How to free up a stuck fuel pump without dropping the fuel tank

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1,371
Location
NY
I just installed a brand new fuel pump/sending unit combination in a 1987 Chevy truck TBI 5.7. The pump has less than 5 miles on it but i the truck has sat for a couple months after those 5 miles were put on it. I went to start it the other day and I did not hear the fuel pump turn on. Today I did some checks and it seems the fuel pump is locked up. When I run 12v to the pump directly from the battery the pump clicks but does not whirr to life and pump fuel. I really do not want to drop the tank again. I tried banging on the tank while clicking the fuel pump. I also tried clicking the pump a bunch without banging on the tank and it has not come back to life. What are some things I can try to get the fuel pump to start working again without dropping the tank?
 
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17,448
Location
NH
What condition is the bed in? If it's crusty then breaking the bolts off might be problematic... but if it's crusty, is it any loss if you simply cut a hole to gain access to the pump? I presume they make patch panels to cover over the bed.

If nothing is rusty then the bed might be easy to remove.
 

joegreen

Thread starter
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1,371
Location
NY
I cannot take the bed off as it's super rusty and it's a utility body so it's very heavy. The fuel pump sits right between the bed and cab so I cannot cut an access hole. It's not a huge deal to drop the tank I just really don't want to do it. Also I am kind of interested in trying different methods at freeing up the pump. I thought about running the pump in reverse but the jumper wire I am using makes big sparks when I do that. I'm not opposed to dropping the tank I just wanted to hear some ideas first.
 

joegreen

Thread starter
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1,371
Location
NY
Blow air back into the pump?
I tried blowing air back through but I believe there is an anti drain back valve in the pump because I couldn't blow air back through. I also have a TBI pump not in the vehicle and I could only blow through it in one direction.
 
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Location
MA, Mittelfranken.de
I just installed a brand new fuel pump/sending unit combination in a 1987 Chevy truck TBI 5.7. The pump has less than 5 miles on it but i the truck has sat for a couple months after those 5 miles were put on it. I went to start it the other day and I did not hear the fuel pump turn on. Today I did some checks and it seems the fuel pump is locked up. When I run 12v to the pump directly from the battery the pump clicks but does not whirr to life and pump fuel. I really do not want to drop the tank again. I tried banging on the tank while clicking the fuel pump. I also tried clicking the pump a bunch without banging on the tank and it has not come back to life. What are some things I can try to get the fuel pump to start working again without dropping the tank?

What brand of pump is it?
 

joegreen

Thread starter
Messages
1,371
Location
NY
No offense but no surprise with that unit, that should not happen. Swap the pump itself out for a Bosch pump $30 Rock Auto and keep the sending unit.
I know it's a pretty cheap unit but I only drive the truck a few times per year. It's mostly a yard vehicle.
 

twouvakind

Site Donor 2021
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412
Location
New Jersey
Whatever works to unstick it, you can use that method the next time it sticks....you know it will(stick)at the most inopportune time...hopefully not a mission critical time
 
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25,551
Location
Upstate NY
Drop the tank and replace the pump with Bosch or OEM. Everything will be easy to get out. This will not be the last time you will be doing this. I had a 1993 Suburban with TBI. My truck came with waxy goo covering the area where the unit slides into the tank. Not sure if that was factory or someone's idea. I scraped the stuff out (along with all the road dirt) and everything was nice and clean. After I was done I reapplied wax from a toilet ring to keep it clean.

REMEMBER TO REPLACE THE SOCK EACH TIME.
 
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joegreen

Thread starter
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1,371
Location
NY
Alright so I think I ruined the pump trying to turn it on to many times because now it makes no noise. Before it stopped working I think I heard it turn on and start whirring but it sounded labored and no fuel came out.
 

joegreen

Thread starter
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1,371
Location
NY
Right now I'm draining the tank so it's easier to drop. Thanks for everyone's help. I had fun trying different ways to beat on the tank.
 
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Location
RI
I know it's a pretty cheap unit but I only drive the truck a few times per year. It's mostly a yard vehicle.

This logic using flawed. Look where it got you.

Replace it with an OEM or Bosch as previously suggested
 
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