Weird things when wet

[truckermark]

Ok did some digging no luck.
Truck is an early 99 7.3 auto trans.
Every time it rains it will randomly cut out and die for a second but never fully die. It will do it randomly. I thought it was my cps getting interference from the wipers.
How ever yesterday it was sprinkling out. And twice. The the truck bogged down for a second but never died. The water in fuel light came on along with the WTS. But went away. I didn't have my wipers on. Truck is running good. It doesn't
like the rain.

PS I haven't noticed the water in fuel light coming on briefly before yesterday

 

[greenskeeper]

check IDM for water

 

[79jasper]

I would go ahead and make sure the fuel heater is unplugged.

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[truckermark]

check IDM for water

Will do check IDM tomorow.

I would go ahead and make sure the fuel heater is unplugged.

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As far as the fuel heater being unpluged. Where is this located. And would this be affected by wet conditions?

 

[79jasper]

It's on the side of the fuel filter bowl. It runs off the same fuse as the pcm. #22 in the under hood fuse box, iirc.

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[truckermark]

It's on the side of the fuel filter bowl. It runs off the same fuse as the pcm. #22 in the under hood fuse box, iirc.

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So it's possible that sensor is affected by moisture cuasing pcm to cut out?

 

[Kevin 007]

I second the IDM inside the drivers fender. See if its getting road spray up in there. Check the main large square wiring harness plug on the drivers side of the engine also. Underhood fuse box area, and all grounds, make sure all grounds are grounding well.

 

[lotzagoodstuff]

+1 on the IDM, lots of documented cases where you can hear the water sloshing around inside of them.

I would also check the body ground. It sounds like it might not be a bad idea to add an additional body ground on any 7.3 PSD.

Lastly, have you tried using your wiper motor when it's not raining? I seem to remember some issue with some crank position sensors getting interference from the wiper motor. It makes you think it's a rain issue, but in reality it happens when you use the wipers.

Good luck, intermittent problems are always the hardest ones to fix.

 

[truckermark]

I second the IDM inside the drivers fender. See if its getting road spray up in there. Check the main large square wiring harness plug on the drivers side of the engine also. Underhood fuse box area, and all grounds, make sure all grounds are grounding well.

+1 on the IDM, lots of documented cases where you can hear the water sloshing around inside of them.

I would also check the body ground. It sounds like it might not be a bad idea to add an additional body ground on any 7.3 PSD.

Lastly, have you tried using your wiper motor when it's not raining? I seem to remember some issue with some crank position sensors getting interference from the wiper motor. It makes you think it's a rain issue, but in reality it happens when you use the wipers.

Good luck, intermittent problems are always the hardest ones to fix.

Will be testing into idm shortly. And yes I have tried running the wipers when dry. (Found that idea on here! Love this site) still no issuel. As an experiment I drove through a huge puddle. At least 8 inches deep. At 45mph. And in that moment it did not affect truck at all. It just kinda happens when it happens. But only when wet outside

 

[lotzagoodstuff]

It just kinda happens when it happens. But only when wet outside

Smells like a grounding issue......

 

[truckermark]

ok guys. Got my inner fender plastic off and pulled out the idm. Didnt find any water. but the button plug thing that is in the pic was found in the little tabs that it is sitting on. so i can see the circuit board. Looks like mist could get in there. Anyone re seal these up before? also my wiring harness looks like its seen better days. Does die electric grease play nice with these electronics? or is it better left untouched? sorry if i open up an entire debate here lol

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[79jasper]

Did you pull the cover apart to the idm? You need to actually look inside.

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[truckermark]

Did you pull the cover apart to the idm? You need to actually look inside.

No I did not. Just kinda tiped it to see if water came out. Will go tale the cover off. What purpose does the round plug serve?

 

[truckermark]

ok i dont think i see any water damage. Going to re seal plug on. it has for holes in it. is it meant for the idm to breathe

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[79jasper]

Pretty sure it's supposed to be plugged.

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