1992 F150 straight 6 odd no start issue

[tri again]

I've put 10,000 miles on this but never have trusted it. 160K miles total.

I can start it 10-20 times on the farm, run it hot / cold and all is well.

Last trip to town, 5 min away, post office stop, wouldn't start.
Pulled the coil wire out of the dist cap, checked for spark and it started.
Happened again today.

In the olden days with oscilliscopes for engines (showing my age and ignorance)
if you pull a wire off a spark plug, it can double the voltage to the plug, same with the coil.
It is so darned intermittent and sporadic, it's very hard to test.

..so I'm thinking, by pulling the coil wire back and make it jump a bigger gap, it may convince the coil to
come to it's senses and work for a while.

OR I'm completely outta my mind.
Last summer, it would not start when the resting, ambient air temp was over 90 degrees F, but if I ran it in traffic, hot, it was never a problem.

new plugs, wires, cap, rotor, ignition control module, btw.

Maybe it's just time to start replacing parts one at a time and just accumulate
"known working spares".

With all the fords around, I can't be the only one with this prob.
NO codes, no check engine lite, runs GREAT, starts instantly and
will easily outrun a car from a dead stop with a full load of firewood.

Thanks for listening

[kebby28]

Ive owned a ton of these f150 with the straight 6. Bullet proof motor. The only thing that goes wrong is the two relays by the air box. One is for ignition and the other is fuel pump. You should always have a extra set in the glove box. I think they run around $20 each. If these relays are not working then chase the ground wire that runs on the top front of the radiator as there is a ware spot.

[slashfan7964]

Go back to basics. It takes air, fuel and spark to run. Make sure you have a good amount of all three haha. Sounds like the coil might be going though since you said its sporadic.


I agree the 300 I6 is a bullet proof engine. I had one before I did a double V8 conversion.

[tri again]

I think I'll just go get a coil and some relays.
Funky truck but certainly worth 100$ gamble.

I forgot about those relays. Have heard they can actually freeze with condensation
and bad connections under the fuse box.

Just not sure I trust NAPA electrics necessarily.
I also think I'm one of the few who is still Pi*&ed when it DOES start 'cause I can't check anything.

Thanks a lot, you guys.

[kebby28]

Yeah I got pi*sed once on a rainy day and smacked one of the relays with the but end of a screwdriver and off I went :lol: