Author Topic: Fuel Pump spacer missing  (Read 1342 times)

Offline TPI84GMC

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Fuel Pump spacer missing
« on: December 02, 2017, 06:03:13 PM »
Hey all, working on my 1984 GMC 1/2 ton 350 engine 2wd. I’m not getting any fuel pumped up to the carb. I’m thinking the mechanical fuel pump must be shot. I’m looking in my Haynes manual and it shows a spacer between the block and the pump. I am missing that! Could this be part of the reason the pump isn’t working? Or part of the reason it went bad?  Any help is appreciated!


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Offline Henry

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  • Posts: 331
Re: Fuel Pump spacer missing
« Reply #1 on: December 03, 2017, 09:14:05 PM »
Hi TPI:
Yes, if you have the stock fuel pump there should be a thin steel plate or spacer between the pump and block. The opening in the block is larger than the mating surface of the pump so the steel plate covers up the bottom part of the block opening. The stack up of gaskets and plate are correct in the Haynes manual. Was the pump working OK before you took it all apart? I think it is possible to still pump without the plate, but the travel of the pump arm may be pushed too far when it is all assembled without the plate and maybe this caused a premature failure of the pump. If you have been running it for a while like this, the gasket that should be between the block and plate has probably been keeping the oil from splashing out of the block under the pump....is this gasket also missing? If so, there really is not much oil splash here as the blcok opening is usually filled with grease. You can do a quick and dirty  test for your pump when it is off the engine by mounting it in a vice and hand actuating the lever and see if it will pump some gas. A real test is to get it mounted back on the engine and crank the engine and see if it flows. If you dont want to go through all this work, just buy a new pump and plate and hook it all up as the pumps are not that expensive and you will have peace of mind that the pump is OK and installed correctly. I think you can get a lifetime warranty on those Autozone pumps. I am not sure where you can get that plate...check with the car parts places first like Autozone or O'Reillys.
Regards,
Henry