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Join Date: Oct 2009
Location: CA
Posts: 103
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Fuel pump relay help
Hi guys, trying to wire up a fuel pump relay for a 3.0 SC conversion in a 70 chassis. I've got everything done on the Bosch relay except the 30 pin, which should be for the fuel pump wiring. Question is, I don't see anywhere to access the fuel pump wiring in the engine compartment, is that correct? Certainly does not appear to be in the 14 pin connector. Thanks!
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08-13-2012, 10:43 AM
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ROW '78 911 Targa
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It is there. Try downloading the '78 wiring diagrams from pelican tech area.
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08-13-2012, 10:52 AM
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ROW '78 911 Targa
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Enabled by the CIS air meter switch if I remember correctly.
Yellow wire? Last edited by timmy2; 08-13-2012 at 11:02 AM.. |
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08-13-2012, 10:54 AM
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Location: CA
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Thanks. It's my understanding the SC chassis wiring is quite a bit different than the 70. I've got a '77 14 pin connector diagram here which doesnt seem to show it:
http://forums.pelicanparts.com/uploads18/77EngineWiring12972857231302701382.jpg I have the yellow wire running to the starter, which seems to be correct? |
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08-13-2012, 11:05 AM
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I am not sure with the 1970, but in the 1973 the fuel pump was mounted just in front of the drivers side rear wheel. It was unfused with no relay, rd/grn wire from the front fuse panel position 7 and branches off the harness before the 14 pin connector. The color changes to blue at a connector by the shock tower before going to the fuel pump.
The brown ground wire is picked up by the fuel filter mounting brackt, you will see a ground lug with multple wires.
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Ed 1973.5 T Last edited by E Sully; 08-13-2012 at 11:09 AM.. |
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08-13-2012, 11:06 AM
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Thanks Ed. In the 70 it's mounted in the front by the steering rack. There, the wires are both brown, the hot has a yellow stripe in it (which is not in the 14 pin). It's obviously possible that they change colors on the way back though I cant find a 70 specific wiring diagram anywhere...
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08-13-2012, 11:11 AM
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ROW '78 911 Targa
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Iirc, the 70 fp is always on. The 78 fp relay is enabled to run by the Cis air flow switch. That is what I was directing you to.
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08-13-2012, 12:31 PM
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Try this wiring diagram.
http://members.rennlist.org/911pcars/SL35-Master.pdf
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Ed 1973.5 T |
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08-13-2012, 12:42 PM
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Originaly it should have started out as a red/green at the non fused side of terminal 7. It would have power whenever the key was in the on or start position. Previous owners may have altered this. Yours has the switch in the air flow plate, and a relay so that the fuel pump will only pump when the engine is running.
Nice safety feature so that fuel will not pump in an accident. That's the beauty of older cars like my '73.5 that will keep the gas flowing if there is a fire till you turn it off. You would need to install the relay and run additional wires to the engine compartment to use this feature. Installing an inline fuse would be a good idea also. 
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Ed 1973.5 T Last edited by E Sully; 08-13-2012 at 01:07 PM.. |
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08-13-2012, 01:05 PM
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ROW '78 911 Targa
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When the air switch is activated it provides a path to ground so the relay picks up and runs the pump. You could just ground 30 and have pump turn on with ignition, I would run tbe wire back to engine comp for a safety feature.
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08-13-2012, 01:18 PM
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Registered
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Location: CA
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Hmm, so I tried jumping out the 30 to ground and it turns over but doesnt seem to be getting fuel. Though the fuel pump is running. I might have something else mixed up at this point.
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08-14-2012, 01:55 PM
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Heinz
The Other Woman
