94 Century Fuel Pump Relay - Buick Forum - Buick Enthusiasts Forums

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Old 02-26-2012, 03:54 PM
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Default 94 Century Fuel Pump Relay

1994 Buick Century 3.1

Fuel pump relay is not powering the fuel pump. I was able at one point to jump the orange wire to the gray wire but it will not even do that now. I know the fuel pump works because I can jump from the battery to the gray wire and it will turn on.

I used a multimeter and tested the volts from the orange wire on the relay to ground and it is only reading about 1.18 to 1.3 volts.

Checked the fuel pump 15a fuse and all fuses inside and they are ok. I tried switching out the relay.

I am getting spark.

I checked green/white wire when key was turned on to check for 2 seconds of power, and it only went up to about 3v max before it went down.

There is no voltage to the green/white wire while turning the car over.

There is no security light on while cranking the car
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Old 02-26-2012, 05:17 PM
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I believe the PCM sends the voltage for the 2 second shot when turning on the key.
It would seem there is either a poor connection from the PCM to the fuel pump relay or the PCM is questionable.
I don't remember if the Century had an alternate circuit to energize the fuel pump in the event the relay failed. That circuit was through the oil pressure switch. There should be a grey wire at the oil press switch that also goes to the fuel pump. If you were to put 12 volts to that wire and the pump runs, it would confirm the problem is in the signal from the PCM. When the key is turned on there is a fuel pump relay control switch in the PCM.
Some models had more than one ign fuse hope you checked them all.
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Old 06-15-2012, 08:51 AM
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Default no power at fuel pump

i have no power at the plug in for fuel pump, cant find afuse marked fuel pump or the proper relay please help? thanks
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Old 06-16-2012, 06:42 PM
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FYI to others the problem was a ground wire from the relay to the battery that had cracked and was shorting. We had checked that wire visually, but never with a meter. This was a small crack that could not be seen with the eye.

roy webb, depending on what year car you have... I would find the fuel pump relay (near the passenger side headlight) and use a multimeter to check for power.
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94, buick, century, ecm, fuel, fueloil, function, fuse, location, locations, pressure, pump, relay, switch, system

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