Fuel pump problems?

[SlowVette72]

Im checking out a 2001 ranger for a guy, and it seems to have intermittent fuel problems. I checked fuel pressure, and this is what I got. With the key on the guage went to about 15psi. With the ignition disabled, and cranking it steadily went to about 50psi, and stoped there. With the ignition hooked back up, I cranked it over and it fired up. The guage then went to 64 psi. Does anyone know if this sounds about right for a 3.0ltr ranger. I dont work on Fords a lot, so Im not exactly sure. I just want to rule out the fuel pump if its not the problem. He sayes that sometimes it cranks quite a while before it fires up. I just havent been able to get it to act up while Im checking pressure. Just thought Id rule out fuel problems before I moved on to spark. Thanks.

[2000mudder]

ford is a high pressure system. if you have that much pressure, i'd say it's not a fuel issue,unless injectors are clogged.any check engine light codes?

[SlowVette72]

Originally Posted by 2000mudder

ford is a high pressure system. if you have that much pressure, i'd say it's not a fuel issue,unless injectors are clogged.any check engine light codes?

No fault codes at all. It seems to be very intermitent. The owner actually told me it doesn't do it very much when he has a full tank of gas. I dont see where that could change anything, but at this point Im willing to consider anything. So you say thats adequte fuel pressure for that motor? I guess I'll check the coil pack next. The problem he descibes just seems like its loosing its fuel prime before it builds up pressure again. Thanks for the response 2000mudder, hope to hear back from you.

[freeclimber]

I'm just recalling these numbers from off the top of my head, but the fuel rail psi should be 35-45psi when you turn the key on and the pump spins up.
A full tank provides more cooling to a heat sensitive fuel pump, keeps floaties from being sucked into pickup (debris and water).
Low fuel pressure will cause long cranking times. Also, system might be losing pressure. Did you leave tester attached for 20minutes to see if pressure dropped too much w/ engine off?

[SlowVette72]

Originally Posted by freeclimber

I'm just recalling these numbers from off the top of my head, but the fuel rail psi should be 35-45psi when you turn the key on and the pump spins up.
A full tank provides more cooling to a heat sensitive fuel pump, keeps floaties from being sucked into pickup (debris and water).
Low fuel pressure will cause long cranking times. Also, system might be losing pressure. Did you leave tester attached for 20minutes to see if pressure dropped too much w/ engine off?

I probably should have left the guage hooked up for a while after it was off, but I didnt. So you think that 15psi with the key on sounds too low? Like I said, I dont mess with a lot of Fords so Im not exactly sure on the specs. He does keep telling me that it only seems to do it when its low on fuel. Could that possibly have anything to do with the problem. He says when its low on fuel(around a quarter of a tank), he can crank it forever and it wont start. then he says he turns the key off, and trys to crank it again and it starts right up. It had a full tank when he brought it to me, and I coudn't get it to duplicate the problem. If what you say is true about the pressure with the key on...... I would imagine that would be something to look at. If its fuel level thats causing the problem, are the sending units somehow related to anything on the pumps with these trucks? Thanks for your imput freeclimber, hope to hear from you soon.

[sp3edr4cer]

if it is happening more when his tank is not full i would say there is trash in the tank and stopping up the filter on the end of the fuel pump but when he fills it up it causes the in rush of gas to remove the trash from the out side of the filter and the trash settles some where else or is floating

[freeclimber]

When you turn the ignition cyl to the "on" position, it triggers the fuel pump to operate for two seconds in order to provide adequate pressure for startup. I don't believe 15psi is adequate for ANY vehicle.
Good luck tracking down the root cause.

[SlowVette72]

Originally Posted by freeclimber

When you turn the ignition cyl to the "on" position, it triggers the fuel pump to operate for two seconds in order to provide adequate pressure for startup. I don't believe 15psi is adequate for ANY vehicle.
Good luck tracking down the root cause.

Thanks freeclimber. I would agree that 15psi doesn't seem like enough pressure. Im going to check it once more before I fully blame the pump. Im just begining to think that where my problems at.

[freeclimber]

make sure to check the pressure regulator before replacing the pump.

[SlowVette72]

Originally Posted by freeclimber

make sure to check the pressure regulator before replacing the pump.

How do I go about checking the regulator to see if its good or not?

[Psychopete]

One way I've heard is to check to see if there is gas in the vacuum line from your upper intake manifold.

Pete

[Psychopete]

Oopps, I forgot I wasn't in a 2.9 forum.... I have no idea on the newer Rangers. I've only worked on first gen. Still might be a vacuum line from your intake, I am not sure on how much the design has changed from 1986 - present.

Pete