99 tahoe no power to fuel pump


taxidermist
12-09-2006, 10:26 AM
I replaced the fuel pump( I did the bang on tank method to see if it was the pump and it started) now I cant get power to pump. I have read tons of threads here but they are not helping so far. I replaced the FP relay and checked the fuse. No melted plastic or soot on pigtail at the tank. I also replaced the battery and did not know about the anti theft thing on the radio, would this lock out the fuel pump?

Thanks,
Rob

777stickman
12-09-2006, 10:45 AM
ECM B fuse supplies power to the pump through the relay. The relay is controlled by the VCM. I'm not sure if you know that with the key in the "run" position and the engine not running that power to the pump only lasts about 2 seconds on the Gray wire. I think the security system only disables the injectors, but I'm not sure about the pump.

taxidermist
12-09-2006, 11:25 AM
ECM B fuse supplies power to the pump through the relay. The relay is controlled by the VCM. I'm not sure if you know that with the key in the "run" position and the engine not running that power to the pump only lasts about 2 seconds on the Gray wire. I think the security system only disables the injectors, but I'm not sure about the pump.


Yeah I know the time the wire is hot is short because it just primes the pump till it starts.

777stickman
12-09-2006, 11:48 AM
Pull the relay and match up pins 87 & 30 on the relay to the sockets. 87 is power feed from the ECM B fuse (hot at all times) and 30 is the gray wire feed to the pump. Check for 12v @ 87. Check for continuity from 30 to the pump plug. Jumper 87 & 30 and check for 12v at the pump plug. This only checks the power circuit to the pump and not the relay control circuit.

taxidermist
12-14-2006, 09:03 AM
Well I figured it out it was the pig tail connector at the pump. It looked great but when I plugged it in and raised the tank up it would not get a good connection. I jumped the relay and then used a long pry bar to go through the wheel well and move the pig tail and the pump kicked on. Thank you for all your help. It is at the shop getting re timed(intake job also was done) so it should be up and running soon.


Rob

777stickman
12-14-2006, 07:18 PM
Rob: Thanks for the post back and good job. Hopefully folks who read this post will learn from it, as I have..............Steve

LimitedTahoe00
12-14-2006, 09:32 PM
I Have A 2000 Limited I Had To Replace A Fuel Pump For.
You're Pump Is Probably Dead! If You Run Your Tank On Empty, And The Fuel Level Drops Below The Pump (exposing It), It Over Heats And Picks Up The Dirt At The Bottom Of Your Tank. Time For A New One. You Know Its Dead Because Your Fuel Gage Falls Below The "e."

Since I Never Let My Tank Go Down Pass The 1/4 Mark. Never Had A Problem Since.

taxidermist
12-15-2006, 12:22 PM
I Have A 2000 Limited I Had To Replace A Fuel Pump For.
You're Pump Is Probably Dead! If You Run Your Tank On Empty, And The Fuel Level Drops Below The Pump (exposing It), It Over Heats And Picks Up The Dirt At The Bottom Of Your Tank. Time For A New One. You Know Its Dead Because Your Fuel Gage Falls Below The "e."

Since I Never Let My Tank Go Down Pass The 1/4 Mark. Never Had A Problem Since.


You're Pump Is Probably Dead

I replaced the fuel pump( I did the bang on tank method to see if it was the pump and it started) now I cant get power to pump. I have read tons of threads here but they are not helping so far. I replaced the FP relay and checked the fuse. No melted plastic or soot on pigtail at the tank. I also replaced the battery and did not know about the anti theft thing on the radio, would this lock out the fuel pump?

Thanks,
Rob


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