 No power to fuel pump, seems to be a common problem around here |
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| warrenoliver |
 May 24 2013, 10:04 PM
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Member  Group: Members Posts: 363 Joined: 11-November 06 From: McFarland, Wisconsin Member No.: 7,199 Region Association: Upper MidWest  |
Car stalled on me this morning. When I tried to restart, the fuel pump would not turn on so no luck with the start. Towed it home and checked it out. It is a 73 2.0 with FI.
The pump runs when I jumper directly to the battery. I have continuity from pump connector to the #13 pin on the relay board. If I jumper from the fuse to the #13 pin, the pump comes on. The fuse is good. I have replaced the main power relay and the fuel pump relay with known good ones. With the ignition on, when I remove and reseat the main power relay, I can feel the relay click but I do not hear the injectors click nor do I hear the fuel pump start (I got this test from Dr. 914's Tech Tips). On the fuel pump relay socket, I have power at the 30 pin and also the 85 pin. When I jumper to the 87, it does not turn on the fuel pump. I don't know if it is related, but I have the same problem with the heater blower relay also. I jumpered 30 to 87 and I do not have power. I am not sure but I think the car died when I had the heater blower running. I'm stumped. What do I check next? |
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| Tom |
May 25 2013, 03:46 AM
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#2
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Advanced Member Group: Members Posts: 2,139 Joined: 21-August 05 From: Port Orchard, WA 98367 Member No.: 4,626 Region Association: None |
Jumpering pin 87 of the fuel pump relay is the same as jumpering pin 13 of the 14 pin connector to power. You say pin 13 to power makes the fuel pump work. Try jumpering the fuse to pin 87 of FP relay. Pump should come on. If not, you have a problem with the fuel pump relay socket to relay board traces. Try cleaning the fuel pump socket with a small wire brush or rolled up fine sandpaper.
Here is a different pic of the relay board. Tom Attached thumbnail(s) 
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| warrenoliver |
May 25 2013, 07:17 AM
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#3
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Member Group: Members Posts: 363 Joined: 11-November 06 From: McFarland, Wisconsin Member No.: 7,199 Region Association: Upper MidWest |
Tom,
When I jumper from the fuse to 87 of the fuel pump relay, the pump comes on. That really makes no sense to me since the 30 pin for that relay also has 12V but when i jumper from 30 to 87 - no joy. What gives? QUOTE(Tom @ May 25 2013, 04:46 AM)  Jumpering pin 87 of the fuel pump relay is the same as jumpering pin 13 of the 14 pin connector to power. You say pin 13 to power makes the fuel pump work. Try jumpering the fuse to pin 87 of FP relay. Pump should come on. If not, you have a problem with the fuel pump relay socket to relay board traces. Try cleaning the fuel pump socket with a small wire brush or rolled up fine sandpaper. Here is a different pic of the relay board. Tom |
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| warrenoliver |
May 25 2013, 08:00 AM
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#4
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Member Group: Members Posts: 363 Joined: 11-November 06 From: McFarland, Wisconsin Member No.: 7,199 Region Association: Upper MidWest |
I tested the heater fan circuit also. The fan runs when I jumper from the fuse to the 87 pin. It does not run when I jumper from the heater fan 30 pin to 87. Both the heater fan blower and the fuel pump relays get their power from the power supply relay (I think), but it still doesn't make sense why I can't get either one to turn on from the 30 pin of their respective relay.
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| warrenoliver |
May 25 2013, 08:37 AM
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#5
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Member Group: Members Posts: 363 Joined: 11-November 06 From: McFarland, Wisconsin Member No.: 7,199 Region Association: Upper MidWest |
I spread the pins on the relays and cleaned the contacts. When I jumper from the 30 pin of the power relay to the 87 pin of the fuel pump relay, the pump runs. Seems to be something between those two relays.
I don't really know where the white wires in the molex connector go but I assume they go to the ECU. I looked at the ECU and it looks like the wiring harness is hardwired into the ECU so I don't know if those wires go into it. When I ground pin III on the relay board, the pump does not turn on. I am stumped. I have an AX tomorrow that I would like to go to so I hope someone can help. |
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Posts in this topic
warrenoliver No power to fuel pump May 24 2013, 10:04 PM
Dave_Darling Both the heater fan blower and the fuel pump relay... May 25 2013, 08:45 AM warrenoliver Thanks Dave,
The relays are good. When i have the... May 25 2013, 09:37 AM Dave_Darling
When i have the power supply relay in, and the ke... May 26 2013, 11:26 AM
Jon H. Do you still hear the clicking coming from the TPS... May 25 2013, 04:20 AM Cap'n Krusty Install the 2 headlight motor relays in the FI con... May 25 2013, 07:36 AM warrenoliver I tried that previously but I just tried it again ... May 25 2013, 09:23 AM 76-914 . Here ya go http://members.rennlist.com/... May 25 2013, 08:09 AM warrenoliver Thanks for the Anders troubleshooting tips. When ... May 25 2013, 09:43 AM Bob L.
Thanks for the Anders troubleshooting tips. When... May 25 2013, 10:26 AM warrenoliver OMG, thanks Dave for the pictures. Without those,... May 25 2013, 12:17 PM Bob L.
OMG, thanks Dave for the pictures. Without those... May 25 2013, 12:50 PM warrenoliver Oops, sorry! Thanks Bob.
May 25 2013, 02:52 PM Tom Warren,
Sorry to not answer back sooner. I have... May 25 2013, 03:39 PM warrenoliver Tom,
I think you may be right but I just don... May 25 2013, 04:42 PM Tom Warren,
From what you have said, it doesn't... May 25 2013, 04:59 PM warrenoliver Tom,
I unplugged the AAR and it didn't help.
... May 25 2013, 07:00 PM Jon H. Don't forget, he is also not hearing the injec... May 25 2013, 05:22 PM warrenoliver I can hear clicking when I reseat the relays but I... May 25 2013, 06:42 PM Jon H.
I can hear clicking when I reseat the relays but ... May 25 2013, 07:02 PM warrenoliver Yes, when I jumper from the fuse to the 86 socket ... May 25 2013, 07:21 PM Jon H.
Yes, when I jumper from the fuse to the 86 socket... May 25 2013, 07:52 PM warrenoliver Thanks for all your help guys. Anyone know where I... May 25 2013, 07:55 PM Jon H.
Thanks for all your help guys. Anyone know where ... May 26 2013, 05:55 AM Tom Warren,
That could very well be the problem. ... May 25 2013, 07:47 PM Tom Warren,
I agree, you are getting very close to ... May 26 2013, 12:24 PM warrenoliver Some great ideas there Tom. I really appreciate e... May 26 2013, 03:31 PM jk76.914
Warren,
I agree, you are getting very close to... May 17 2015, 05:23 PM Tom Warren,
The #30 pin for the two relays are from... May 26 2013, 05:03 PM warrenoliver I must be missing something then. When i look at ... May 27 2013, 09:05 AM Tom Warren,
Take another look. Follow the lines ... May 27 2013, 09:45 AM warrenoliver Tom,
Aha! I think you may be on to it. Even... May 27 2013, 12:22 PM warrenoliver DAMN!!!!!! This thing is... May 27 2013, 03:36 PM warrenoliver I think I have finally tracked it down. With the ... May 27 2013, 07:28 PM Jon H. I find these electrical Gremlins to be the most fr... May 28 2013, 04:17 AM Tom Warren,
Very happy I could help. Glad things ... May 28 2013, 10:56 AM revhi109 I am also having issues with my fuel pump not comi... Mar 30 2015, 10:12 AM warrenoliver
I am also having issues with my fuel pump not com... Apr 1 2015, 07:20 PM flylarry If the relay works and a jumper between the fuse a... May 17 2015, 08:15 PM |
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