Fuel Pump Troubleshooting, I'm stumped Options

[ThinAir]

Trying to get my car on the road for Red Rock Classic. It's not looking good.

I had an intermittent problem with the fuel pump not running, which at the moment seems to be no longer intermittent. I've successfully tested the pump by connecting it to a battery charger.

I've followed the steps in the two fuel pump diagnostic documents at Jeff Bowlsby's site (http://bowlsby.net/914/Classic/zTN_FI_FPChecklist.pdf and http://bowlsby.net/914/Classic/zTN_FI_FPChecklist2.pdf). They both fail at the point where it says I should wrap a wire around pin 87 and reinsert the relay. I get no power on the wire. Following the steps in the Brad Anders document, I don't have 12V on pin 86 and when I test pin 8 on the plug I have power so that means I have a faulty relay board trace.

My board was rebuilt last year by a member here who has a great reputation so I don't have any reason to doubt my relay board. I have also tested with 2 other relay boards as well as multiple relays - all with the same result.

It just doesn't make sense to me that 3 boards could all have the same issue. I'm stumped. Can anyone provide some additional things to check?

[ThinAir]

It works again!

After reviewing the diagram, I decided to check continuity between pin 10 and pin 86 on the Power Supply relay (75). It checked out.

At this point I plugged in all the relays and the 14 pin connector and tried it again. Much to my surprise, the pump ran like it was supposed to and the car started and ran just fine.

I'm thinking that I just had a loose connection all along. I'm suspecting that it was something in the 14 pin connector, but I really don't know how to pin that down.

Thanks for all the helpful hints. Time to drive it and see if it continues to behave. If it does, then it will be at Red Rocks this weekend!

[Spoke]

It works again!...I'm thinking that I just had a loose connection all along.

(IMG:style_emoticons/default/beerchug.gif)

Good to hear. The unplug-then-plug on connectors is a very common fix with older electrical equipment. Connector contacts oxidize with age and moisture and the unplug-then-plug scrapes the oxidation away to make better contact.

It is a warning sign that some preventative maintenance on the plugs and sockets is warranted. Get some kind of small wire brush and clean the contact surfaces of the plugs and sockets for robust connection.