I have been having a lot of trouble with my '93 F150, 5.0, 2 wheel drive, AOD Trans, running rough. I have fixed codes and even threw a few parts at it. So i took it to Ford. They had it 3 weeks and $400 later and now it won't even start. If it does start it will run for a few minutes and die. No Spark. Ford was sure it was the Ignition Control Mod. Even put in 2 different ones. I just spent the better part of the afternoon running ignition tests from my Haynes manual. The conclusion, 3 different ways, is the Ignition control Mod.

All tests passed except:

Ignition problem symptoms
Refer to illustration 7.3
2) Unplug the electrical connector from the ignition control module
(ICM). Inspect It for dirt, corrosion and damage, then plug it back in.

3) Attach a 12 volt DC test light between the coil TACH terminal and
a good engine ground (see illustratlon). Crank the engine and observe
the test light.
4) Remove the test light.

Result is:
Symptom2
6) If light comes on brightly but doesn't flash. the problem is in the
primary circuit (open from TACH to module) or ignition control module
(stuck open transistor). Check primary circuit harness continuity from
TACH to Ignition module first (see Step 16).

My question is what can be burning out these modules??

 

Did you test the PIP module in the distributor? This is where the timing signal that drives everything originates.

 

Yes, I tested the pip connector, power in, Signal in, and signal out. All passed. It is a new dizzy. I had replaced it because the bearings were gone and again, under warranty, because Ford said it was the problem.

 

Your truck should have a grey ICM, does it?

 

The original was gray. The first replacement was gray and the 2nd replacement is black. The grey one is in now.

 

What difference does the color make? There are about a dozen choices on Rock Auto's site.

 

Excellent reading here: Ford TFI modules: Gray or Black?

 

That was educational. I'll show it to Ford tech. I got them to order another ICM. When I took it off I found it didn't have any heat sink past (di-electric grease) on the back!! I hope that is the reason it burned out!!!!

 

In bold above is a huge contributor to premature ICM failure. The other is using dielectric grease as thermal paste between the ICM and heat sink. You need real heat sink compound. There is a difference between dielectric grease and heat sink compound.

Be aware most Ford part manuals list the wrong ICM for this vintage truck. You need a gray colored Push-Start version. We go through this Chinese fire-drill every week or so.

 

I have dielectric compound. Just thought it was the same because that is what the manual calls for.

 

One last question. When asked "With or with out electronic engine control IV" what is the answer??

 

With Electronic Engine Control IV (EEC-IV)

This might help: FSB Forums - View Single Post - Ford TFI Ignition Control Modules


Complete thread here: http://www.fullsizebronco.com/forum/showthread.php?t=183668

 

Heat Sink Compound (aka thermal paste) is designed to transfer heat whereas dielectric grease is designed to be an insulator. While anything is better than nothing I would not substitute one for the other.

 

A Radio Shack or similar electronics store will have proper heatsink compound.