My 1994 F-150 4X4, 5.8 auto, wouldn't start after it rained. It would crank over but acted as if there was either no fuel or no spark...hence the no starting. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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There is plenty of spark from the coil.<o></o>
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The fuel pump would run with the key in the start/run position but would not shut off once the system was primed/pressurized.<o></o>
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I replaced the pressure regulator but it did not help.<o></o>
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Two dry days later it starts fine<o></o>
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Any ideas?<o></o>

 

Distributor cap may not be sealed and getting moisture in it......Pull it off in the wet conditions. I have had this happen when power washing my engine down.

The inside of the cap will have a coating of water in it causing the internal distrobution of spark to throw crazy inside.

The MSD cap is an awsome deal . they are much more durable and last really, really long with stock engines.
a factory cap here is @ $10 and good for about 4 months it seems , the MSD cost me $35 dollars years ago

 

Thank you but I already have an MSD cap, rotor, wires, coil, and MSD 6 box. The truck acted as if there was no spark or fuel being supplied to the engine. It just cranked over. I have plenty of spark from the coil. The fuel pump continued to run leading me to beleive the pressure regulator was falulty but I replaced it with no change. After two dry days the fuell pump now runs for a few seconds then shuts off after priming/pressurizing the system and the engine runs fine. Thank you for your response.

 

I've had the same problem - with two fords of mine. Spray all that stuff down with the wire dryer spray. Ford seems to be synonymous with moisture issues

 

Wire dryer spray....never heard of it. I see if I can find some and thanks

 

Check your grounds...
I had the same common issues with my truck like, weird gauge readings, dim lights, and some charging issues.
And 1 day I went from bumper to bumper cleaning every ground wire I could find or trace down - now my electrical system is perfect. Maybe I'm lucky it was just that, but some of them were pretty bad... LOL

 

Same thing happens to my flareside in the rain or a moist morning, I havent quite figured it out but I'll try some of that stuff out

 

I have a 1992 flareside 5.8 that did same thing.It is related to the fuel pump
issue of not shutting off with key on after 2 to 3 seconds.The problem is due to a dirt fuel filter.When changing get replacement filter clips if they are the
ones internal to the fuel line(autozone)cheap couple of bucks.Also have someone help you purge the fuel line from pump to filter before installing new
filter.Just use a jug to catch fuel when key is turned on.RUN TILL FUEL RUNS CLEAN should only need about a pint to clear line.

 

The truck seems to be running fine but I'll replace the filter and purge the lines. Thank you for the tip.

 

STP makes WIRE DRYER... I sock my distriputer cap and wires down with that stuff... it seems to seal out the condensation that builds up around th cap.

 

Well, I haven't found the "smoking gun" since it has been pretty dry for the last few days and the truck has been running pretty good. I'll keep a can of wire dryer behind the seat...just in case. Again, thanks for all the suggestions. I'll chime back in if I finaly figure this out or it happens again. I understand we are suppose to get rain in the next couple of days.

 

jmorris47 where do you call home? Sounds like you're in my neck of the woods, Louisville KY - I don't think we can go 3 days without rain!!! I'M TIRED OF IT!

 

I have the exact same problem and it turns out I had moisture getting in the gap at the back of the hood. There's a seal that's supposed to be there that let water run in and all over the back of my engine including the ignition coil and a bunch of wiring harnesses. Check to make sure that's not happening.

Josh

 

I agree with checking the ground wires make sure they are all good and not getting moisture on them.

 

Well its been almost two weeks and we've had a couple of good rain storms here in Crestivew Florida but the truck has run fine. I have wrapped everything I can fine with new electrical tape and so far the truck runs fine. I really can't explain what happned but I'll be back if I find something or it happens again. Thanks again for all the suggestions.