Troubleshooting
Fuel Pump Current
It is never a good practice to replace a circuit protection fuse with one of higher amperage. The fuel pump circuit on the supercharged engine is different from the standard 3800 engine. This circuit uses a main fuel pump relay and a fuel pump speed control relay, along with a current limiting resistor. The fuel pump relay powers the speed control relay. Both relays are energized by the PCM during starting and normal operation. The speed control relay directs current through the resistor to the pump.When high fuel volume is required during increased engine loads or acceleration, the PCM de-energizes the speed control relay. The resistor is bypassed and direct current is supplied to the pump for full speed operation. This resistor is mounted under the battery tray on the frame rail and is exposed to battery acid and corrosion. You can locate the resistor between frame rail and washer reservoir. This may be your area of concern. Also check normal running amperage of the fuel pump. This should read approximately 7.50 amps. If the current draw is excessive, replace the pump.
Dear Roy,
I own a 1998 Buick Regal GS, VIN 2G4WF5212W1476173, with a 3.8L supercharged engine and a four-speed transmission. It has been blowing fuses for the fuel pump. It would seem to do it when I was taking off. Then after I put a new fuse in, it would be fine for a while.
I have had it in the shop at the dealership where I work and they can't seem to figure out what's wrong with it. A mechanic told me to try putting in a bigger fuse and driving the car to see if it blows. Well I tried that, and it hasn't blown.
I have been driving it like that for a few months now, but I would like to get it fixed right. Any thoughts would be very helpful.
Thanks,
Tyler Sampson, Auto Body Tech
Don Johnson Motors, Rice Lake, WI
It is never a good practice to replace a circuit protection fuse with one of higher amperage. The fuel pump circuit on the supercharged engine is different from the standard 3800 engine. This circuit uses a main fuel pump relay and a fuel pump speed control relay, along with a current limiting resistor. The fuel pump relay powers the speed control relay. Both relays are energized by the PCM during starting and normal operation. The speed control relay directs current through the resistor to the pump.When high fuel volume is required during increased engine loads or acceleration, the PCM de-energizes the speed control relay. The resistor is bypassed and direct current is supplied to the pump for full speed operation. This resistor is mounted under the battery tray on the frame rail and is exposed to battery acid and corrosion. You can locate the resistor between frame rail and washer reservoir. This may be your area of concern. Also check normal running amperage of the fuel pump. This should read approximately 7.50 amps. If the current draw is excessive, replace the pump.
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