What's up guys? I have a 99 ranger 2.5 with about 150000 on the odometer. I was getting a p0107 code Ford a long time and truck recently began stuttering and surging. Cleaned maf, new intake gasket, new throttle body gasket, cleaned injectors cleaned and checked all other sensors. Couldn't check fuel pressure until afterwards because I didn't have a gauge. Checked pressure and it is only reading 15 psi on three key turns. Can hear pump turn on and relay click. Could this be a bad fuel pump or something in the system elsewhere. Thanks in advance!

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Disconnecting battery while checking everything else reset cel if that makes a difference.

 

Unless you can smell gas from a cracked fuel line then you will need to replace pump assembly.
Fuel filter(in frame under drivers seat area) is only $10, I would replace that first BUT....I doubt it would cause that kind of pressure drop.

Fuel Pressure on '99 should be 65-70psi
It uses a returnless fuel system so there is no FPR(fuel pressure regulator), just the pump in the tank and the fuel injectors

Fuel pump assembly has a Check valve that holds pressure when pump is off, which yours isn't doing and pump itself reads like it is no longer pumping enough volume.

There is another part on the fuel rail, Pulse Damper, it has a vacuum line attached, but it doesn't effect pressure, and if it was leaking engine would be sucking in the gas thru the vacuum line and blowing black smoke out the exhaust.

Long shot would be a cracked fuel line in the tank, but you would still need to pull out the pump assembly to find it.

 

Thanks for the response. I just got my bed off and the wires leading into the pump are getting power. Looks like i will be spending $230 bucks this weekend on the whole assembly.

 

Could just be a cracked hose, fingers crossed


Oh, and P0107 is one of those oddball codes that mentions "baro sensor" and "MAP sensor", '99 has no actual MAP sensor or Baro sensor, it is just the way the Generic OBD2 is written.
The DPFE(differential pressure feed back) sensor, it is part of the EGR system, and it does read pressure, it has 2 hoses that goes to exhaust manifold and EGR tube, and an electrical connector.
Check the connector and the hoses

 

Thanks Ron, I'll check it all out and let you know what I find

 

first and foremost

replace the fuel filter before you do anything else

a sputtering engine is a sure sign of a nearly clogged fuel filter

 

I replaced the fuel filter with no change. I did a voltage drop test on the fuel pump this morning and when I turned the key with the power wire, the voltage went from 12.25 down to .33 volt. I read I should only have a voltage drop of .5 at the most. Is this normal for the returnless system? Am I reading the results wrong? Should the .33 be my reading or should I subtract the 12.25 from .33 to get my results fur the drop?

 

Drop test means both probes of the meter are hook to Positive or negative, but not both
So 1 probe on battery + and the other probe on 12v fuel pump wire
Or 1 probe on battery - and the other probe on Ground wire for fuel pump.

Then under .5v means wire is OK, so your .33 is OK, you are not testing the fuel pump, just the wiring and connectors with this test.

 

Ron you've been a big help! Thank you. I'm going to order the pump off of Rock auto. When I put in my truck it shows a couple different pumps. Mine has the black wiring harness on top I'm assuming for the charcoal canister in the back. Some of the pumps don't have this black push and turn connector, just the connector pigtail. Does it make any difference?

 

Not sure on that??

regular cab and extended cabs had different size tanks but never thought there was a wiring/connector difference

 

Just figured it out. It is a fuel tank pressure sensor. Most of the pumps say you need to reuse your old one. In my case I think I'm going to need another one. I could also try reusing mine and if it doesn't work, buy a new one.

 

Yes, that makes sense, it is part of the EVAP system, it monitors fuel tank pressure to make sure fumes are not being vented and polluting the air.