2001 Chevy Silverado No Fuel Pump Kick In

HIHOSILVERADO

MEMBER
2001 CHEVROLET SILVERADO

Engine Performance problem
2001 Chevy Silverado V8 Two Wheel Drive Automatic 100K miles

My 2001 Silverado stalled, restarted, then quick completely, luckily as I pulled into the parking lot. I read early posts and this is what I know: There is no fuel at the vacuum line to the Fuel Pressure regulator, no fuel pressure at the test port on the fuel rail with the switch in run or start, and I do feel a click at the fuel pump relay with switch in start. I do not hear the fuel pump kick in when the switch is turned to run. I did manage to pull the two electrical connectors off the fuel pump without dropping the tank and one socket on each connector reads around 5 Volts. I suspect this means my fuel pump is shot. Before I drop the tank and $250, is there anything else I should check?

9 Replies

JDL

MECHANIC
16,098 POSTS

As far as the pump motor, the gray wire is voltage, black is ground. The other wires should be for the gage sender unit.

If you have 5 volts on that gray with the engine cranking, that is too low. Battery has a full charge, the cables/wires all clean and tight on both ends?

Can you check the actual voltage at the fuel pump relay, 30 terminal, hot all the time.

You could run the pump without using the key, but, without proper voltage it won't matter.

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Sunday, March 29th, 2009 AT 1:44 PM

HIHOSILVERADO

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6 POSTS

The 5 volts was with the key in the run position, not cranking. The Battery reads just under 12 volts but stilll cranks fine. I will check both at the relay and while cranking ang post back later tonight.

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Sunday, March 29th, 2009 AT 2:16 PM

JDL

MECHANIC
16,098 POSTS

I believe the wiring harness for the fuel pump is a four wire connector.

There may be also a three wire connector for the fuel tank pressure sensor. The sensor uses a 5 volt reference. I can't tell what connector you were testing?

I won't be back till tomorrow. goodluck

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Sunday, March 29th, 2009 AT 3:52 PM

HIHOSILVERADO

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The connector I checked was the one with three contacts in line. I think the wires on the ends were black and gray and the gray one had 5 volts which increased to about 5.2 volts when I cranked the engine. Battery voltage is 12.2 v and that is what I get when I check the 30 connection to the fuel pump relay. So, I am guessing that I should get close to battery voltage on the connector that drives the fuel pump right?
I will go back today and check the other connector which is square and has 4 contacts. Also the picture isn't real clear, that one would seem to be the one you sent the picture of. I have also read that there is a connector between the cab and bed. I will check that out for corrosion.

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Monday, March 30th, 2009 AT 5:26 AM

JDL

MECHANIC
16,098 POSTS

The gray wire at the pump connector, at key on, will only have voltage for a couple of seconds, then the circuit goes dead without an rpm signal. With engine cranking, the available voltage at the pump will drop a couple of volts because of the starter.

You can run voltage to the pump without using the key, by using a jumper on the proper terminals at the relay, terminal 30 and 87, double check this, the relay may have a diagram on it, the symbol for the load side of relay usually looks like an open switch. The reading at the pump connector should be close to your 12.2. If you take a reading with the engine cranking, take the battery reading first, engine cranking. I think you'll find the reading dropped a couple volts, expect to find close to the same reading at the pump connector, engine cranking.