81 K2500 fuel line routing

[colorado plow guy]

I picked up an 81 GMC K 2500 that’s pretty much all stock and un-butchered , but anyway the fuel pump was bad and while shopping around I could only find a fuel pump with a inlet and outlet port and a return, the one that came off only has inlet and outlet and no return, the truck has no return line installed. It is a dual tank with the selector valve, the selector valve appears to have a return port that is capped off, Would this be a sufficient place to install a return line and if so where would the fuel return to, it does not seem to be plumbed to the tank?

Looking between the cab and bed I can see the top of fuel module that seems to have either a vent line or return that is capped off but would require dropping the tank to acces it, Can anyone enlighten me the best way to approach this? right now I just got the return on pump capped off but I don’t want to over pressure my already pos quadrajet

 

[cheavyk10]

Interestingly, if you search fuel pumps on RockAuto, there are two line pumps available for the 1980 model year K20's but none for 1981's. Maybe you truck was a GM parts bin hold over.

 

[kennyw]

I would rather track down the correct pump and avoid adding the return lines. Like Dan mentioned, try changing to a year earlier to force the computer to pull up the correct part.

 

[colorado plow guy]

Ended up keeping the fuel pump with return, I think it might be better in the long run, trying to avoid flooding and vapor lock issues , I did source some factory steel lines from LMC which gave me a good diagram how it’s supposed to go with the selector valve

 

[fourwheelerjeff]

40987 without return
41216 with return
numbers still burned in my memory from my parts store days from 40 years ago

 

[dra1967pool]

I picked up an 81 GMC K 2500 that’s pretty much all stock and un-butchered , but anyway the fuel pump was bad and while shopping around I could only find a fuel pump with a inlet and outlet port and a return, the one that came off only has inlet and outlet and no return, the truck has no return line installed. It is a dual tank with the selector valve, the selector valve appears to have a return port that is capped off, Would this be a sufficient place to install a return line and if so where would the fuel return to, it does not seem to be plumbed to the tank?

Looking between the cab and bed I can see the top of fuel module that seems to have either a vent line or return that is capped off but would require dropping the tank to acces it, Can anyone enlighten me the best way to approach this? right now I just got the return on pump capped off but I don’t want to over pressure my already pos quadrajet

Hey try to find a truck manual for your truck! You want to buy one that just for year of your truck. Also there is a CD that you can see better on your computer!

 

[kennyw]

Hey try to find a truck manual for your truck! You want to buy one that just for year of your truck. Also there is a CD that you can see better on your computer!

View attachment 517279

Everything on that CD is probably available to download for free on CK5.