Low fuel pressure - Ranger-Forums - The Ultimate Ford Ranger Resource


SOHC - 2.3L & 2.5L Lima Engines Discussions and Topics specific to the Lima 4 cylinder engines

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 04-17-2015
Member
Thread Starter
 
Join Date: Apr 2015
Location: Hudson Florida
Posts: 6
Low fuel pressure

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!

----------

Disconnecting battery while checking everything else reset cel if that makes a difference.
Reply With Quote
  #2  
Old 04-17-2015
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,579
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.
Reply With Quote
  #3  
Old 04-17-2015
Member
Thread Starter
 
Join Date: Apr 2015
Location: Hudson Florida
Posts: 6
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.
Reply With Quote
  #4  
Old 04-17-2015
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,579
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
Reply With Quote
  #5  
Old 04-18-2015
Member
Thread Starter
 
Join Date: Apr 2015
Location: Hudson Florida
Posts: 6
Thanks Ron, I'll check it all out and let you know what I find
Reply With Quote
  #6  
Old 04-18-2015
cheese_man's Avatar
Member
iTrader: (1)
 
Join Date: Nov 2009
Location: arthur
Posts: 2,100
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
Reply With Quote
  #7  
Old 04-18-2015
Member
Thread Starter
 
Join Date: Apr 2015
Location: Hudson Florida
Posts: 6
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?

Last edited by chickenshackrob; 04-18-2015 at 02:55 PM.
Reply With Quote
  #8  
Old 04-18-2015
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,579
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.
Reply With Quote
  #9  
Old 04-18-2015
Member
Thread Starter
 
Join Date: Apr 2015
Location: Hudson Florida
Posts: 6
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?
Reply With Quote
  #10  
Old 04-18-2015
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,579
Not sure on that??

regular cab and extended cabs had different size tanks but never thought there was a wiring/connector difference
Reply With Quote
  #11  
Old 04-18-2015
Member
Thread Starter
 
Join Date: Apr 2015
Location: Hudson Florida
Posts: 6
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.
Reply With Quote
  #12  
Old 04-19-2015
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,579
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.
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
low fuel pressure jvrba1 SOHC - 2.3L & 2.5L Lima Engines 2 09-07-2014 01:36 PM
4.0 OHV Fuel Pressure / After-market Fuel Pump Rooks 4.0L OHV & SOHC V6 Tech 1 12-28-2011 12:52 PM
fuel pressure regulator or fuel pump fedupdon General Technical & Electrical 1 01-31-2011 07:04 AM
LOW LOW LOW RPMS JRacer 4.0L OHV & SOHC V6 Tech 23 05-07-2009 12:25 AM
Tire Pressure: How low is to low??? xp1ik99 Wheels & Tires Semi-Tech 12 08-15-2006 08:52 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 08:38 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.