73 D-Jet 3 port fuel pump, Is my fuel flowing right ?? Options

[David_S]

I decided that before I installed and plumbed my fuel pump that it may be a good idea to mess with it on the bench first. My fuel pump is on the bench and hot wiring it direct to a battery for power. If I use the "S" port for suction, I get no flow from the "D" port, and lots of flow from the "R" port. Is this right since it cant build any kind of pressure right now, or should I be getting fuel out of the "D" port instead of "R" ?? The fuel pump is all that I need to see if this thing will run again !!! Thanks in advance !!

[sfrenck]

Try this thread:

3-port pump fuel lines

[David_S]

I read that one last night, but it still doesn't explain why Iam not getting any fuel from the "D" port. If I am understanding the operation right, I should be getting flow out of the "D" port (to pressurize the fuel rails) and not the "R" port (to return fuel back to the tank). The way that it is working right now, my pump is sucking from the tank ("S" port), and just returning fuel back to the tank ("R" port), and not letting the system pressure up ("D" port).

[Dave_Darling]

At a guess, there is a blockage in the D port, which means all the fuel comes out the R port. I thin even if the spring-loaded valve for the R port were stuck open, you'd still get some flow out of the D port.

You can remove the pump part from the motor. Make sure you mark and take pictures; the pump parts can go on several different orientations (two or four for each of two pieces) and only one or two of those is correct. The four screws in the end cover are the only thing holding the pump on. You may be able to find and fix the blockage after you take it apart...

--DD

[JawjaPorsche]

I read that one last night, but it still doesn't explain why Iam not getting any fuel from the "D" port. If I am understanding the operation right, I should be getting flow out of the "D" port (to pressurize the fuel rails) and not the "R" port (to return fuel back to the tank). The way that it is working right now, my pump is sucking from the tank ("S" port), and just returning fuel back to the tank ("R" port), and not letting the system pressure up ("D" port).

Just asking: Are you testing fuel pump as closed system? What I mean are stimulating by having the D line go out and back with a Y connector to the R and the other to the gas source?

[David_S]

Blockage in the D port could be a possibility. I had the S port in my fuel jug, and the D port and R port were open with no T. When I powered the pump, I got fuel out of R and nothing out of D. I tried to block R and it would pressure up just like I think the D should pressure up. Hope that makes sense ......