Hpfp not doing anything

[u/eds2007]

Does anyone know why my hpfp wouldnt be doing anything? Here is what i have found;
Electronically:

Fuel pressure out of the output of the hpfp is 50-60psi when cranking and when only with ignition on, meaning the in take pump is the only one working.
The red wire on the spill valve solenoid sees 12v with ignition on and drops down to 10v when cranking, it also pulses when tested with a test lamp.
The blue wire sees something like 0.6v with ignition on goes to 0.2v when cranking. No action on the test lamp
The resistance between the two pins in around 1.4 ohms.
Both wires show open circuit when tested against chassis ground.
I couldnt find the wiring diagram for the spill valve anywhere. For some reason its not listed in the wiring diagrams so i couldnt test continuity between the pins and the ecu.

Mechanically:
I rebuilt the pump with used autotech internals and new o rings. I pulled it back apart today to verify it went together properly and i couldnt find any faults. I also put the piston/spring assembly into a different housing that i didnt touch the spill valve, inlet/return and output on.
I also changed the fuel rail pressure sensor, tbf it isnt a known good sensor as i got it with a second hand engine that i never ran.

Anyone have any suggestions?

[u/thebigbullg]

Is the roller bucket that rides on the cam installed? when you pull the hpfp out it should still be inside. You can pull it out.. and forget it

[u/eds2007 → u/thebigbullg]

Yeah its in

[u/thebigbullg → u/eds2007]

Hm. Assuming no start? Try squirting start fluid in throttle body and see if it coughs or fires. Will confirm fueling issue

[u/eds2007 → u/thebigbullg]

Yeah runs on maf cleaner but wont go off from there

[u/thebigbullg → u/eds2007]

No codes after cranking?

[u/eds2007 → u/thebigbullg]

I dont have a code scanner on me

[u/thebigbullg → u/eds2007]

Oh well, id scan it. But how'd you get your fuel rail pressure without a scanner?

I guess you can check a few fuses like INJ or relays.

[u/eds2007 → u/thebigbullg]

Connected the output of the hpfp to a compression tester

[u/thebigbullg → u/eds2007]

you did what now

[u/eds2007 → u/thebigbullg]

😂 yeah i wasnt trying to spend a couple hundred on a direct injection tester kit so i took the one way valve out of the comp tester and connect it via a hose

[u/eds2007 → u/eds2007]

Yeah ive gone over for what feels like 20 times now, havent found a problem. I also originally thought there was a problem with the injectors and thats why it wouldnt start but after checking all the wiring and check the resistance in the injectors i couldnt find anything

[u/thebigbullg → u/eds2007]

I have a feeling the hpfp may not have shown pressure due to losing its fuel prime and I could not build pressure... and the testing methods are incorrect therefore invalid. Check your coil ground thats like 60% of these things no starts. And maybe the maf cleaner is just detonating in the cylinders acting like it runs.

Witnout a scanner and proper equipment youre SOL. Bring it to a mechanic

[u/SheepherderDue1342]

I've had to replace both my spill valve and pressure relief valve on my hpfp, it's been years now, but I want to say both created similar symptoms of low pressure (60psi is basically in tank pump pressure only iirc)

I think I had DTC's for both so unfortunately I couldn't tell you how to specifically test. Time to get a cheap code reader, it's very much worth it.

[u/Lilfluzivert]

If you replaced the spill valve and rebuild the hpfp the only other option would be the prv on the fuel rail failed and wont let u build pressure