Re: Multimeter Settings
+1
If you have access to the pump's wires, just give it 12V from a spare battery or charger and check pressure again. Beware that some cars have an electronic regulator module (ECM) that gets 12V from the relay/fuse box and then steps it down to a lower voltage based on the engine's fuel consumption needs. My car is like that (2002 Focus). When you turn the key to the ON position (but not start the car yet), the ECM will run the pump for a second or two on 12V and then cut out until the engine is started. Once started and idle, it will feed the pump a low voltage to keep it running at some minimum pressure.
I guess anything is possible. When my car started giving me problems with the fuel pump, I went to this old guy of a mechanic who has probably had more experience with older cars. He told me he's only seen fuel pumps go out slowly - usually dropping pressure over time and causing the car to loose power. It puzzled him quite a bit when I told him that my car would run great most of the time, but occasionally it would not start due to the fuel pump refusing to run. So he suggested to not change the fuel pump, as he wasn't sure this was the issue and he didn't want me to spend money on a repair he can't guarantee. So he said wait a little longer to see what happens and I listened.
But turned out it was the fuel pump. And as luck would have it, I got stranded on a rest area in the middle of the night (stopped to take a bathroom break and turned off the car, then I couldn't turn it back on again). I spend an hour trying to get the fuel pump running by cycling the ignition key between ON (not start) and OFF positions - a trick that used to work a dozen of times prior to the pump failing completely.
+1
If you have access to the pump's wires, just give it 12V from a spare battery or charger and check pressure again. Beware that some cars have an electronic regulator module (ECM) that gets 12V from the relay/fuse box and then steps it down to a lower voltage based on the engine's fuel consumption needs. My car is like that (2002 Focus). When you turn the key to the ON position (but not start the car yet), the ECM will run the pump for a second or two on 12V and then cut out until the engine is started. Once started and idle, it will feed the pump a low voltage to keep it running at some minimum pressure.
Originally posted by highspeed
But turned out it was the fuel pump. And as luck would have it, I got stranded on a rest area in the middle of the night (stopped to take a bathroom break and turned off the car, then I couldn't turn it back on again). I spend an hour trying to get the fuel pump running by cycling the ignition key between ON (not start) and OFF positions - a trick that used to work a dozen of times prior to the pump failing completely.
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