no you dont need to start engine, just turn key on. pump should come on

 

I checked this out yesterday. I first tried it (no blocking of return line) and got about 12 psi. Then I wrapped a part of the return line and pinched down, but not really hard, and jumped up to about 26 psi. I was afraid to pinch too much and damage the line. After this I noticed some gas pooled around the housing for the pressure regulator as well.

 

time for a new one

 

I'm not really sure where to go from here. I replaced the fuel pressure regulator, and nothing changed. So, I pulled the tank again and returned the Delphi pump to the retailer for another one. I just finished putting the new pump in, new fuel filter, checking all the lines and connections, etc.

When I turn the key, I get about 10 psi when the pump starts up/runs. If I turn the key off, wait a few seconds and do it again, it goes to 20 something to 30 psi. 3 turns of the key/pump cycles gets me to operating psi. I found out about the direct jumper connection to the fuel pump under the hood, and if I connect that to 12V the psi jumps up to 44 and maintains there as it should. What exactly is going on with this?

 

Check the manual and see where the pump is grounded. Clean that. if that does not fix it: Probe the power wire to the fuel pump, check the voltage drop when the pump turns on. You can then do the same thing with the fuel pump jumper. If those are different then the main circuit is starving the pump for voltage. Think could be a damaged wire or bad connector or relay that has built to much resistance.

 

Thank you for the suggestions.

I wish I had something better to report back, but I did find the fuel pump ground (under the drivers seat) and cleaned minor corrosion off that. This is unrelated I believe, but the system isn't holding even that 10ish psi of pressure anymore. When I turn the key, I get a jump to maybe 25 psi, and then it slowly backs down to zero. Before I could at least maintain 10 or so psi and "build up" the pressure with a few key turns. The direct connection still gets up to 44 psi but also loses pressure back to zero.

I don't know why this has changed, and this is very frustrating. Any chance I have some kind of injector problem?

 

maybe try pulling the injector racks with injectors still in the rack turn key on and see if you have leaking/failing injector. also pull the under hood fuse box lose and check the under side to see if you have corrosion or broken/damaged wires.

 

Unfortunately nothing is going anywhere with this problem. I pulled out the fuel rail and cleaned up the injectors, replaced the O-rings and put that back in with a new fuel pressure regulator. No change. Then I went ahead and replaced the fuel pump relay, and again no change. Everything in the system has been checked/replaced but I still have low pressure on key turn. For whatever reason after building the pressure to 20ish psi with a couple key turns the pressure held this time.

I would think you could rule out the fuel lines, as if there was a restriction I wouldn't get 40 psi when directly connecting 12V to the pump. Connector/wiring from the body to the pump itself must be fine then as well. Maybe it's something electrical before/after the relay to the connector....

 

did you turn the key on with the injectors hooked up but not installed yet to see if any of them were stuck open

 

I tried to do this, but had trouble really getting much clearance with the fuel rail pulled up and the lines still attached to the rail. I didn't see anything with the small amount of room I had though.

In the service manual it says to check the spark plugs for the best indication of a leaky injector, so I pulled all of those. Didn't have any indication of gas or abnormal deposits/fouling.