I have a 91' F-150 5.0L 4x4. In my last post I could not get the truck to start. So I replaced the fuel filter, distributor cap and rotor, ignition module, and finally the whole distributor. replacing the distributor fixed it. I got it running and during the warm-up time for setting the timing it just dies. I initially set number one cylinder at TDC and I got the rotor in the dist. dead on the #1 plug wire. This is where I started. I got the truck to start by making a very very small turn on the distributor in the retarded direction. I have the spout pulled and as I get ready to check the timing marks it dies. So It has not run long enough after the warm-up for me the check the timing. Do I need to start over or am I missing something. Thanks in advance. Oh it idles by itself at about 800rpm before cutting off.

 

You may have a problem with IAC valve or a vaccum leak some place.

 

I found a broken vaccum line coming off the "juice can". I made a repair to it. The truck runs smoooth until it warms up then cuts off and will not restart. I let it cool down for a couple hours and tried it again with the same results.

 

I would begin by testing the TFI module and the ignition coil when the truck won't run. The simplest way to do this is by checking for spark while cranking when the truck will not start.

 

Sounds like a bad TFI to me too. They are a common Ford problem and are definitely heat sensative. I take it the distributor swapped was used? Otherwise, would be warranted. Only thing otherwise that I can think of is that you are way retarded (timing) but if you were on TDC 1 and it sounds like you were, you shouldn't be (maybe a tooth off?) but heat has nothing to do with that so still lean towards bad TFI. Making headway though, good job. Rest should be easy compared to hair lost figuring it out. Oh, just thought of year...think on trucks they are still dist mounted (Mustangs went to remote mounted after 94).

 

Im sorry i dont know all the acronyms yet....TFI???

 

oh yeah one more thing... what exactly does the SPOUT connection do. can i run the truck without it permanently.

 

TFI = Thick Film Integrated ignition module. You 91 should have the TFI module mounted to the distributor, and it is the part of the distributor that the wiring harness plugs into. Were you able to get the truck running by pulling the SPOUT connector? When the SPOUT is removed, the timing signal goes straight from the distributor to the coil, basically, bypassing the computer controlled advance, which goes back through the TFI module on its way to the coil.

 

I have already replaced the TFI i just refered to it as the ignition module. I dont think the original was bad. The truck would not start when i pulled the Spout connector. I think what i am going to do is go back and check everything at TDC on #1 cylinder and then try to start it without the Spout. If i can get it to stay running I will go from there. What does everyone think?

 

Here is what I think. You replaced the distributor, with I assume a rebuilt distributor.(I'm not sure if you could even buy a NEW distributor). The rebuilt distributors have an absolutely terrible reputation, more often than not they seem to be defective.(I learned that from reading forums like this). I think the PIP in your rebuilt distributor is going dead when it warms up and then comes back alive when it cools down. Bottom line: I think you got a bad replacement distributor. You asked WHAT DOES EVERYONE THINK, that's my answer.

 

Put It Top Dead Center Advance It About 10*and See What Happens, As Soon As The Truck Starts Disconnect The Spout.