What voltage should be delivered to the fuel pump on a 2001 Olds alero?? I'm reading 4.6 Volts (anticipated 12 volts). If 12 is required any suggestions on where to look for the decrease.

Gauge is probably bad. GM has a common issue with the gauge clusters going out.

If you can charge the battery with an external charger (for about 4 hours), then start the car, the problem is probably the alternator. Using a voltmenter, measure the voltage of the battery when the engine is not running. It should be about 12 volts. Start the engine and measure the voltage again. Now it should be at least 2 volts higher than the first measurement.

It is critically important for turbocharged models that the fuel pump receive the maximum amount of voltage available from the charging and wiring system. The alternator will try to maintain about 13.5 volts into the system. Resistive losses along the current path to the pump will reduce the voltage at the pump to something less than 13.5. If there are less than 12 volts at the pump, the amount of fuel flowing may be much less than expected and perhaps enough less to create lean air-fuel mixtures under heavy boost.

The instructions below show you how to bypass the resistor and relay that the turbocharged 3S models use to reduce voltage to the pump at idle. Please read through the instructions and look at the pictures before attempting this procedure. Before I did this relay/resistor bypass I measured the voltage at the pump using the method shown on my web page 2-fuelpumpvoltage.htm. At idle the pump was receiving about 6.7 to 7.0 volts. I saw from 10.6 to 10.8 volts as boost began to build and then watched that number drop to 10.2 to 10.3 volts as boost hit 15 psi or so and RPM approached redline. After performing the relay/resistor bypass I remeasured the voltage at the fuel pump with the following results.

Cold idle: 11 volts
Warm idle: ~10.6 volts
Warm idle after radiator fan kicked in: 10.35 - 10.55 volts
Acceleration and boost: ~10.5 volts

Check radiator fan relay first by changing with another with same part number in the fuse panel.If its good check for 12 volts at the fan switch coming in and going back out.If their is going back out replace fan switch.

i believe it should be 12 volts but not constant unless running, if you turn the key on it should read 12 volts for a short time

POWER GOING TO FUEL PUMP NOT TO FUEL PUMP.YOU CAN BUY AND REPLACE FUEL PUMP WIRES SEPERATELY.SOUND LIKE OLD WIRES HAS A OPEN CIRCUIT OR POOR GROUND.

You should have 12 volts at the gray wire.The black is ground make sure and use this wire also.This way you know the ground is good also.When you turn the key on you will only get battery voltage for 2 seconds with the key on.If you crank the motor then you will get battery voltage also.Hope this helps.Good luck.

should have 12 volts at pump during engine cranking. with key in "on" position, the fuel pump only gets voltage for 2 seconds if engine is not running. Read voltage during cranking. Check fuel pump relay in battery jucntion box under hood.

you have a voltage drop problem probably a coroded wire if you can open wire harness and do voltage checks down the wire until you find the bad spot and repair or you can run a bypass wire

start the car and let it run. leave it running and take the pos battery cable off...if it dies ur alternator is bad . if it stays running it usually means its good