924Board.org

[Benino]

My car died on my while I was driving yesterday. I checked different things and narrowed it down to the fuel pump. It wasn't pumping . I had some extra wire so I wired the fuel pump to the back lights on the car and turned them on. bzzzzzzzzz it started pumping. I drove home. My fuel pump relay only has about 15K miles on it. The fuses are all good. What I want to know is what all the leads for the fuel pump relay mean. If some one knows what the numbered pins stand for and can tell me that would be cool. That way I can jumper some of the leads and see if it is really the relay. I don't want to have to have my lights on in order to have my fuel pump pumping. Any fuel pump related electrical tips would be helpful. thanks. (oh I don't have the-in-the-tank pump installed. I only have the external one and my car is a 1980 N/A.

[bryanc]

Per Haynes fig 11.12a Oxy sensor and turbo.
#30 - Battery power (no fuse)
#87 - Battery power out to Oxy sensor control unit direct (no fuse) and thru fuse to fuel pump, warm up reg, supplemenary air valve, pwr to freq valve.
#15 - Power for relay coil and relay electronics. This is switched with the ignition keyswitch.
#1 - This is how the relay knows the engine is running. It is the tachometer output from the coil/ignition module.
#31 - Goes to the manifold pressure limiting switch. Non-turbo I think this goes to straight to gnd.

Since you have recently replaced the relay I would look for bad connections in the relay socket. I would also use a voltmeter to check for voltage and ground while the fuel pump ckt is in failure mode (doesn't do any good to check it when it works
If the battery voltage and gnds are good I would:

1)Put the meter on AC volts and bypass the fuel pump relay so you can start the car and check for AC voltage at the #1 pin. I'm not sure exactly what you will read but my guess is between 6 and 20VAC. If your tach quit working or is intermittent this would be a prime suspect.
2)Remove the bypass to the fuel pump and jumper pins 30 to 87 and see if the car will start and run. Be careful, pin 30 is wired directly to the battery and if you short it to ground you can destroy your wiring harness. This test is to see if the power and fuel pump wiring is correct.
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'84 944
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