I am putting a 5.3 in my 1981 chevy c10 pickup. I bought a drop in fuel sending unit for a f.i. pickup truck.

My question is, if i take about the ls1 fuel sending unit, can i use the pump out of an ls1 car for my truck?

 

That is what I am doing, I am using a El Camino EFI fuel sending unit with a 01 camaro fuel pump. I bought a new delco pump from a place on e-bay for $60, it was a kit to replace the pump in a stock 01 camaro sending unit. The only thing I had to do was take care of the output for the fuel venturi system in the new camaros. I used a compression fitting and brass cap to cap it off and then put a 1/16" hole in the cap to simulate the output of the camaro`s venturi system.

 

hmmm(thinking) you wouldnt just have some pictures of that would you?

I did the same thing on an 80 elcamino at my shop, and it is only putting out 40 psi all the way through the rev at the fuel rail. I have checked it before the fuel filter. Maybe the pump in the elco is just bad.

Are you talking about the small out output side of the pump?

 

Hmmmm never checked my fuel pressure, mabey I should. Yes I am talking about the small line. I do not have any pics of that part of my installation though. I put the large line right to the fuel sending unit just like with any other pump. For the small output on the pump I installed the thin piece of black tubing and on the end I put a compression fitting with a brass cap. I drilled a 1/16" hole in the cap. and just zip tied it so that it would spray at the side of the tank.

 

Maybe the pump isn't getting enough voltage. The smaller the voltage drop, the more the pump will pump. Does it have a relay, and large enough wire to get good power?
Are you running the hot wire directly off of the alternator?

More than likely, if the pump will make 40, it will also make the required LS1 53psi. It's just a motor, so it typically will not go bad a a slow rate. It usually works or doesn't.

I'm using a camaro pump/tank in my 83Elky. Runs great when it has the right voltage....

 

Are you using a truck motor and did you check while it was idling? i checked my fuel pressure yesterday 58psi motor off and fuelpump energized, 40psi motor idling. The FPR is vacuum referenced so it cuts fuel pressure at idle.

 

Guys sorry it has taken so long to get back to you. The engine is an 2000 Ls1 a4 setup. I checked the pressure with the engine idling and on a rev, it stays at 40 psi. I am using the tennessee auto fuel line kit found here: http://www.tennesseeauto.com/ls1fuellinekit.html. I have used this kit before, but not with a pump setup like this. I would really like to use the ls1 drop out pumps becuase i have so many around. To get the car started you have to prime the pump atleast 3 times for it to even burp and choke then it dies. Start it again, starts like normal but if you give it any gas it starts burping and coughing sometimes dies.Once you get it to idle, After it warms up a bit , the pcm seems like it compensates for the possible lack of fuel and runs (thats all i can say for it). Any help from that vague description would be helpful. This isnt my first swap and I havent had this much trouble.