Ignition Module Failure on 94 5.0 with Distributor

JMBPE

Founding Member
Jan 14, 2002
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18
Bellvue, Colorado
I have gone through two ignition modules in two months. I have found no codes thrown and difficulty in isolating with power to the coil nothing coming back to the low voltage side of the distributor. distributor. With the last replacement I put in a #14 stranded wire from the module frame to chassis ground. Are these failures caused by a surge at start up? Is there a more substantial aftermarket module? (Both failures were NAPA). Am I on the right track?
 
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When does the failure occur?
Great question! Both times it showed no problem while engine was running just prior to the glitch. Failure could be pointed to startup, which then might point to the starter or solenoid as the source. The starter was replaced about 1,200 miles prior to the ignition module fiascos. I have beefed up the ground at the module with hopes that would take any surge or other transients safely to ground during start-up. I might be thinking about starter replacement again, but do not especially enjoy that procedure. Could be that carrying a spare ignition module in the trunk would be less painful than changing the starter again.

Thanks again
 
Starter........ignition module? One has nothing to do with the other.
What am I missing here?
An inductive device (such as a motor, especially with a partially faulted winding) is capable of producing a spurious voltage surge or spike. This often shows up at motor starting or when a high torque load is imposed on a motor. The voltage spike on a shared system can lead to failure of more sensitive equipment such as electronic modules, computers, video or audio equipment, etc. A voltage spike can be controlled by several approaches. The easiest and least costly remedy is by installing a low impedance path to ground that hopefully "bleeds" the surge to ground before it can damage anything. A similar approach is used in lightning protection systems. (See Ben Franklin for more on this). Sorry it that I fell into lecture mode. The 12 volt dc system in a vehicle is subject to the same problems as many other electrical systems.

Thank you for leading me to looking at the time of failure ... "start-up" and that put a whole different approach to the solution. The bottom line is that starter replacement is probably the next place to take this if more control modules bite the dust. Thank you also for your patience.
 
Starter........ignition module? One has nothing to do with the other.
What am I missing here?

He's actually spot on with this. MSD ignition systems are notorious for blowing on start up from sharp voltage changes.

What brand of ignition control module did you get? Parts have been all over the place in quality since Rona. GM is replacing 1000s of engines that are blowing because they went to substandard suppliers during shortages. I wouldn't over think it if it's one module.

Kurt
 
An inductive device (such as a motor, especially with a partially faulted winding) is capable of producing a spurious voltage surge or spike. This often shows up at motor starting or when a high torque load is imposed on a motor. The voltage spike on a shared system can lead to failure of more sensitive equipment such as electronic modules, computers, video or audio equipment, etc. A voltage spike can be controlled by several approaches. The easiest and least costly remedy is by installing a low impedance path to ground that hopefully "bleeds" the surge to ground before it can damage anything. A similar approach is used in lightning protection systems. (See Ben Franklin for more on this). Sorry it that I fell into lecture mode. The 12 volt dc system in a vehicle is subject to the same problems as many other electrical systems.

Thank you for leading me to looking at the time of failure ... "start-up" and that put a whole different approach to the solution. The bottom line is that starter replacement is probably the next place to take this if more control modules bite the dust. Thank you also for your patience.
Thanks for explaining this to an electrical moron, I'm aware of voltage 'spikes' I just don't know the peculiarities, I know 'the dump truck' (my self loading tow truck) has some type of diode between the positive wire and ground on the clutch pump, didn't make any sense to me at first till I read about the pump getting 'energized ' at start up and they are not designed to operate above 1500 rpms so you can imagine what happens when the pump is operating above that. :nono:
 
He's actually spot on with this. MSD ignition systems are notorious for blowing on start up from sharp voltage changes.

What brand of ignition control module did you get? Parts have been all over the place in quality since Rona. GM is replacing 1000s of engines that are blowing because they went to substandard suppliers during shortages. I wouldn't over think it if it's one module.

Kurt
I have had the problems with the NAPA version of the control modules that failed so catastrophically. At the last failure, I had an after-market module in my tool chest that came with an equipment package somewhere in the distant past (i.e. I don't remember exactly where.) If there are my modules that are more beefy, I would at least have it as a spare part to keep on board/
 
Thanks for explaining this to an electrical moron, I'm aware of voltage 'spikes' I just don't know the peculiarities, I know 'the dump truck' (my self loading tow truck) has some type of diode between the positive wire and ground on the clutch pump, didn't make any sense to me at first till I read about the pump getting 'energized ' at start up and they are not designed to operate above 1500 rpms so you can imagine what happens when the pump is operating above that. :nono:
There is no such thing as an electrical moron. I have spent my entire career chasing electrons and no one is capable of having a working knowledge of every aspect and detail of systems like these. That is why I so appreciated your question about when the failures took place. I opened a new perspective that I hadn't considered until you mentioned it. Thanks, again. I let you know of further problems as they come up.
 
There is no such thing as an electrical moron. I have spent my entire career chasing electrons and no one is capable of having a working knowledge of every aspect and detail of systems like these. That is why I so appreciated your question about when the failures took place. I opened a new perspective that I hadn't considered until you mentioned it. Thanks, again. I let you know of further problems as they come up.
Dude, I'm telling you I am an 'electrical moron'! I close my eyes plugging in the blow dryer. :doh:
Last time I changed a light bulb I had the fire dept on 'stand by' for two days.
I still have not turned it on. :(
 
Dude, I'm telling you I am an 'electrical moron'! I close my eyes plugging in the blow dryer. :doh:
Last time I changed a light bulb I had the fire dept on 'stand by' for two days.
I still have not turned it on. :(
I like that. We are digressing from Stang stuff, but take the words of a seasoned high voltage lineman: Working around live electrical systems need not be scary, but can be very unforgiving. Have a great day.
 
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"Steven" is my hero, the guy came up w/ go fast for less.
Glad they put up w/some prettyy ugly stuff & are still there for
the rest of us (me anyway). Not only do I have no automotive theory
I have the wrong, incorrect on it's electronics~
Thnx for ur humility JMBPE
 
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I would go OEM Ford for the ignition module and all electronics.
$60 at Tasca Ford plus shipping.
Put a thermal paste between the metal plate on the back and the mounting surface to help conduct the heat out of it. I would use the same thermal paste they put between computer processors (CPU) and the fan such as Arctic MX-4 or Arctic Silver (Amazon).

 
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Late to the party, but are you sure it's the modules failing and not the distributor? Anything is possible with today's Chinese quality parts (even OEM) but the pickup (PIP) in the distributor often goes bad about the same time a module does with the same symptoms (no start, and may stall out when hot). I've had poorly wired amps, oversized fog-lights, electrically noisy fans, lots of jump-starts, faulty starters that needed a hammering, and all manners of electrical mayhem over that time and never had it bake the TFI module.
 
I have not had problems with the fender mounted TFI's myself buy did many times with distributor mounted on the earlier Fords. I believe part of the issue is heat related which is why I suggested when replacing using a heat transfer paste between the TFI metal plate and the mounting surface.

If the wires look ragged I would also consider replacing the connector which is available aftermarket.
 
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