The gray ICM will not cause the problem you're describing.
The ignition coil creates a high voltage spark from the voltage build-up and instant collapse of the magnetic flux inside the coil. "Build up and collapse". That means "on" and "off". The ignition coil is constantly getting 12v from the Red and green wire. ICM controls the ground side of the coil by quickly turning it on and off. The PIP (inside the distributer) tells the ICM to turn the coil on and off.
From what I saw in your video, that looks like a 100hz spark. That's faster than any relay can operate. It's definitely something electronic telling the coil to turn on and off 100 times a second.
This may sound drastic, but you may want to consider cutting (or de-pinning) the #1 wire on your ICM (The PIP input wire) and see if your constant spark problem continues. Leave enough wire so you can splice it with a butt-splice after the test. There is something that is causing the ICM to fire the coil 100 times a second.


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Just out of curiosity I checked the frequency of the coil wire current. 67kHz. That's 67,000 Hz.

FWIW: I was mistaken about the 43 ohms to ground in the ignition harness. When isolating the harness I had pulled the wrong maxi fuse in the power distribution box. The 43 ohms to ground is upstream of the fuse. Harness good with correct fuse pulled. In my view this has nothing to do with my issue.

Unpinning the #1 PIP from the ICM connector looks like I'd have to destroy the silicone seal. Cutting not off the table.

Wanting to unplug the tachometer. Really didn't want to pull the instrument cluster to do it. On the schematic provided early in this thread I see two connectors C101 and C202. Locations? If I had access to the other pages of the publication the schematic came from it might be easier to find one

 

Hey, I was only off by a factor of 670.
These pages came from the 1994 Ford f-series EVTM FSM. Considering your knowledge, tools, and skill set, you would be better off purchasing the digital PDF off eBay for $35. C101 is you 42 pin main engine harness connector. C201 is your 65 pin firewall pass through connector. Pulling the instrument panel is a lot easier than playing with those connectors.
IF you can monitor the frequency of the negative side of the coil, then I assume you have an o-scope. What is the PIP sensor doing when the engine is off?

 

ohms on a ground circuit wont mean much, you need voltage drop test
Which on a ground , it depends on what its for and hwo long it is and how many connections

 

It's a long thread, I might have missed it, but have you tried wiggling the harness while the problem is occurring to see if it goes away?

 

I wonder if the ignition switch contacts for the "run" position are failing. I would try unplugging the "S" terminal wire from the fender mounted starter relay, and turn the key to the start position, to see if the symptoms change.

 

good tip to check

 

@Soup bean
It does its thing with or without S wire connected. I actually had my remote starter ready when I first went to check for spark. Step one.

I have wiggled the harness and wiggled again. You only need to get bit by a PIP grounding out against the foil shield one time to learn the importance of the test.

 

@Prototypemech
The instrument I used is just a DVM with a Hz setting. It can display voltage waveform but it is a cheap autoranging and can't be adjusted to to get a clear view of leading and falling edges. I do need to spend more money on a good Oscope.

I was going to check both PIP and SPOUT for a wave but now that is on my list for tomorrow.

 

My thinking was that if the ignition switch is failing, you could disconnect the wire going to the "S" terminal, then turn the key to the start position and see if the symptoms change. That may show if the contacts for the run position are failing, if the unwanted spark goes away in the start position.

 

I have tried to report every move but I have missed reporting a few.

I called in help from my ex- neighbor today. He is my age (on Medicare) and is a life long career Ford service technician. He once diagnosed the the bad distributor ignition pick up module in my brand new 1986 truck when it was under warranty and the dealer I bought it from couldn't.

He brought his TFI Rotunda test kit and it showed no faults. He did say that if the ICM was the wrong, push start type the machine wouldn't know it.

His response to the current flow demonstration? "Bizarre".

So then we spent a few hours shooting bull and catching up.

Back in the day all FOMOCO techs kept known good ICMs and MAP sensors in their toolbox.

Something in a very limited ignition scope is causing the issue. If I don't nail it down by Monday I'll be looking at parts. Maybe also the $35 PDF.

 

Wait.



Confirm your wiring is *FOR* a CCD ignition module, you have a CCD now but maybe the wiring is not for one

 

https://www.supermotors.net/registry/media/833750

Yes

GO down to "CCD Testing"
it uses a service manuals flow chart to diagnose, and the images inline are the referenced images/charts

 

Before I submit this morning's findings, a quick acknowledgement of @AuroraGirl 's contribution s. Thanks for pointing to Steve83's at Supermotors. Tons of information there on OBS trucks and Broncos.

Not sure if you were suggesting I check the wiring to insure my truck has CCD wiring or if that was pasted content from Steve83. Regardless, I can confirm that the truck is CCD. Still don't know how to determine if I have the correct ICM.

And the problem with most all the ICM testing on the truck is it is aimed at diagnosing a no or intermittent spark. Problems I run into on factory step by step (fan of step by step) is three steps in and you need a dealer proprietary test harness. Then I'm left trying to comprehend exactly what they are actually testing and then figure a work around using t-pins and back probing connectors.

On to today's surprises. When setting up to test the key switch to start with S-wire disconnected I needed to get my spark tester where I could see it from the driver's seat. I substituted a longer plug wire in place of the coil wire. No current flow even if I tightened the tool gap considerably. Coil wire= 7000 ohms, plug wire= 14k ohms.

Not sure if I reported or even checked this before but with current flowing,when the coil (-) is grounded the current stops. Unground and it starts again... "Most" times. If I poke at the coil (-) I can get the current to stay off... Sometimes.Note, grounding using test light.Bizarre.

Other suggestions followed up on. The PIP and SPOUT both deliver voltage pulse you would expect, engine running. Back probed at ICM connector

Other unrelated news. We had a heck of a storm overnight and I was disappointed to see the PCM connector all wet this morning. What a stupid set-up. Getting ready to storm again, gotta go

 

How are the terminal ends at your coil connections?
I changed mine because they were growing green corrosion, and I was troubleshooting an intermittent hard start. They weren't the cause of the hard start though.


How are your ground connections?
Posts 6 and 7 at this thread have a good list. The main ground cable from the battery negative terminal to the engine block and frame, has exposed wire strands at the frame connection.
https://www.ford-trucks.com/forums/1...nd-points.html