Burning through multiple TFI modules

[DarrenA]

Okay, it seems that I definitely have to check the coil when I get home from work. I will let y’all know how tests out. From my understanding, the oem primary resistance for the coil is supposed to be .44 ohms. That sound right? Electrical stuff ain’t necessarily my expertise.

 

[DarrenA]

1) Does the new TFI say Motorcraft on it? I would try to find a new old stock part.

2) It would be a good idea to troubleshoot. The stator in the distributor msg be the issue. To replace it you’re going to have to pull the distributor, use a gear puller to pull the drive gear, reinstall the distributor and reset timing.

It came in a motorcraft box but it does not have a motorcraft symbol, no. I was thinking that the stator might be an issue, I hope it isn’t because that’s a pain in the ass to do but we’ll see.

 

[RonD]

You can test ohms on a coil, and it will show if Coil is bad, but can not show if Coil is good
That's because Coils operate at higher temps, same for TFI or any ICM(ignition control module), they can test as "OK" but fail when in use at higher temps

So while you can test them to see if they are bad, there is no test for good

 

[gaz]

@DarrenA ,
I realise that you are looking hard at the Ignition Module but if I had performed the work on this power plant, I would carefully remove the last component I installed, making certain to...HOPEFULLY catch an installation mistake. Then carefully inspect all the wiring for that component, and the component itself.

I read that you have eliminated fuel as the culprit; did you try to start the engine using starter fluid and it failed?

Is your coil output consistent or is it's output intermittent? There is a ballast resister on the coil that I have experienced a no-start when the resister had failed. The old wires for the coil can also be a potential issue...all corroded inside the insulation.

Is your battery's static measured 11.86vdc or higher. Check all engine bay grounds, ESPECIALLY the battery cables and connections.

Don't give up, you will figure this out

 

[85_Ranger4x4]

You can test ohms on a coil, and it will show if Coil is bad, but can not show if Coil is good
That's because Coils operate at higher temps, same for TFI or any ICM(ignition control module), they can test as "OK" but fail when in use at higher temps

So while you can test them to see if they are bad, there is no test for good

In my case I was trying to use the original TFI E Coil instead of the round canister one with Duraspark igntion. It was just flat out the wrong one.

 

[DarrenA]

@DarrenA ,
I realise that you are looking hard at the Ignition Module but if I had performed the work on this power plant, I would carefully remove the last component I installed, making certain to...HOPEFULLY catch an installation mistake. Then carefully inspect all the wiring for that component, and the component itself.

I read that you have eliminated fuel as the culprit; did you try to start the engine using starter fluid and it failed?

Is your coil output consistent or is it's output intermittent? There is a ballast resister on the coil that I have experienced a no-start when the resister had failed. The old wires for the coil can also be a potential issue...all corroded inside the insulation.

Is your battery's static measured 11.86vdc or higher. Check all engine bay grounds, ESPECIALLY the battery cables and connections.

Don't give up, you will figure this out

Thank you for the tips and yes, fuel is 100% not an issue. I can see the gas being sprayed inside and I have also used starter fluid on it just in case.

 

[DarrenA]

Okay, another update here. I grabbed my multimeter from my garage to check my msd coil and right as I opened the hood, I noticed a little something. The spark plug wire connected to the coil had been completely separated from both of its boots (coil and distributor). All I can assume is that the steering linkage caught the wire, and tore it right off. This does make sense because I was mid-turn last night when it shut off on me. It was dark out and I was honestly too busy flipping shit to notice, so please give me a break lmao. Luckily, I kept all of my old spark plug wires and was able to reuse one. Truck started right up, and I drove it around my driveway for about 10 minutes back and forth to make sure everything was functioning correctly. The only thing out of the ordinary was that the engine stumbled for a couple of seconds in drive. I believe that's because my carburetor needs to be cleaned, but I got an ultrasonic cleaner for that fortunately. Anyway, I ziptied my wires so that they couldn't get caught up in the steering linkage and called it a day. I'll include a picture. As I'm posting this, the truck does work as it should. I'm not going to drive it much until my relocation kit gets here. Also, my new coil was closer to the proper resistance than the old one. Coming in at 0.45 ohms while the old one was 0.5 ohms. I believe oem is supposed to be 0.44 for primary resistance, secondary resistance was accurate for both. After this, I believe my coil is functioning correctly. I will let y'all know how my relocation kit installation goes and if I was found on the road dead again. I'll also include a few pictures of the truck, consider it my introduction to the forum. You'll notice that the oil dipstick probably doesn't look like a 2.8s and that's because it ain't. Turns out it goes to a 2.9 and the previous owner was putting almost 8 quarts of oil in it to make the thing "accurate". Sure made for an interesting oil change. If someone has a spare one lying around I'd be willing to buy it. Anyway, thank you to everyone for their input so far and I'll get back to here soon, hopefully with a fully functional vehicle.

 

[Uncle Gump]

Well...

I guess you were so tuned in to the module going bad... you didn't even think about checking for spark.

 

[DarrenA]

Well...

I guess you were so tuned in to the module going bad... you didn't even think about checking for spark.

Not my proudest moment…

 

[Uncle Gump]

Not my proudest moment…

We all have those now and then.

It is something that you will likely never do again.

Just glad you got your issue figured out.

If you don't mind... I'd like to hear your thoughts on the relocation kit when you get it.

 

[DarrenA]

O

We all have those now and then.

It is something that you will likely never do again.

Just glad you got your issue figured out.

If you don't mind... I'd like to hear your thoughts on the relocation kit when you get it.

Hopefully, and yes I will provide an update here once it’s installed with pictures.

 

[19Walt93]

I'd get something like these separators instead of bundling the wires together so you don't get induction crossfire. And still check the coil resistance to prevent a future problem.

 

[staindoutside12]

Man my brother and I have had an ignition/spark issue on his 1990 XLT 2.9 (manual 4x4) for 3+ weeks now. We feel like we are going insane trying to track this malignant problem down. We have tried every TFI module flavor; none have fixed the problem. It will be running fine then all of a sudden; it shuts off and won't restart.

I've figured out that there are some relays under the fuse panel, passenger side - under the hood with damaged brittle wiring. There's a 12 volt (i believe its key on) Red wire going to the EEV lV power relay and splices off to multiple other locations in the harness. He ordered some new pig tails but I made my own connectors for now. I am jumping 12 volts directly from the battery to this wire and it's the only way it will run and cycle the relays.

This wire is only getting 2.5 volts and some times 10 volts with a fully charged 12.9 volt battery. Peculiarously

 

[staindoutside12]

Auto correct cut 40% what I wrote out.
Basically I've tried loading up the parts cannon and I've tried chasing all the wires and replacing brittle wiring. The harness is in good condition everywhere else though.

 

[staindoutside12]

And it likes to fire the coil for no reason sometimes, the Green/yellow stripe ground wire for the coil has a weird pattern when I probe it to ground