I HAVE A 97 PONTIAC SUNFIRE THAT WILL CRANK, BUT WILL ONLY START WHEN I HEAR THE FUEL PUMP RUNNING. MY MECHANICT SAYS THAT THE FUEL PUMP IS NOT GETTING ELECTRICITY. HE IS NOT AN ELECTRIC AUTOMOTIVE MECHANIC, SO HE DOES NOT KNOW WHAT TO DO. WHAT NEEDS TO BE CHECKED WHEN THE FUEL PUMP IS NOT GETTING ELECTRICAL CURRENT. HOW DO I FIX IT? .
Under the hood in the power distribution center is the fp/inj fuse, and fuel pump relay. Check the fuse. If it’s not blown then swap relay with one that’s not important to the running of the engine. If the fuse is blown, then the gray wire that powers the pump is grounding someplace or the pump is drawing too many amps. NEVER use a higher amp fuse than what the circuit calls for which on this one is 20 amps.
Get a second opinion from a good independent mechanic. Your “mechanic”…and I use the term loosely…may be thinking that the fuel pump is not getting current. When some fuel pumps start to fail…they will come on intermittently. In addition, a bad key switch could be causing your problem. Follow @petepeters advice before you visit that good independent mechanic.
WHY ARE YOU YELLING AT EVERYONE ?!
You said “BUT WILL ONLY START WHEN I HEAR THE FUEL PUMP RUNNING.”. I’m reading it like missileman and assuming that you’re saying that sometimes you hear the fuel pump prime up and the car starts. But sometimes you don’t hear the fuel pump prime up and then it will crank but not start.
Is that the story? Or are you now just in a position where the pump doesn’t run at all? These are two different things. So clarify.
There’s a half dozen or more reasons why the fuel pump wouldn’t run when it is supposed to. The first thing would be to measure the voltage at the fuel pump, back probe the connector. I assume that is what your mechanic already did, and he finds there is no or low voltage there. I have no experience with this particular car, but on my Corolla I’d expect either the main engine relay or the fuel pump relay, or associated fuse. If it wasn’t any of those, I’d next suspect a corroded connector in the high current wiring between the fuel pump relay and the fuel pump. That’s a common problem, the connector will corrode a little, which increases the resistance, then it heats up even more, which makes it corrode more, etc etc. It’s a downhill slide once a high current connector starts to corrode. Sometimes this type of problem can be intermittent, it will work one day, and not the next. Affected by temperature, humidity, jiggling.
I had a VW Rabbit years ago where the wiring inside the relay plate – behind where the fuel pump relay plugged in – did this. The shop had to entirely bypass the relay plate with separate wiring to fix it.