Difficult starting & running after it rains

[penzfan11]

I just bought a 91 Bronco, 5.8L V8, automatic trans. (my 1st Bronco).

I just gave it a tune-up with plugs, wires, dist. cap, rotor and fuel filter.

I'm still having problems with starting it and keeping it running after it rains. After a rain (or heavy fog) it will start with the first turn of the key, but after a few seconds it starts to spit and sputter, then stall. If I put my foot in the gas and hold it at 2500-3000rpm, it will still spit and sputter and eventually stall. After it stalls, it usually takes a few cranks to get it started again, and the same thing happens. Sometimes I can get it to eventually stay running, but sometimes I have to wait for the weather to change and everything under the hood to dry up. When it's not raining, it runs fine.

I just bought this last month and haven't been able to enjoy it yet because I've been messing around with getting it to run right.

Any help would be greatly appreciated.

Brian

 

[BroncoJoe19]

My guess is that the moisture in the air, or condensation on your wires is allowing the spark to conduct to a ground and not force it to jump the gap at all of your plugs.

Make sure that all of your wires are well seated onto the plugs, and into the cap. Also into the coil.

If that does not do it. Then see if you can make additional observances, and see if it is actually weather related. Let us know either way.

 

[GDare]

Wow! I am having the EXACT same problem. I just bought a 91 Bronco, 5.8 V8 and am having the same problem. Just replaced the spark plugs, fuel filter, air filter, plug wires, distributor cap, rotter, etc.

The truck wont start, have tested the battery and tried a different ignition coil... still nothing. I don't know if the cold/rainy weather has anything to do with it... but it has been raining off and on since i bought it, and that actually seems to make a lot of sense. One morning it wouldn't start, i left the hood open for a bit and after the engine had dried and gotten some sun it ran fine... seriously doubt the moisture is the problem though.

Pretty sure there's some faulty wire, it seems the coil is not getting enough power to the coil. Anyone have any ideas? Any theories about moisture?

Did you ever figure it out penzfan?

 

[BroncoJoe19]

Gdare,

You might try this.

one a clear day, when she starts, try spraying some water on the wires and see if you can see any arching of the spark. Does it run rough after the spraying? Does it not start?

Pull diagnostic trouble codes from your computer. Here's how.

How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway

Howto Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more

Make sure all the plug wires are well seated.

 

[penzfan11]

I've checked the plug wires and they are seated. I also tried spraying water on the coil and plug wires when everything was dry. I didn't see any sparks and there were no idle problems. I waited 15 minutes and restarted it, no problems.

After I get it running it drives fine. My check engine light never comes on and Auto Zone told me their scanner only gets codes if the light comes on and I'd have to go to a mechanic to get the "stored" codes. I think I'll try the wire first and see if I can get any codes myself.

Thanks for that great tip.

I'm sorry to hear someone els is have the same problem, but it's nice to know I'm not the only one. Hopefully, one of us can figure this out.

 

[Maddog]

Did you see any condensation at all in the cap? Try using a compressor to blow it out and check for cracks or the rubber grommet that might seal the distributor to the cap..

Did you try the water spray trick in a darkened environment? You may not see the sparking during the day or under bright lights..

 

[penzfan11]

Sorry I've been away a while. The problem just stopped and I don't know why.

Now I'm having idle/stalling issues when it's warm. I drove to work today and while drive about 30mph, the idle started bouncing like it wanted to stall. A few days ago it did the same thing and when I stopped it stalled. I started it, put it in gear, tried to drive and it stalled. I had to rev the engine and drop it in gear to get going, but it still had erratic RPM's all the way home. The next day it was ok, the day after it did it again.

I cannot figure this thing out at all.