Ok, so I am installing a fuel pump, trap door style. I replaced it 6 yrs ago and have had fuel issues recently. Went to replace it, buttened eveything up and no fuel pressure. Pulled it back out and here is how I troubleshooted.

*12V on the grey wire at the tank, when key in on position (obvously for only 2 sec)
*Hooked new fuel pump straight to battery, fuel pump good
*Checked continuity of intank harness, good

I can't think of anythnig I haven't checked, please help.

 

You should be able to hear it running when it primes. If you can hear it running and there's no pressure, maybe your little hose popped off inside the tank. If you can't hear it running, then doublecheck your ground back there and the FP relay. And you can turn it on by jumping the little FP test pigtail to 12V - It's hidden in the wire harness on the passenger side about 6 inches in front of the PCM. If all that stuff is working and the hose didn't pop off, then you probably got a regulator problem, although that is not as common. If you are trying to check residual pressure at the schraeder valve, you may have to take the little core out or it might not register on a test gauge because some of them dont depress the valve far enough to open it. If you have pressure at first then it falls off, maybe the new pump has a faulty check valve or dirt in it.

 

I can't hear it run, so I'm sure it's electrical. Just confused cause I thought I've checked everything.

 

I'm thinking about ordering a new intank pigtail. That's the only thing I can think of. Maybe the connector has gotten a bit old.

 

Could it be a bad ground? Where is it grounded to?

 

Did you check the ground, too? If power and ground it good to the body connector, then the trouble has to be past there. Use the fuel pump prime connector to aid your testing.

The ground location for the tank unit is in the LH rocker panel by the driver's seat.

 

I just checked that last night. Hooked 12V to the prime connector and got nothing. Pulled the plug off the body connector and had a good ground. Also took a seperate battery and went straight to the connector and also got nothing. The intank harness is a bit loose where it connects to the tank but I think it's still ok. I was going to get another one from Racetronix but they won't sell me one cause I can't proove I bought it from them.

 

On a 1996, the prime lead goes through the f/p relay. Maybe your relay/connection there is bad.

 

But is should have worked when I took the body connector off and applied voltage directly to the harness itself right?

Also, I don't remember seeing a relay dedicated for fuel pump (I may have overlooked it). Is it labeled as something else?

 

With the connector off, you would need to supply the ground, too. Did you do that?

The fuel pump relay is under the dead pedal in the LH kick panel.

http://shbox.com/1/fuel_pump_relay.jpg

 

With the connector off I supplied hot and ground from a totally seperate battery to the connector. Hot to the gray wire and ground to the black.

 

If you have good power and ground to the body connector, but not to the pump, you seem to have it narrowed down.

 

What should I check next. I hooked the pump directly to the battery and it worked.

 

If we can rely on what you have tested, it seems to be the harness (or harness connection) to the pump.

 

How about the wiring between the body connector and the pump?