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Marc, Technician
Category: Car
Satisfied Customers: 1888
Experience:  33 years exp. automotive repair NYS emisisions repair cert.
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Recently i had problems starting my 95 Mazda millenia. The ...

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Recently i had problems starting my 95 Mazda millenia. The fuel pump was not coming on. Replaced the fuel pump but it still did not come on until i jumped it through the diagnostic box. Replaced the relay in the underhood fuse box. Still will not run unless I use the jumper wire. What else could it be??

The fuel pump relay is powered by the main relay check for power to the fuel pump relay while cranking if no power check fuses and power to and from main relay.

Locate the fuel pump relay test terminal in the engine compartment diagnoses box, it should be labeled FP. Ground the FP terminal with the key on and see if the fuel pump runs,. The FP terminal is tapped in to the ground control circuit of the fuel pump relay and when grounded the fuel pump relay should click.

If the fuel pump relay is not clicking when the test terminal is grounded, remove the relay and check that there is two terminals that have power when the key is on. If there is no power check for a blown fuse or broken wiring.

If the fuel pump relay is operating properly test for power to the fuel pump

Customer: replied 9 years ago.
Reply to Marc's Post: I ahve done those tests as I stated in my question. I tested to see if fuel pump was wroking by by grounding it and the pump comes on and the car cranks. I hear a clicking in the relay box when it is grounded. I tested the prongs the fuel pump relay plugs into and two of them light up. What else can I check??

Make sure you are getting the ground path to the relay when cranking the engine . this signal comes from the ECM (terminal 1U) if not check the wire between the ECM and the fuel pump relay if wire is good suspect ECM.

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