QuestionQUESTION: I have a 1979 MGB that I just replaced the fuel pump in. It is an aftermarket OE replacement. The pump ran, fed fuel and the motor fired and ran. One day later I started the MG and I died shortly after. When turnin the key to ignition on, the fuel pump does not run and the vehicle won't start. Is there a fuse that coul have blown? Or some other issue?
ANSWER: Hi Brandon. No, there is no fuse in the circuit which powers the fuel pump. Either the white power wire is not delivering the necessary voltage, or the black wire is not a good earth (ground). I would connect a bulb in place of the pump and turn the ignition on. If the bulb fails to light up, you have a wiring fault. If the bulb does light up, you have a faulty fuel pump.
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QUESTION: The wiring is fine, the light lit up no problem. Is there a reason the pump would fail? Maybe a clogged line? I can hear it click when I hook up power but it is quiet and only one click. Also, what is the blue cylinder that connects to the power ide and is grounded to the body?
AnswerHi Brandon. If there was a blockage on the suction side, the pump would continually try to suck fuel. It only stops when it has pressurized the delivery side. Perhaps you have a blockage in the line to the carbs. Have you replaced the inline fuel filter recently?
You could try pulling the fuel delivery pipe from the carb and momentarily turning on the ignition. It should immediately spurt fuel. Do not do this with a hot engine or with any naked flames around and be ready to mop up the fuel with a disposable rag.
The blue cylinder under the hood near the fusebox is the ignition relay. If that failed there would be no power to the fuel pump. However, you rigged up a lamp which proved that the relay was OK.
