Problem starting when it's wet out

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Feb 13, 2011 | 01:23 PM

Teamrope

Thread Starter

Mountain Pass

Joined: Feb 2011

Posts: 140

Likes: 2

From: Catheys Valley, CA

Problem starting when it's wet out

I've got 91 Bronco with a 351. Normally when I turn the key on the fuel pump cycles on for a second or two and then shuts off and it starts like it should.

When it's damp out the fuel pump cycles on, but doesn't shut off. When it does this you can crank as long as you like but it will not fire @ all.

I'm leaning towards the PCM, but a mechanic friend of mine that used to have a Bronco doesn't think thats it. The windshield does leak, and I know of other Ford trucks as new as 1999 that have funny issues with the PCM due to this.

Feb 13, 2011 | 04:50 PM

kumabronc

Junior User

Joined: Jun 2003

Posts: 56

Likes: 0

From: Austin

I had a similar issue with my '93. My negative battery cable had corrosion on the terminal. The corrosion wicked its way up the cable beneath the insulation. The resistance through the cable was way too high. Several hundred ohms if I remember correctly. On damp days the resistance went even higher.

Replaced the cable and the problem never resurfaced.

Feb 13, 2011 | 06:47 PM

FourXFord2

Elder User

Joined: Sep 2010

Posts: 667

Likes: 0

From: Small acerage in Nebraska

Maybe you could try packing the ECM connector with a dielectric grease. Dielectric because it's not supposed to conduct electricity very well, If moisture is getting in the connector and shorting it out, this should stop it temporarily.