This is on my '86 5.0 bronco. Posting here because not many folks in the bullnose forum have experience with the EFI system.

I read a lot of similar threads last night, seemingly a common problem except that most folks have a poor running engine to begin with.

Mine is DEAD. No spark, won't start at all.

fuel pumps are running and it has good fuel pressure while cranking.

Tachometer is working, Replaced TFI unit with a spare because that's always a suspect....

I have power to the coil. But the negative side isn't flashing. (It's not firing a spark, duh)

The only code I get is a CM code 18. Spout grounded- IDM circuit failure.

I started running through the factory service manual diagnostic checks. Everything seemed ok except for the secondary coil resistance. Lower than what the factory or MSD says it should be. By about 50%. Bad coil? I'm not convinced.
Got proper voltage on pins 2, 3, & 4 of the TFI plug.

Now I've made it to the PIP sensor... The distributor is not quite a year old. Everything under the rotor looks fine. Ran out of daylight today but I'll be testing it tomorrow.

Ignition switch seems fine. I dropped the column and checked it out. Was new within the last couple years as well.


Soooo, I'm kinda stumped.

 

Take your distributor cap off and crank the engine over, make sure your distributor is turning. Ask me how I know...

 

If you have power to the coil with the ignition switch turned on, which it sounds like you tested. Either the ICM which you tried a different one, the coil, or the PIP in the distributor.

Where did you get your year old distributor, which contains the PIP?

In your shoes I would try a coil next first, due to the complexity of finding a good distributor or changing the PIP in the distributor. If you are sure the ICM you tries is good.

 

My distributor came from O'Reilly's. It was installed with my new motor last Christmas. So if that's what it turns out to be, I should still have the receipt and warranty.

I did verify that the distributor still turns and that I cannot turn it by hand. Sheared pin or broken shaft was one of my initial thoughts as well.

I mayyyy swap the coil, but only if I don't come up with something else first. I've confirmed that the coil isn't being properly controlled, so it's not the source of the problem as of yet.

 

Your stator in the distributor is the issue IMO and damn straight it might not be turning if you replaced the distributor
That is what they do best (shear what would be the roll pin) they used a solid chicken sheet pin on mine, and it broke causing your symptom (died while driving)
Good luck

 

It's turning with the engine. I can not turn it by hand, like if the pin sheared.

I'm hopeful that it is the problem, but I wasn't able to test or confirm that today.

 

Well it's not the pip/ distributor. Unless the new one I just swapped in is also bad out of the box. (Really Sucks you can't even trust new parts these days)

So, I'll start back through it again tomorrow/ this weekend to make sure I didn't miss anything.

But NOW, it's gotta be a wiring problem, right?

Time to bust out the ol BOB...

 

What is a BOB?

Did you check for spark again or just try to start it? I always figured if you had power to the coil with the ignition switch turned on, the problem had to be the ICM, the coil, or the PIP in the distributor, barring a bad wire around the coil or distributor area or a bad rotor in the distributor. This would just mean you should get spark and not rule out a fuel delivery problem.

I am currently dealing with a 1990 Ford Taurus that lost ignition and a new ICM and coil didn't fix it. I haven't pulled the distributor yet but I may learn something before it is fixed.

 

BOB is a Break-Out Box. It hooks inline to the EEC wiring harness and allows you to test each pin circuit with a multi-meter. Of course you need to know what pins are supposed to be doing what... that's where you need a factory service manual... anyway, they can be extremely helpful with these kinds of problems, but nowadays, they're hard to come by. I got lucky and found one locally through connections, but they come up on eBay from time to time.


I only tried to start it. was already dark and starting to rain on my back. out of time and out of energy for tonight. time to sit at the computer and enjoy a drink... and contemplate how far into this I have to go before I throw in the towel and convert it to a regular ignition & carburetor.

tomorrow ill go back through and recheck the powers & Grounds, bench test the coil.... then????

 

OMG no, say it isn't true. I have one too (a breakout box) but have not used it for years and years. I use a spare test distributor to test stators. Ford used to send us crate motors that were complete. I saved a few distributors over the years and a few coil packs for the EDIS ones. Using known good parts is one of the better, easier ways to diagnose problems.
Good luck

 

Bench testing the coil, I couldn't get it to fire a spark.
(Hooking power to +, shorting - to ground momentarily)

Thinking to myself, "Even if the computer or wiring harness or anything else is broken, I am the only thing controlling it. And it's not sparking.... Hmmm"

Go out to Oreillys, get a coil, stop for a hamburger on the way back, install coil after reading resistance values. Get all set up to check for spark control again, and as soon as I bump the starter, the MFer lights right off....

I'm always grateful when it's something easy. But gah-lee! Hours of frustration wasted digging way too far down the rabbit holes.

This is actually the first time I've ever experienced a bad coil. On any vehicle.

So.... Live & learn I guess. I'm still surprised the way it just died. A coil usually doesn't go out like that from what I've seen/ read about other people dealing with.