Ok, here's the deal. I just swapped a 351 into my 87 F150 that originally had a 302. Swap went without a hitch, and the truck ran great for one day. I had the truck idling in the driveway, and it just quit. No sputter, no cough, just quit...as if I had turned off the ignition. I immediatly assumed it was ignintion, so I grabbed my test light and had my dad crank the engine while I checked the coil leads. I've got power to both sides of the coil with the key on, so the ignition switch is good, however...when you crank the engine, the tan wire is suppossed to give a pulse signal, right? Well it didn't. Both the dizzy and the TFI module were new, but I had heard that they like to die, so I took them back to the parts store to be tested. Sure enough, TFI was bad. Got another one for free and put it all back on the truck. Cranked right up and ran great for about 5 mins. Dead again. Same symptoms. Did I just get lucky enough to buy two faulty TFI modules, or is there something that could be killing them? HELP PLEASE!!!

 

Are you installing the TFI modules or are they mounted on the distributor from the parts store? The module has to be installed with dielectric grease between it and the distributor body, or will overheat and die in short order.

 

Not sure on a 1987 but a 1986 had a 1.1 ohm resister at the ignition switch for run but not for start.
The 1988 F series did not have the 1.1 ohm resister but the E-series had it still in 1989.
Without the 1.1 ohm resister the Ignition Coil would go bad and maybe a bad or wrong coil would take out the TFI Module.
Also make sure you put the required White Silicone Grease (not dielectric grease) on the TFI Module before you put it on or it will go bad fast.

One side note always buy the TFI Modules from Ford or a salvage yard and not from an auto parts store.

 

I installed it, and made sure to smear that crap all over the back of the TFI. The previous module burned up because it did not have the grease....but it lasted a whole lot longer than this one did. Seriously, 5 minutes from a cold start. Thanks for the reply!

 

Subford, the ignition switch and coil are the original parts that came with the truck, and they have been running just fine with the 302. The only different electronics introduced into the system have been the '89 351 distributor and TFI module. Maybe I should take the TFI module off of the 302 dizzy?? Shouldn't make a difference I wouldn't think, but I've seen stranger things! Thanks for the reply!

 

Use the TFI from the 87, they are different systems.

Also make sure you put the required White Silicone Grease (not dielectric grease) on the TFI Module before you put it on.

 

So since I've been using a TFI module from an 89, what have I done to the rest of my electrical system? I have an 89 5.8 computer, will it work with an 87 TFI module?

 

The Computer will work OK, as that is not where the difference is.

But you will get a false fuel system error with the 89 computer as you are missing a wire from the fuel pump relay.

 

Sorry for all the questions, but will the 87 TFI module work with the 89 dizzy? Since EFI wasn't offered on the 351 in 87, I can't get a dizzy for that year. I never thought that the TFI modules themselves would have been different. Thanks!

 

Apparently that false fuel system error doesn't trip the Check Engine Light, because so far, I have had no CEL's. Of course, I'm pretty sure this truck will run on any computer...the computer I pulled out said "3.0L Taurus/Sable only". It was driving a 302.

 

Do you happen to know the Ford engineering number from that computer? it will be something like: E6DF-12A650-AA

Several years ago, Ford recalled 5 MILLION of those crappy dizzy mounted ignition modules. The original part number was E43Z-12A297-A. Before the recall, millions of owners replaced those modules out of their own pockets. I sold 100's over the years. The modules have Ford engineering numbers of: E3EF-12A297-A1A, or E3EF-12A297-A2A.

 

Subford, since I'm using the 89 computer and the 89 dizzy, should I not use the 89 TFI module? Seems to me that since the TFI talks to both of those systems, I should match the year models. True?

 

NumberDummy, no I don't know that number off the top of my head. I can get it later though. The recall wasn't on the computer though, just the TFI module, right?

 

The 1980/89 Ford Light Truck Parts Catalog (Section 120; page 17) says: 1984/89 E-F150/350 and U150 use E43Z-12A297-A Ignition Module (Motorcraft DY-425).

This is the only dizzy mounted module listed for those models and years.

Recall was for the module, and maybe the stator too (pickup coil in dizzy).

The part number is still valid.

 

The 87 would have the "push-start" Ignition System "A" and the 89 may have the "Computer Controlled Dwell" (CCD) System "E".
I have not studied all seven of these systems in detail so I do not know where all the differences are in the systems.

It is also possible that the pick-up unit in the Distributor is different and taking out the Modules.

If you like I can post diagrams of all seven TFI systems but some may be for cars.