I have a 1992 F150 with a 300-6 with 220K miles. A couple months ago, the computer smoked. I replaced it with a reman from Advance Auto Parts, and it started right up,,,,,,,,,,,, for a couple days. Now, every time it rains, the truck won't start. I tried using starting fluid, to see if it was a fuel issue, but it won't hit on that. I used dielectric grease on the connection, and put a little silicone around the cover around the computer, but it still won't start if it rains. Give it a few days to dry out, and it fires right up.

Any ideas????????

 

When its raining and won't start spray the coil, coil wire the cap and spark plug wires down with WD-40.

If it fires up after doing so? replace the spark plug wire set.

 

I had a similar issue a year or so ago and I replaced the dizzy cap and it fixed my problem.

 

I tried spraying wire dryer on the cap and wires, but it did'nt help.
I replaced the cap, rotor, and wires a couple years ago. The truck isn't driven on the road now, since I need a one ton truck for work, but it is used on the farm. It has never failed me til now.

Is it a coincidence that it only started doing this after I replaced the computer? I did noticed that the metal tray that holds the computer was rusty, indicating a wet condition at some time. I suspect if the computer itself was getting wet though, it would fry. As soon as we have a couple dry days, it fires right up like it always has.

 

Check your little rubber vent cap on your distributor.

My friends van with a 300 had that problem, anytime it rained, or was really humid outside, it wouldn't start.

I went over, took the doghouse off, and removed the dizzy, and found it was moist inside. So I took that little vent cap off, blew in it, and crap came flying out, it was clogged.


No problem after that.

 

Not driven on road is hard on one, never gets any real air flow and more often then not wouldn't make it to full operating temp. And or not used or left to run long enough at any one time for the engines heat to dry things out under hood.

Couple years might be all it take kill a new set of wires under those conditions.

Did you take the cap off make sure its dry inside?

And the computer pull it out and take the cover off, see if its damp inside or signs it has been.

 

Changed cap, rotor, and wires,, nothing changed.

I did just notice that I can hear the fuel pump run and keep running, and it won't start. A couple times when I turned on the key, it ran about 4 seconds, then a click, then the pump was silent. It fired right up each time that happened.

Ideas??

 

That is a pretty good indication the computer is the problem, computer failing to stop pump after a second or two after key has turned to the "run" position, engine not running.

If it runs as long as the key is on motor not running, the computer is toast.

Usually accompanying that condition, computer failing to fire/open the injectors.

 

Dist. cap is cracked. I bought 2 vehicles because of this. Changed caps and always fixed the problem.

 

Changed cap, rotor, and wires yesterday,,, no change.

 

Installed a new computer today, and it fired right up. We are suppose to have heavy rains tonight, so we will see what happens. Hope this took care of it.

thanks,,,,,

 

Rained hard for the past 12 hours or so. Truck fired right up. First time that has happened in the past couple months. Hopefully the computer fixed it. Will check back in in a few days.

Thanks everyone!