low fuel pressure
#1
low fuel pressure
Good evening folks. I have a 2.5 ranger that has a serious lake of power.
Currently I'm tracing out several things. One I have a lean condition or so the computer tells me. I've cleaned my K&N air filter, replaced my fuel filter, and checked my fuel rail gas pressure which is 42 psi. Not good but not terrible. Should be 60 to 65. Checked voltage going to the pump..12.4 volts. Just for kicks I checked the fuel dampener, and no gas coming out of vacuum port. And noticed a fluctuation in idle almost like a surging. So I believe it is working. I've unplugged my egg and didn't notice a difference warm or cold engine, so that may be my problem. I will replace the egg asap. Can someone he me out. Why the low pressure? is it bad enough to cause the lean condition?
Any help would be appreciated.
Currently I'm tracing out several things. One I have a lean condition or so the computer tells me. I've cleaned my K&N air filter, replaced my fuel filter, and checked my fuel rail gas pressure which is 42 psi. Not good but not terrible. Should be 60 to 65. Checked voltage going to the pump..12.4 volts. Just for kicks I checked the fuel dampener, and no gas coming out of vacuum port. And noticed a fluctuation in idle almost like a surging. So I believe it is working. I've unplugged my egg and didn't notice a difference warm or cold engine, so that may be my problem. I will replace the egg asap. Can someone he me out. Why the low pressure? is it bad enough to cause the lean condition?
Any help would be appreciated.
#2
Since you can test your fuel pressure then you need to test it after you shut down the engine.
You say it is 42psi with engine running, after you turn off the key watch the pressure, it should stay the same not drop down.
Yes 42psi is low for a '98, too low really, and a problem.
The fuel pump has a check valve built-in that prevents "back flow" when engine is off and also with pump running.
This is the only "fuel pressure" part of the returnless system, damper just absorbs pressure changes when injectors open and close.
There are also fuel line connections in the tank that can leak, this will lower pressure over all.
The fuel filter can effect pressure as well, as it gets clogged up the volume of fuel it can pass is less and less so pressure will go down, for $10 it is worth replacing every 4 or 5 years.
The computer expects 60psi of pressure, it has no way to monitor the pressure.
It opens the injectors for a specific amount of time to add fuel to the air in the intake based on 60psi pressure.
If pressure is lower than say 50psi then computer has to open injectors longer, to maintain correct fuel/air mix(O2 sensor data), the computer has pre-set limits for injector open time, if it reaches that limit and O2 sensor still reports lean exhaust then computer will turn on CEL(check engine light) to let you know there is a problem.
"egg"??
ECT sensor on the 2.3l(not sure for the 2.5l) is located on the drivers side of the block towards the front of the engine, under the intake.
ECT sensor has TWO wires, and tells the computer the engine temp, for cold(choke mode, open loop) or warmed up(closed loop, O2 sensors used)
ECT sensor looks similar to the Coolant temp SENDER, the sender has ONE wire that goes to the dash board temp gauge.
These two coolant temp devices are not connected together or shared.
You say it is 42psi with engine running, after you turn off the key watch the pressure, it should stay the same not drop down.
Yes 42psi is low for a '98, too low really, and a problem.
The fuel pump has a check valve built-in that prevents "back flow" when engine is off and also with pump running.
This is the only "fuel pressure" part of the returnless system, damper just absorbs pressure changes when injectors open and close.
There are also fuel line connections in the tank that can leak, this will lower pressure over all.
The fuel filter can effect pressure as well, as it gets clogged up the volume of fuel it can pass is less and less so pressure will go down, for $10 it is worth replacing every 4 or 5 years.
The computer expects 60psi of pressure, it has no way to monitor the pressure.
It opens the injectors for a specific amount of time to add fuel to the air in the intake based on 60psi pressure.
If pressure is lower than say 50psi then computer has to open injectors longer, to maintain correct fuel/air mix(O2 sensor data), the computer has pre-set limits for injector open time, if it reaches that limit and O2 sensor still reports lean exhaust then computer will turn on CEL(check engine light) to let you know there is a problem.
"egg"??
ECT sensor on the 2.3l(not sure for the 2.5l) is located on the drivers side of the block towards the front of the engine, under the intake.
ECT sensor has TWO wires, and tells the computer the engine temp, for cold(choke mode, open loop) or warmed up(closed loop, O2 sensors used)
ECT sensor looks similar to the Coolant temp SENDER, the sender has ONE wire that goes to the dash board temp gauge.
These two coolant temp devices are not connected together or shared.
Last edited by RonD; 09-07-2014 at 08:33 AM.
#3
Ok. With key off gas pressure in the fuel line remain constant 42psi for upto 5 minutes after running the engine.
I meant egr but my tablet auto corrects spelling.
Checked for exhaust leaks before the cat and found a leaking gasket so I replaced it.
No change. Did this a few weeks ago. Still no power.
I guess replacing the fuel pump is next. I've done this before but can't remember how long ago, probably several years. Anyway its not the original. Any other areas I should check?
I meant egr but my tablet auto corrects spelling.
Checked for exhaust leaks before the cat and found a leaking gasket so I replaced it.
No change. Did this a few weeks ago. Still no power.
I guess replacing the fuel pump is next. I've done this before but can't remember how long ago, probably several years. Anyway its not the original. Any other areas I should check?
#4
#5
2.5l was only used from 1998 to 2001 mid year, in Rangers
It should just have a 2 port fuel filter
The 3 port models were used starting in 2001 on V6 Rangers and on the 2.3l DOHC after mid-2001
In 1998 Rangers got new computer software to use a higher fuel pressure, and a "Returnless" fuel system, 1997 and earlier had 2 fuel lines to the engine bay, an IN and a Fuel Pressure regular on the engine with a Return line, in 1998 and up they just had the IN fuel line in engine bay
In 1998 the Fuel Pressure Regulator(FPR) was moved to inside the fuel tank
It was connected directly to the fuel pumps OUT hose to maintain a fuel pressure of 60psi OUT to the filter and then to the engine
So the fuel filter just had 2 ports, IN from FPR in the tank and OUT to engine
Gas tank--pump----FPR----------------------filter-------------------------------------------engine
There was a problem in that pressure varied too much at the engine end with this setup, usually not noticed much by drivers but with the new higher horse power 4.0l SOHC engine coming in 2001 a solution was needed
So in 2001 Ford added the 3 port filter
The pumps OUT ran directly to filter
The 3rd port ran back to the tank to the FPR, so these two ports are open to each other inside the filter
The FPR could then maintain a more stable 60psi pressure overall than when connected directly to the pump
So short Return line was added, but its still called a Returnless system
It should just have a 2 port fuel filter
The 3 port models were used starting in 2001 on V6 Rangers and on the 2.3l DOHC after mid-2001
In 1998 Rangers got new computer software to use a higher fuel pressure, and a "Returnless" fuel system, 1997 and earlier had 2 fuel lines to the engine bay, an IN and a Fuel Pressure regular on the engine with a Return line, in 1998 and up they just had the IN fuel line in engine bay
In 1998 the Fuel Pressure Regulator(FPR) was moved to inside the fuel tank
It was connected directly to the fuel pumps OUT hose to maintain a fuel pressure of 60psi OUT to the filter and then to the engine
So the fuel filter just had 2 ports, IN from FPR in the tank and OUT to engine
Gas tank--pump----FPR----------------------filter-------------------------------------------engine
There was a problem in that pressure varied too much at the engine end with this setup, usually not noticed much by drivers but with the new higher horse power 4.0l SOHC engine coming in 2001 a solution was needed
So in 2001 Ford added the 3 port filter
The pumps OUT ran directly to filter
The 3rd port ran back to the tank to the FPR, so these two ports are open to each other inside the filter
The FPR could then maintain a more stable 60psi pressure overall than when connected directly to the pump
So short Return line was added, but its still called a Returnless system
#6
2.5l was only used from 1998 to 2001 mid year, in Rangers
It should just have a 2 port fuel filter
The 3 port models were used starting in 2001 on V6 Rangers and on the 2.3l DOHC after mid-2001
In 1998 Rangers got new computer software to use a higher fuel pressure, and a "Returnless" fuel system, 1997 and earlier had 2 fuel lines to the engine bay, an IN and a Fuel Pressure regular on the engine with a Return line, in 1998 and up they just had the IN fuel line in engine bay
In 1998 the Fuel Pressure Regulator(FPR) was moved to inside the fuel tank
It was connected directly to the fuel pumps OUT hose to maintain a fuel pressure of 60psi OUT to the filter and then to the engine
So the fuel filter just had 2 ports, IN from FPR in the tank and OUT to engine
Gas tank--pump----FPR----------------------filter-------------------------------------------engine
There was a problem in that pressure varied too much at the engine end with this setup, usually not noticed much by drivers but with the new higher horse power 4.0l SOHC engine coming in 2001 a solution was needed
So in 2001 Ford added the 3 port filter
The pumps OUT ran directly to filter
The 3rd port ran back to the tank to the FPR, so these two ports are open to each other inside the filter
The FPR could then maintain a more stable 60psi pressure overall than when connected directly to the pump
So short Return line was added, but its still called a Returnless system
It should just have a 2 port fuel filter
The 3 port models were used starting in 2001 on V6 Rangers and on the 2.3l DOHC after mid-2001
In 1998 Rangers got new computer software to use a higher fuel pressure, and a "Returnless" fuel system, 1997 and earlier had 2 fuel lines to the engine bay, an IN and a Fuel Pressure regular on the engine with a Return line, in 1998 and up they just had the IN fuel line in engine bay
In 1998 the Fuel Pressure Regulator(FPR) was moved to inside the fuel tank
It was connected directly to the fuel pumps OUT hose to maintain a fuel pressure of 60psi OUT to the filter and then to the engine
So the fuel filter just had 2 ports, IN from FPR in the tank and OUT to engine
Gas tank--pump----FPR----------------------filter-------------------------------------------engine
There was a problem in that pressure varied too much at the engine end with this setup, usually not noticed much by drivers but with the new higher horse power 4.0l SOHC engine coming in 2001 a solution was needed
So in 2001 Ford added the 3 port filter
The pumps OUT ran directly to filter
The 3rd port ran back to the tank to the FPR, so these two ports are open to each other inside the filter
The FPR could then maintain a more stable 60psi pressure overall than when connected directly to the pump
So short Return line was added, but its still called a Returnless system
mine is the 2001 2.3 the fuel seems to be going to the pump then directly into the 3 port fuel filter but I’m not so sure it’s the right piece as the fuel Dosent even go to the rail it just goes right through the filter to the return line
that being said if I clamp the return line the. The truck will build around 40 psi but that isn’t enough
#7
2.3l is a different story, it will have a 3 port filter
It reads like the in tank FPR is bad
Pump, as well which is OK since they are both part of the Fuel Pump assembly
Pump is capable of 80+psi
If you blocked the return you should see that
So the FPR might be OK............it should open at 55+psi
Take the bed up or off and replace the fuel pump assembly
It reads like the in tank FPR is bad
Pump, as well which is OK since they are both part of the Fuel Pump assembly
Pump is capable of 80+psi
If you blocked the return you should see that
So the FPR might be OK............it should open at 55+psi
Take the bed up or off and replace the fuel pump assembly
#8
Here's the Motorcraft fuel filter for my 2000 Ranger 2.5l. Motorcraft FG-1071
https://www.autozone.com/filters-and...071/537934_0_0
Just check the fitment guide before getting one for your Ranger.
Here's the Duralast fuel filter I currently have on my truck since last April. Duralast FF870DL
https://www.autozone.com/filters-and...0dl/442146_0_0
https://www.autozone.com/filters-and...071/537934_0_0
Just check the fitment guide before getting one for your Ranger.
Here's the Duralast fuel filter I currently have on my truck since last April. Duralast FF870DL
https://www.autozone.com/filters-and...0dl/442146_0_0
#10
Don't feel bad Ron. The more I learn about this truck, the more I scratch my head. Some things on the VIN sticker don't line up with what's on the truck. It's been hell trying to track down the right parts.
I don't know if they're just like this from 1998 to 2000, or I just have a weird one off. Maybe it was built on a Friday and they grabbed whatever was left in the bins after the sticker was printed, who knows.
But I can confirm it's a 3 port fuel filter. I had taken pictures when I replaced mine last year but I can't find them or I would post them for future reference.
I don't know if they're just like this from 1998 to 2000, or I just have a weird one off. Maybe it was built on a Friday and they grabbed whatever was left in the bins after the sticker was printed, who knows.
But I can confirm it's a 3 port fuel filter. I had taken pictures when I replaced mine last year but I can't find them or I would post them for future reference.
#13
needs to be replaced
You can always use the links I posted, then put your truck's information in to get the proper fuel filter.
The original post by jvrba1 is in reference to a 2.5L, hence the info for a 2.5L. You might want to start your own thread so you get the right information, and so does he.
#14
In 1998 and up Rangers the Fuel Pressure Regulator(FPR) is in the gas tank
Its hooked directly to the fuel pump if you have a 2 port filter
It hooked to the 3rd port if you have a 3 port filter
FPR is set at 60psi pressure(+/-7psi), it uses a spring/valve setup, which are very reliable, but can break like anything else, just very rare
The pump can send out 80+psi, but can get weak
If you are only showing 40psi at the engine then it could be an FPR OR a Pump issue, but since they are BOTH part of a replacement assembly it doesn't matter, BOTH are replaced at the same time
This is assuming your Test Gauge is accurate, lol
Just make sure you get the correct assembly that has the 2 fuel line hookups not just one(2 port filter)
Its hooked directly to the fuel pump if you have a 2 port filter
It hooked to the 3rd port if you have a 3 port filter
FPR is set at 60psi pressure(+/-7psi), it uses a spring/valve setup, which are very reliable, but can break like anything else, just very rare
The pump can send out 80+psi, but can get weak
If you are only showing 40psi at the engine then it could be an FPR OR a Pump issue, but since they are BOTH part of a replacement assembly it doesn't matter, BOTH are replaced at the same time
This is assuming your Test Gauge is accurate, lol
Just make sure you get the correct assembly that has the 2 fuel line hookups not just one(2 port filter)
#15
In 1998 and up Rangers the Fuel Pressure Regulator(FPR) is in the gas tank
Its hooked directly to the fuel pump if you have a 2 port filter
It hooked to the 3rd port if you have a 3 port filter
FPR is set at 60psi pressure(+/-7psi), it uses a spring/valve setup, which are very reliable, but can break like anything else, just very rare
The pump can send out 80+psi, but can get weak
If you are only showing 40psi at the engine then it could be an FPR OR a Pump issue, but since they are BOTH part of a replacement assembly it doesn't matter, BOTH are replaced at the same time
This is assuming your Test Gauge is accurate, lol
Just make sure you get the correct assembly that has the 2 fuel line hookups not just one(2 port filter)
Its hooked directly to the fuel pump if you have a 2 port filter
It hooked to the 3rd port if you have a 3 port filter
FPR is set at 60psi pressure(+/-7psi), it uses a spring/valve setup, which are very reliable, but can break like anything else, just very rare
The pump can send out 80+psi, but can get weak
If you are only showing 40psi at the engine then it could be an FPR OR a Pump issue, but since they are BOTH part of a replacement assembly it doesn't matter, BOTH are replaced at the same time
This is assuming your Test Gauge is accurate, lol
Just make sure you get the correct assembly that has the 2 fuel line hookups not just one(2 port filter)
do you know a part number
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