Fuel Pump Primes while in on position before starting, doesn't kick on after starting
11-01-14, 04:01 PM
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Fuel Pump Primes while in on position before starting, doesn't kick on after starting
'85 GS
After having several problems and replacing the Fuel Pump Relay, Trailing Ignition Coil, and Trailing Ignitor, I've hit a road block.
As the title says, the fuel pump primes the lines prior to starting the car. The engine will run for about a minute, minute and a half before all of the fuel is exhausted.
If I hardwire the fuel pump always on it drives like a dream.
What controls whether the fuel pump needs to kick on?
EDIT: It should be noted I did not put a mazda relay in there, I used a standard 30, 85, 86, 87 relay if that makes any difference.
After having several problems and replacing the Fuel Pump Relay, Trailing Ignition Coil, and Trailing Ignitor, I've hit a road block.
As the title says, the fuel pump primes the lines prior to starting the car. The engine will run for about a minute, minute and a half before all of the fuel is exhausted.
If I hardwire the fuel pump always on it drives like a dream.
What controls whether the fuel pump needs to kick on?
EDIT: It should be noted I did not put a mazda relay in there, I used a standard 30, 85, 86, 87 relay if that makes any difference.
11-01-14, 05:54 PM
#2
If you can jumper the fuel pump relay connector and it works then the problem is with that circuit. You know the 12v is there, but the relay may not be getting a good ground. I suggest getting the wiring diagram for that circuit and tracing and verifying all inputs/outputs of the fuel pump relay connector.
11-01-14, 06:03 PM
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The thing I don't understand is that that in the on position, the fuel pump is running. I can hear it running. I feel the relay click on. It primes the carb and provides enough fuel to run for about a minute and a half. It clicks off after I start it up.
Do you still think it is a bad ground?
I still think it is some input to the computer or something else causing it to not think it needs fuel.
Do you still think it is a bad ground?
I still think it is some input to the computer or something else causing it to not think it needs fuel.
11-01-14, 07:16 PM
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i had that happen to one of mine, it was a bugger to figure out! in mine the ECU was bad, so i just jumpered the relay. the 79-83's just have the fuel pump hooked to the ignition switch
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