 Fuel pump electrics issue |
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| cosm3os |
 Feb 1 2020, 02:57 PM
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#1
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Newbie  Group: Members Posts: 22 Joined: 26-December 19 From: Valparaiso, IN Member No.: 23,766 Region Association: None  |
Fuel pump only works when the relay is jumped. I've got no juice at the fuse (the rear-most of the two according to the manuals). I suspect that's why the relay has to be jumped. Where do I start tracing the problem? By the way, what size fuse should be in there--Haynes and 700 disagree?
Thanks, Kyle |
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| ctc911ctc |
Feb 1 2020, 03:50 PM
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#2
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Senior Member Group: Members Posts: 893 Joined: 9-June 18 From: boston Member No.: 22,206 Region Association: North East States 
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Try another relay, the Rear Most relay is for the Fan or if you have 4 relays the rear one is for the rear-window heater. swap one of these with the fuel pump relay - very common problem. One I just dealt with.
Next, is the logic power from the computer (D-jet controller) supplied when you turn the key?. you will need to look up the pin number, it is the plug at the back of the power distro board (one with the relays on it). Car year and engine please. QUOTE(cosm3os @ Feb 1 2020, 03:57 PM)  Fuel pump only works when the relay is jumped. I've got no juice at the fuse (the rear-most of the two according to the manuals). I suspect that's why the relay has to be jumped. Where do I start tracing the problem? By the way, what size fuse should be in there--Haynes and 700 disagree? Thanks, Kyle |
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| cosm3os |
Feb 1 2020, 03:52 PM
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#3
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Newbie Group: Members Posts: 22 Joined: 26-December 19 From: Valparaiso, IN Member No.: 23,766 Region Association: None |
QUOTE(ctc911ctc @ Feb 1 2020, 03:50 PM) Try another relay, the Rear Most relay is for the Fan or if you have 4 relays the rear one is for the rear-window heater. swap one of these with the fuel pump relay - very common problem. One I just dealt with. Next, is the logic power from the computer (D-jet controller) supplied when you turn the key?. you will need to look up the pin number, it is the plug at the back of the power distro board (one with the relays on it). Car year and engine please. QUOTE(cosm3os @ Feb 1 2020, 03:57 PM) Fuel pump only works when the relay is jumped. I've got no juice at the fuse (the rear-most of the two according to the manuals). I suspect that's why the relay has to be jumped. Where do I start tracing the problem? By the way, what size fuse should be in there--Haynes and 700 disagree? Thanks, Kyle C'mon! Gimme some credit! Just found an 11 page trouble shooting PDF. Gonna work through that. |
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| Mark Henry |
Feb 1 2020, 04:23 PM
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#4
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Ljet is a different relay, it's always best to state year, engine and FI (or carb) system.
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| cosm3os |
Feb 1 2020, 05:28 PM
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#5
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Newbie Group: Members Posts: 22 Joined: 26-December 19 From: Valparaiso, IN Member No.: 23,766 Region Association: None |
QUOTE(Mark Henry @ Feb 1 2020, 04:23 PM) Ljet is a different relay, it's always best to state year, engine and FI (or carb) system. 74 2.3L carb. I worked through that fantastic troubleshooter. Looks like the relay board is bad. |
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| ctc911ctc |
Feb 3 2020, 03:00 PM
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#6
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Senior Member Group: Members Posts: 893 Joined: 9-June 18 From: boston Member No.: 22,206 Region Association: North East States
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Prior to calling the board bad - I would thoroughly clean all of the connector contacts.
I went down the path you are on in the past. Unless the bottom is delaminating, (the rubber/plastic covering the bottom has hardened and fallen off and the copper traces are disconnected) the board should be in good shape. I have had 10 of these cars and never have had a bad board - though I have had quite a few ugly ones... QUOTE(cosm3os @ Feb 1 2020, 06:28 PM) QUOTE(Mark Henry @ Feb 1 2020, 04:23 PM) Ljet is a different relay, it's always best to state year, engine and FI (or carb) system. 74 2.3L carb. I worked through that fantastic troubleshooter. Looks like the relay board is bad. |
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