 Fuel Pump Troubleshooting, I'm stumped |
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| ThinAir |
 Sep 17 2019, 07:12 PM
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Best friends  Group: Members Posts: 2,555 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region 
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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? |
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| rhodyguy |
Sep 18 2019, 12:58 PM
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,206 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
Can you use the carb jumper wire trick to power the pump for testing? It would run continuously when the key was turned on.
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Posts in this topic
ThinAir Fuel Pump Troubleshooting Sep 17 2019, 07:12 PM
TravisNeff I would also suspect the relay board. When you tu... Sep 17 2019, 07:26 PM Spoke You can isolate the fuel pump drive circuitry from... Sep 17 2019, 08:44 PM
ThinAir Thanks, Spoke. I'll give that a try in the mor... Sep 17 2019, 11:50 PM ThinAir Grounding pin III does indeed cause the pump to ru... Sep 18 2019, 12:53 PM ThinAir
Can you use the carb jumper wire trick to power t... Sep 18 2019, 01:06 PM SirAndy Can you use the carb jumper wire trick to power th... Sep 18 2019, 01:09 PM SirAndy Is your fuel pump fuse OK? (91) in the pic below.
... Sep 18 2019, 01:12 PM ThinAir
Is your fuel pump fuse OK? (91) in the pic below.... Sep 18 2019, 01:22 PM dr914@autoatlanta.com no all three cannot be bad and relay boards rarely... Sep 18 2019, 01:40 PM ThinAir It works again!
After reviewing the diagram, ... Sep 18 2019, 01:40 PM Spoke
It works again!...I'm thinking that I jus... Sep 18 2019, 07:25 PM ThinAir :driving: WooHoo!!!!
Just got ba... Sep 18 2019, 03:46 PM SirAndy Red Rock Classic 2019 - here we come!
Pack sp... Sep 18 2019, 04:52 PM jim_hoyland A spare pump is cheap insurance... :) Sep 18 2019, 04:33 PM |
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