenty of spares.
Keep the DS-II system. It is superior to the MSD system and mega cheaper. The OEM system can also be tested at the parts store without spending mega bucks shotgun testing some aftermarket system.
Keep the DS-II system. It is superior to the MSD system and mega cheaper. The OEM system can also be tested at the parts store without spending mega bucks shotgun testing some aftermarket system.
