Help!!! Fuel Pressure Info. Needed

[sluhbmet]

About a month ago my Ranger crapped out on me about 4 hours from home. The symptoms were a total loss of power and it would sometimes idle for a few seconds but die when I tried to accelerate. I suspected the fuel pump had gone bad since the truck had 205,000 miles on it and it had never been replaced. Plus I had been having to crank it longer than usual to get it started in the mornings. The repair shop confirmed it was the fuel pump and they replaced just the pump itself (Airtex-O'Reillys), the fuel strainer that fits on the end of whole assembly and the fuel filter to the tune of $430. It started and ran perfectly after that for about a week but the longer than usual cranking when trying to start in the mornings came back and now when I pull up to stop lights and push in on the clutch and come to a stop the idle sometimes drops to about 400-500 rpm and the engine starts to stumble and has died a couple of times, then it catches itself and revs back up. So I loaned the fuel pressure test kit (I don't think it had ever been used) from Autozone and I performed the fuel pressure test according to chapter 4/section 4 of the Haynes 93-97 Ranger repair manual. Fuel pressure was 30 psi with vacuum connected to regulator and 40psi with vacuum disconnected from regulator all while warmed up and idling. From what the book says, these are dead on perfect fuel pressure ranges. However, the book doesn't say anyting about what fuel pressure should be in the line after leaving it overnight, because this morning I hooked up the guage after letting it set all night and the pressure was 0 psi. And sure enough it took longer than usual to crank. Should the pressure in the line drop to zero overnight? Any advice or knowledge would be appreciated.

95 Ranger
4.0 V6
5-speed

 

[sluhbmet]

Nobody knows?

 

[Big Jim M]

You might have lost pressure when connecting the test kit.. I suggest installing the kit tonight and then starting the engine and then turning it off and looking at the resident pressure.. Then tomorrow morning raise the hood and check the pressure before starting the engine.
If it is zero again take the thing back to the shop and have them install a good pump in the tank..
Big JIm

 

[sluhbmet]

Thanks for the reply BigJim. It was much appreciated. I have just a little more information from performing another test after talking to three different service people from the local Ford dealerships in the area (Little Rock). So one dealership service rep. I talked to said the pressure should drop to zero overnight but should immediately come up to 35-45 psi when you turn the key on and the pump does it's initial prime for 2-3 seconds. Another dealership said that the pressure should reduce overnight but not go clear to zero (said it should hold between 10-20 psi), and the other was honest enough to say he didn't know the answer to my question. I don't think any of the people I talked to were mechanics, they just make the appointments for the service department. But they sure never offered to ask a mechanic for me though. So anywho, I thought what the heck and I left the pressure guage hooked up after getting home last night and tightened the fittings with a wrench. I checked it periodically and found that it takes 3 and a half hours for the pressure to go from 35 psi to zero. Is this normal??? After letting it set overnight (12 hours), I popped the hood and verified the guage was still on zero (like it would have changed-ha, ha). While still at zero psi I turned the key to the run position (did not start), and let the fuel pump do it's initial 2-3 second prime. I checked the guage and it was still on zero. It took two more pump cycles for the pressure to rise. That SUCKS... Glad this pump is under warranty. Not so glad the work was done by a shop that is currently 5'ish hours away from me.