89 Bronco no spark ignition

[mikefamig]

That is a very valid and excellent point to ponder.

Even though that power relay powers up so many other things, the ignition primary is isolated from the rest by that fusible link, so all you have to focus on to find the source of what cooked it is that white and blue wire.

Inspect around the ignition coil. The primary wires there tend to get frayed and could easily touch against metal somewhere. The frame of the coil and the radio suppressor are the most susceptible areas.

I have noticed that there is a capacitor mounted next to the ignition coil that has heat damage on it's insulation. In an old point type ignition that would be attached to the coil to suppress radio noise but this one has a wire that goes back into the wiring harnes so I do not know what it is attached to.

I will test the cap with an ohm meter later today but can you guys tell me what it does.

EDIT:

I just noticed in the wiring diagram above that there is a noise suppression cap on the coil that connects to the and that must be it. It appears to go back into the harness and connect to that white/blue wire. I'll just replace it knowing that electrolytic capacitors have liquid in them that dries up over time which can cause them to short.

 

[L\Bronco]

I have noticed that there is a capacitor mounted next to the ignition coil that has heat damage on it's insulation. In an old point type ignition that would be attached to the coil to suppress radio noise but this one has a wire that goes back into the wiring harnes so I do not know what it is attached to.

I will test the cap with an ohm meter later today but can you guys tell me what it does.

EDIT:

I just noticed in the wiring diagram above that there is a noise suppression cap on the coil that connects to the and that must be it. It appears to go back into the harness and connect to that white/blue wire. I'll just replace it knowing that electrolytic capacitors have liquid in them that dries up over time which can cause them to short.

Hey Mike, that cap is connected to the power feed that goes to the coil pos.
Every time the coil is turned off (to make spark) there is a voltage spike in the power feed. The cap absorbs that spike.
If it shorts, it will burn that fuse link.
Cheers

 

[mikefamig]

Hey Mike, that cap is connected to the power feed that goes to the coil pos.
Every time the coil is turned off (to make spark) there is a voltage spike in the power feed. The cap absorbs that spike.
If it shorts, it will burn that fuse link.
Cheers

Well I know that it is not completely shorted due to the fact that the engine runs but it can be partially conducting to ground causing the circuit to heat up.

I'll change it asap.

 

[mikefamig]

So the capacitor is not available anywhere that I can find online and the dealer, and I quote, said "Ford does not care about your 1989 Bronco".

The dealer did however give me a part number

E0TZ-18832-A​

that I still can not find and these parts have a shelf life anyway. I need to learn if I can get a modern part that will do the job.

The car runs with the part removed but the radio has a loud buzzing noise as I suspected so the cap is doing it's job at the present time and is probably fine but I worry it may have an intermittent problem that caused the fusible link to melt.

 

[L\Bronco]

So the capacitor is not available anywhere that I can find online and the dealer, and I quote, said "Ford does not care about your 1989 Bronco".

The dealer did however give me a part number

E0TZ-18832-A​

that I still can not find and these parts have a shelf life anyway. I need to learn if I can get a modern part that will do the job.

The car runs with the part removed but the radio has a loud buzzing noise as I suspected so the cap is doing it's job at the present time and is probably fine but I worry it may have an intermittent problem that caused the fusible link to melt.

In my experience, they are pretty durable, (unlike the ones on the board in the PCM.
Its rare to see one fail. just go to a local "U pull it" (do you guys have those?)
There are caps on most fords with the E-core coil, (5.0-5.8) mustang, crown vic, f series, bolted to the coil bracket. should be nearly free.
Like I said, its a rare occasion when they fail in a way that causes a concern.
Hope that helps.
Cheers

 

[Motech]

I agree, those capacitors don't fail too often. In fact, I do not ever remember one failing on a Ford in my near 40-year career. (Chevy yes)
I've had the wires get frayed and short out against metal when they've been moved around to places they don't belong, but never outright failed itself.

 

[wyo58]

I just took it out on the road for just a few miles and all is well. I felt around after the ride and the wires are nice and cool. I'll snoop around some more tomorrow. Time to go put my feet up now.

Hard to say what caused it to torch, however you put the same size back in so your protected. Like motech said check all The wires in that supply circuit for frayed or cracked wires that could have touched a ground source. Also where those wires go into connectors that have alot of wires where two or more could touch each other. I have seen the links just quit working but yours was clearly torched meaning somewhere it grounded out. Good job finding the problem! Now keep going and find why it became a problem.

 

[mikefamig]

Hard to say what caused it to torch, however you put the same size back in so your protected. Like motech said check all The wires in that supply circuit for frayed or cracked wires that could have touched a ground source. Also where those wires go into connectors that have alot of wires where two or more could touch each other. I have seen the links just quit working but yours was clearly torched meaning somewhere it grounded out. Good job finding the problem! Now keep going and find why it became a problem.

So as I think I said earlier I did find that the insulation was burned from the wire at the connector to the noise suppression condensor mounted near the ignition coil. It was burned to the extent that there was a half inch or so of bare wire which could potentially short but was OK as it was positioned.

I cut the connector from the wire, stripped the damaged insulator, replaced it with some heat shrink tube and soldered the connector back to the wire end. I don't drive the Bronco much but time will tell if that was the culprit and the only culprit.

Thanks all again, with any luck this is the end of this episode.