Gdetrailer wrote:
Wes Tausend wrote:
...
One more heat susceptible thing, not related to fuel, was the TFI
(Thick Film Ignition). Ford used it in the 80's and early 90's. I'm not sure if it was used on the 460 engines but it's highly probable.
The short story is I ran into this with a 1990 5.0 engine that worked fine previously, then sat around before it was installed in a hot-rod. The engine consistently ran poorly when hot and was even hard to start.
Usually the fix was to remove the module from it's mounting on the distributor and put new thermal paste between the module and a heat sink on the main distributor body itself. Apparently the thermal paste dried out from either time or inactive use.
Wes
From memory, if I remember correctly, there was two versions of the early TFI as it has been many yrs since I looked at these systems..
One version was the TFI was mounted directly to the distributor and the other version was a remote mounted version.
The distributor mounted version was typically used in cars and the remote mounted version was used on trucks.
I have worked on the distributor mounted version with frustrating results for a family member. Never ever got that engine to run correctly without it randomly stuttering to death at stop lights.. Changed every sensor, the distributor, coil, the TFI module twice, fuel pump, injectors and the ECM but yet the issue still persisted..
I did find there were some folks on the Internet that discovered part of the issue was grounding issues in the wiring harness, Ford doesn't use a central grounding point and many things are randomly grounded all over the vehicle. Grounding wires from various places in the wiring harness would corrode and fail causing all kinds of strange engine issues.. Family member sold the vehicle before I could try that.
I did briefly look at a pickup truck with poor idling, that is when I noticed on the trucks the TFI was mounted separate remotely from the distributor mounted to the wheel well liner, makes sense since a truck under heavy use generates considerably more heat than most autos..
Gdetrailer,
I believe the distributor problem was exceedingly common. The reasoning is the long story.
The hotrod was a Shelby sportscar replica. My buddy bought a finished car after seeing mine. His engine was giving him fits just like the OP here, especially in slow, hot parades. Gotten busy at work, my rig was still sitting unfinished and gathering dust, so I loaned him my unused distributor. Unfortunately my 'trial' distributor had exactly the same problem, although it had worked flawlessly in the Mustang it came from.
After pulling his hair out, my buddy finally discovered the distributor thermal paste problem (passed down from another hotrodder(s) who had also experienced the gremlin). From what I understand, it takes a special tool to remove the module from the distributor body, so he bought the tool along with some correct new thermal paste. That procedure fixed it right up for him, good as new to this day.
Some trivia...
I think he brought my defunct distributor back maybe a year later. I am not even sure where it is now. By then my employer had suddenly gotten busy and stayed that way for the next 15-20 years. It was a curse. They worked me 80 to 100+ hours a week, mostly out of town. I did little else but work and eventually lost hope in the car until it didn't matter. All I remember is working and sleeping for most of it. The long forlorn chassis project continues to gather dust up on a lift. It's a shame.
Wes
