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.
Just off the top of my head I'm thinking 2 or 3 possibilities...
-Distributor cap condensation? Possibly the gasket is worn allowing moisture in?
-Loose connection on the firewall or fenders allowing the rain running down it to short out?
-If none of the above, I recommend a move to somewhere it never rains?
My F150 - 1996 F150 XL 2WD 4.9L (300ci) I6, E4OD Trans, 3.08 Rear, 260,000 miles and runnin strong.
Mods to date - K&N stock replacement air filter; (4) Ultra "Rogue" 16X8 rims 3.74 BS; (4) Grabber AT2 31X10.50X16 tires; Black Euro LED head and bumper lights.
Other Vehicles: 2005 Crown Vic, 1996 Nissan Maxima (for the kids)
Last edited by Preston121068; 12-15-2011 at 06:08 PM.
I seem to remember somebody else having a problem with this. Have you searched the forums at all?
Explain a little more... If you go to the store and it rains as you are driving there, shut off the truck to go inside and then come out, will it start then? Or only after its been sitting for awhile, say it rains over night and try and start it in the morning...
I sprayed wire dryer on the cap and wires, but it didn't help. I also sprayed it on all electrical connections under the hood. Nothing.
The cowl seal is in great shape, but falls short of where the main plug and the computer plug is, so water flows down across them both. I applied a heavy dose of electric grease to both plugs on a dry day when is was running good. Rained today,,, won't start.
The truck isn't driven on the road now, but is used on the farm alot. On a dry day, it runs great. If I get up and it has rained overnight, it won't start. The cap and wires only have about 15K miles on them.
It just seems strange that this problem started when I changed the computer. Never had a problem before that. The computer is under warranty, so I thought I might get it exchanged out to see if the problem is in it. I could see when I changed it, that the metal tray it slides in had rust on it, so I know it was wet at one time or other. I expect if the computer was getting wet, it would fry when I tried to start it.