Fuel Pump



I have a 1996 Mazda mx6 (6cyl)with 150,000. I went to start it last week on a cold day and nothing happended. It turns over fine, but wont start. I was low on gas and it was freezing out. So I added heet and gas, and heated the underbody of my car. But still nothing. After looking into it more, I found the fuel pump is not turning on. I put a jumper wire in the diagnostic box from the fp to ground and I can hear it working. But now what? What does that mean?


It means you ran the fuel pump out of circuit. So there’s something wrong in the fuel pump circuit. This could be a fuse for the fuel pump, the fuel pump relay, or the computer.



With all those things done, you wonder if there is fuel pressure; or, do you wonder if the fuel pump is running when you turn the ignition key ON? Remember, the fuel pump will only run for two seconds EACH time the key is turned to ON. After the two seconds, the fuel pump is turned off by the engine computer. Turn the key ON, again, and the fuel pump runs for two seconds, again (unless, its maximum pressure switch shuts it off).
A fuel pressure gauge, connected to the fuel line, would answer a multitude of questions concerning fuel supply/delivery.


Will the car start and run with the pump jumped??


It won’t run without the jumper wire. I had someone turn the key while I had my ear up to the tank filler neck with the cap off. I tried to find a fuel pressure relief valve to see if there was any pressure, but I guess this car doesn’t have one. I’ll test it tonight.


No it didn’t.


Spray some starter fluid into the intake and see if the engine will fire then. If it does then the fuel system is at fault. The fuel pump relay is a good suspect. If there is still no action then you should make sure the plugs are firing.