96 grand Cherokee v8
Jeer won't start after rain. Cranks but no spark a least I think. I sprayed ether in carb, no fire. It ran fine 2 days ago before we got rain. I did change the cmu a month ago because it did the same thing. So not so sure that was the issue.
Thanks
Thanks
Senior Member
Joined: Dec 2012
Posts: 638
Likes: 16
From: Midwest
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0L
CMU? any chance you mean ECU or PCM? when was the last time the vehicle had a full ignition tune-up?
Also your jeep is fuel injected not a carb, I think you meant throttle body.
Also your jeep is fuel injected not a carb, I think you meant throttle body.
Senior Member
Joined: Dec 2012
Posts: 638
Likes: 16
From: Midwest
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0L
if you have worn ignition componentes, ie wires, cap, rotor. when they get any moisture on them they will cause the spark to arc to ground before it reaches the plugs. this can be tested by misting some water over the wires and cap while its running to see if if it makes a difference.
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 740
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Spray the INSIDE of the cap with some carb cleaner, BUT make sure it's completely evaporated before you put it back on. This will remove any carbon trails and oil film that tends to collect moisture.
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I was going to do that. The ol' girl started this morning, we haven't had any rain for a couple of days. Think I'll spend the $ and put cap and wires on. I'm sure it's been forever since they've been replaced. Hopefully will have time this weekend. Thanks for the help.


