Bad Fuel Pressure Regulator?
07-25-2012, 05:03 PM
#1
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Join Date: Jan 2012
Posts: 58
Bad Fuel Pressure Regulator?
Question:
1. If fuel is present in the vacuum hose of the FPR(Fuel Pressure Regulator), does this indicate a bad FPR?
2. Can someone confirm that the vacuum hose is the small hose on top of the FPR and the fuel hose is the larger hose on the bottom of the FPR?
3. Has anyone used the $30 EBAY adjustable FPR? How to hook it up and if it's worth it vs OE FPR $70.
When I disconnected the smaller hose on top of the FPR, fuel came out. I'm thinking this may be the culprit of the starting issue on my car that I've been troubleshooting for a while now.
1. If fuel is present in the vacuum hose of the FPR(Fuel Pressure Regulator), does this indicate a bad FPR?
2. Can someone confirm that the vacuum hose is the small hose on top of the FPR and the fuel hose is the larger hose on the bottom of the FPR?
3. Has anyone used the $30 EBAY adjustable FPR? How to hook it up and if it's worth it vs OE FPR $70.
When I disconnected the smaller hose on top of the FPR, fuel came out. I'm thinking this may be the culprit of the starting issue on my car that I've been troubleshooting for a while now.
Last edited by 2000_Maxima_SE; 07-25-2012 at 05:28 PM.
07-25-2012, 06:58 PM
#2
Question:
1. If fuel is present in the vacuum hose of the FPR(Fuel Pressure Regulator), does this indicate a bad FPR?
Correct!
2. Can someone confirm that the vacuum hose is the small hose on top of the FPR and the fuel hose is the larger hose on the bottom of the FPR?
Correct! Smaller hose is vacuum hose.
3. Has anyone used the $30 EBAY adjustable FPR? How to hook it up and if it's worth it vs OE FPR $70.
Have not tried ebay but replaced with OEM and it starts up even faster.
When I disconnected the smaller hose on top of the FPR, fuel came out. I'm thinking this may be the culprit of the starting issue on my car that I've been troubleshooting for a while now.
1. If fuel is present in the vacuum hose of the FPR(Fuel Pressure Regulator), does this indicate a bad FPR?
Correct!
2. Can someone confirm that the vacuum hose is the small hose on top of the FPR and the fuel hose is the larger hose on the bottom of the FPR?
Correct! Smaller hose is vacuum hose.
3. Has anyone used the $30 EBAY adjustable FPR? How to hook it up and if it's worth it vs OE FPR $70.
Have not tried ebay but replaced with OEM and it starts up even faster.
When I disconnected the smaller hose on top of the FPR, fuel came out. I'm thinking this may be the culprit of the starting issue on my car that I've been troubleshooting for a while now.
07-25-2012, 10:09 PM
#3
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Join Date: Jan 2012
Posts: 58
il. FPR is failing once fuel is in that vacuum line.
07-31-2012, 09:39 PM
#4
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Join Date: Jan 2012
Posts: 58
Today I replaced the fuel pressure regulator. Still no change. I'm still having trouble starting the car. I would have to step on the gas pedal a few times, not all the way though before it'll start. I checked the vacuum hose on the new fuel pressure regulator and old fuel pressure damper and they both have fuel in them!!! 
I suspect fuel in the vacuum line is why I have to step on the gas pedal to get it to start?
I'm stomped once again. Could my problem be a bad fuel pressure damper?
I suspect fuel in the vacuum line is why I have to step on the gas pedal to get it to start? I'm stomped once again. Could my problem be a bad fuel pressure damper?
08-01-2012, 01:38 PM
#5
Makes no sense to me why fuel is still in there. Disconnec the vacuum hose and have someone turn the key to ON and see if it is still leaking fuel. Where did you get the FPR? Also when you start the car from cold in the morning, where does the RPM needle go to? Number reading here...
08-02-2012, 11:23 PM
#6
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Makes no sense to me why fuel is still in there. Disconnec the vacuum hose and have someone turn the key to ON and see if it is still leaking fuel. Where did you get the FPR? Also when you start the car from cold in the morning, where does the RPM needle go to? Number reading here...
08-05-2012, 07:07 AM
#9
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Here are the results checking for fuel in the vacuum line again for the FPR and the FPR Damper:
FPR - Not a lot but very small droplets of fuel comes out.
FPR Damper - Fuel just keeps coming out.
I'll try and record a video of this for you guys later.
FPR - Not a lot but very small droplets of fuel comes out.
FPR Damper - Fuel just keeps coming out.
I'll try and record a video of this for you guys later.
08-05-2012, 07:17 AM
#10
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Join Date: Jan 2012
Posts: 58
The cam sensor resistance checked out good. I replaced one of the crank sensor (REF, the one by the crank pulley) already. A fellow org. member said the resistance of the crank sensor should change if a magnetic item was by it. The front crank sensor showed no change of resistance when I tested it with my multimeter. I will be replacing that one soon.
I don't see how the Cam or Crank sensors have anything to do with fuel in the vacuum line. Only starting issues...
I don't see how the Cam or Crank sensors have anything to do with fuel in the vacuum line. Only starting issues...
Last edited by 2000_Maxima_SE; 08-05-2012 at 07:19 AM.
08-07-2012, 05:31 AM
#11
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Join Date: Jan 2012
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Here is the youtube link to my video showing the problem.
http://www.youtube.com/watch?v=myeMe...ature=youtu.be
http://www.youtube.com/watch?v=myeMe...ature=youtu.be
08-07-2012, 07:16 AM
#12
I could be wrong but I do not think you should have fuel coming out of the fuel damper vacuum line(like at all and yours is consistent). You may want to check the other vacuum line as well because I noticed one drip off the FPR when you first tried to start the car. So you may still have fuel in that vacuum line as well(did it cut off when you plugged this line back in or did someone shut off the car?). I'd wait for others to confirm you need a new fuel damper but I can't confirm of deny its your starting issue.
08-07-2012, 09:27 PM
#13
The cam sensor resistance checked out good. I replaced one of the crank sensor (REF, the one by the crank pulley) already. A fellow org. member said the resistance of the crank sensor should change if a magnetic item was by it. The front crank sensor showed no change of resistance when I tested it with my multimeter. I will be replacing that one soon.
I don't see how the Cam or Crank sensors have anything to do with fuel in the vacuum line. Only starting issues...
I don't see how the Cam or Crank sensors have anything to do with fuel in the vacuum line. Only starting issues...
Last edited by Max_5gen; 08-07-2012 at 09:36 PM.
08-08-2012, 01:10 AM
#14
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Join Date: Jan 2012
Posts: 58
I could be wrong but I do not think you should have fuel coming out of the fuel damper vacuum line(like at all and yours is consistent). You may want to check the other vacuum line as well because I noticed one drip off the FPR when you first tried to start the car. So you may still have fuel in that vacuum line as well(did it cut off when you plugged this line back in or did someone shut off the car?). I'd wait for others to confirm you need a new fuel damper but I can't confirm of deny its your starting issue.
08-08-2012, 08:22 AM
#15
Member
Join Date: Oct 2004
Posts: 175
Unfortunately you have another defective unit bud. Your beck/arney regulator needs to get returned.
I would buy an OEM unit if it were me. If ANY fuel ever comes out then your diaphragm is compromised period. It can also be leaking the other way and bypassing too much fuel in back to the return. The quick test are some vise grips gently squeezing the return line to falsely "limit" the return fuel and bumping up pressure. If that helps your starting condition then you have your answer - you could have it both ways.
When you plug the vacuum line back in (at idle) it will cause a lean out. The vaccum the engine produces at idle keeps your pressure lower as the diaphragm is controlled directly by that vacuum line (which should be completely cleaned/cleared out before the next regulator goes in). I'm not sure if you're having any other associated issues with your ride, but good job coming to the regulator for your hard start. If it leaks there it is bad, bummer you got a new defective part but it does happen - and often times confuses folks that trust in a new part simply because it is new.
I would get an OEM unit, clean out all the fuel you can and then report back. Any trace amounts of fuel in the intake manifold will evaporate and/or burn out soon enough.
I would buy an OEM unit if it were me. If ANY fuel ever comes out then your diaphragm is compromised period. It can also be leaking the other way and bypassing too much fuel in back to the return. The quick test are some vise grips gently squeezing the return line to falsely "limit" the return fuel and bumping up pressure. If that helps your starting condition then you have your answer - you could have it both ways.
When you plug the vacuum line back in (at idle) it will cause a lean out. The vaccum the engine produces at idle keeps your pressure lower as the diaphragm is controlled directly by that vacuum line (which should be completely cleaned/cleared out before the next regulator goes in). I'm not sure if you're having any other associated issues with your ride, but good job coming to the regulator for your hard start. If it leaks there it is bad, bummer you got a new defective part but it does happen - and often times confuses folks that trust in a new part simply because it is new.
I would get an OEM unit, clean out all the fuel you can and then report back. Any trace amounts of fuel in the intake manifold will evaporate and/or burn out soon enough.
Last edited by noahrexion; 08-08-2012 at 08:25 AM.
08-08-2012, 08:25 AM
#16
its a large chance it is clogged, because before you hooked up that vacuum line it was running fine.
08-09-2012, 01:40 AM
#17
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Join Date: Jan 2012
Posts: 58
Unfortunately you have another defective unit bud. Your beck/arney regulator needs to get returned.
I would buy an OEM unit if it were me. If ANY fuel ever comes out then your diaphragm is compromised period. It can also be leaking the other way and bypassing too much fuel in back to the return. The quick test are some vise grips gently squeezing the return line to falsely "limit" the return fuel and bumping up pressure. If that helps your starting condition then you have your answer - you could have it both ways.
When you plug the vacuum line back in (at idle) it will cause a lean out. The vaccum the engine produces at idle keeps your pressure lower as the diaphragm is controlled directly by that vacuum line (which should be completely cleaned/cleared out before the next regulator goes in). I'm not sure if you're having any other associated issues with your ride, but good job coming to the regulator for your hard start. If it leaks there it is bad, bummer you got a new defective part but it does happen - and often times confuses folks that trust in a new part simply because it is new.
I would get an OEM unit, clean out all the fuel you can and then report back. Any trace amounts of fuel in the intake manifold will evaporate and/or burn out soon enough.
I would buy an OEM unit if it were me. If ANY fuel ever comes out then your diaphragm is compromised period. It can also be leaking the other way and bypassing too much fuel in back to the return. The quick test are some vise grips gently squeezing the return line to falsely "limit" the return fuel and bumping up pressure. If that helps your starting condition then you have your answer - you could have it both ways.
When you plug the vacuum line back in (at idle) it will cause a lean out. The vaccum the engine produces at idle keeps your pressure lower as the diaphragm is controlled directly by that vacuum line (which should be completely cleaned/cleared out before the next regulator goes in). I'm not sure if you're having any other associated issues with your ride, but good job coming to the regulator for your hard start. If it leaks there it is bad, bummer you got a new defective part but it does happen - and often times confuses folks that trust in a new part simply because it is new.
I would get an OEM unit, clean out all the fuel you can and then report back. Any trace amounts of fuel in the intake manifold will evaporate and/or burn out soon enough.
08-09-2012, 07:50 AM
#18
Member
Join Date: Oct 2004
Posts: 175
Yes of course, if fuel is coming out (of either) of the vaccum port it is bad, needs replacing .
The damper actually helps the regulator maintain (constant/smooth) pressure by damping fuel pump/injector pulses - they work in unison but almost in an identical way. Both have that vacuum operated diaphram atop that fuel should never be leaking past.
The damper actually helps the regulator maintain (constant/smooth) pressure by damping fuel pump/injector pulses - they work in unison but almost in an identical way. Both have that vacuum operated diaphram atop that fuel should never be leaking past.
08-23-2012, 10:41 PM
#19
Junior Member
Join Date: May 2009
Posts: 62
Well, what da heck happened? LOL - I have a similar problem with my mom's Maxima that I need to resolve. Did you replace both parts and it started working? If not, what was the fix? PLEASE POST BACK SOON!! 
FYI - I have posted a thread over here:
http://x.nissanhelp.com/forums/maxim...html#post81719 ... if you'd like to chime in.
FYI - I have posted a thread over here:
http://x.nissanhelp.com/forums/maxim...html#post81719 ... if you'd like to chime in.
08-28-2012, 07:52 PM
#21
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Join Date: Jan 2012
Posts: 58
Summary
Here's the summary of my thread:
My problem: The Maxima has a hard time starting. In most cases, I would have to step on the gas at the same time when starting the ignition for it to run. Once it started running, I have to keep the rpm constant at 1K-1.5K RPM for 2-5 seconds before it has a stable idle. There is no performance loss after the car has successfully started.
How to troubleshoot:
- This requires two people and one if you have remote start. Disconnect the Vacuum line of the Fuel Pressure Regulator AND Fuel Pressure Damper and check for fuel. There should be NO fuel present in the Vacuum lines or Vacuum port of the Fuel Pressure Regulator and Fuel Pressure Damper.
- Total Diagnostic time: 5-10 minutes.
- Difficulty: EASY
The solution:
- A New O.E. Fuel Pressure Regulator ($70-$120 on EBAY)
- A New O.E. Fuel Pressure Damper ($115-$150 on EBAY)
** Anyone with basic mechanical skills should be able to replace these parts in 2-4 hours. It's VERY IMPORTANT when dealing anything fuel related on the car to relieve all the fuel pressure out by removing the 15 AMP Fuel Pump fuse in the fuse box under the dash of the driver side, removing the fuel cap, and starting the car until it can't start anymore. **
Tools needed for this job:
- 10mm socket with ratchet
- Socket extension
- Flathead screwdriver
- Pliers
The Fuel Pressure Regulator and Damper is fairly easy to replace.
1. Remove Air Intake.
2. For the Fuel Pressure Regulator, remove the two 10mm bolts on it. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure Regulator.
3. For the Fuel Pressure Damper, there are a total of 5 10mm bolts you have to remove. Two on the Damper, one on the bracket in the middle of the damper hose, and two at the end of the damper hose. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure
**Make sure there is an O-Ring on the Fuel Pressure Regulator and Damper or else Fuel will be everywhere when you attempt to start the car**
I hope this thread is helpful to anyone who is having similar problems on their Maximas. GODSPEED
My problem: The Maxima has a hard time starting. In most cases, I would have to step on the gas at the same time when starting the ignition for it to run. Once it started running, I have to keep the rpm constant at 1K-1.5K RPM for 2-5 seconds before it has a stable idle. There is no performance loss after the car has successfully started.
How to troubleshoot:
- This requires two people and one if you have remote start. Disconnect the Vacuum line of the Fuel Pressure Regulator AND Fuel Pressure Damper and check for fuel. There should be NO fuel present in the Vacuum lines or Vacuum port of the Fuel Pressure Regulator and Fuel Pressure Damper.
- Total Diagnostic time: 5-10 minutes.
- Difficulty: EASY
The solution:
- A New O.E. Fuel Pressure Regulator ($70-$120 on EBAY)
- A New O.E. Fuel Pressure Damper ($115-$150 on EBAY)
** Anyone with basic mechanical skills should be able to replace these parts in 2-4 hours. It's VERY IMPORTANT when dealing anything fuel related on the car to relieve all the fuel pressure out by removing the 15 AMP Fuel Pump fuse in the fuse box under the dash of the driver side, removing the fuel cap, and starting the car until it can't start anymore. **
Tools needed for this job:
- 10mm socket with ratchet
- Socket extension
- Flathead screwdriver
- Pliers
The Fuel Pressure Regulator and Damper is fairly easy to replace.
1. Remove Air Intake.
2. For the Fuel Pressure Regulator, remove the two 10mm bolts on it. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure Regulator.
3. For the Fuel Pressure Damper, there are a total of 5 10mm bolts you have to remove. Two on the Damper, one on the bracket in the middle of the damper hose, and two at the end of the damper hose. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure
**Make sure there is an O-Ring on the Fuel Pressure Regulator and Damper or else Fuel will be everywhere when you attempt to start the car**
I hope this thread is helpful to anyone who is having similar problems on their Maximas. GODSPEED
Last edited by 2000_Maxima_SE; 08-28-2012 at 08:27 PM.
12-22-2012, 06:12 PM
#24
Newbie - Just Registered
Join Date: Dec 2012
Posts: 7
Here's the summary of my thread:
My problem: The Maxima has a hard time starting. In most cases, I would have to step on the gas at the same time when starting the ignition for it to run. Once it started running, I have to keep the rpm constant at 1K-1.5K RPM for 2-5 seconds before it has a stable idle. There is no performance loss after the car has successfully started.
How to troubleshoot:
- This requires two people and one if you have remote start. Disconnect the Vacuum line of the Fuel Pressure Regulator AND Fuel Pressure Damper and check for fuel. There should be NO fuel present in the Vacuum lines or Vacuum port of the Fuel Pressure Regulator and Fuel Pressure Damper.
- Total Diagnostic time: 5-10 minutes.
- Difficulty: EASY
The solution:
- A New O.E. Fuel Pressure Regulator ($70-$120 on EBAY)
- A New O.E. Fuel Pressure Damper ($115-$150 on EBAY)
** Anyone with basic mechanical skills should be able to replace these parts in 2-4 hours. It's VERY IMPORTANT when dealing anything fuel related on the car to relieve all the fuel pressure out by removing the 15 AMP Fuel Pump fuse in the fuse box under the dash of the driver side, removing the fuel cap, and starting the car until it can't start anymore. **
Tools needed for this job:
- 10mm socket with ratchet
- Socket extension
- Flathead screwdriver
- Pliers
The Fuel Pressure Regulator and Damper is fairly easy to replace.
1. Remove Air Intake.
2. For the Fuel Pressure Regulator, remove the two 10mm bolts on it. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure Regulator.
3. For the Fuel Pressure Damper, there are a total of 5 10mm bolts you have to remove. Two on the Damper, one on the bracket in the middle of the damper hose, and two at the end of the damper hose. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure
**Make sure there is an O-Ring on the Fuel Pressure Regulator and Damper or else Fuel will be everywhere when you attempt to start the car**
I hope this thread is helpful to anyone who is having similar problems on their Maximas. GODSPEED
My problem: The Maxima has a hard time starting. In most cases, I would have to step on the gas at the same time when starting the ignition for it to run. Once it started running, I have to keep the rpm constant at 1K-1.5K RPM for 2-5 seconds before it has a stable idle. There is no performance loss after the car has successfully started.
How to troubleshoot:
- This requires two people and one if you have remote start. Disconnect the Vacuum line of the Fuel Pressure Regulator AND Fuel Pressure Damper and check for fuel. There should be NO fuel present in the Vacuum lines or Vacuum port of the Fuel Pressure Regulator and Fuel Pressure Damper.
- Total Diagnostic time: 5-10 minutes.
- Difficulty: EASY
The solution:
- A New O.E. Fuel Pressure Regulator ($70-$120 on EBAY)
- A New O.E. Fuel Pressure Damper ($115-$150 on EBAY)
** Anyone with basic mechanical skills should be able to replace these parts in 2-4 hours. It's VERY IMPORTANT when dealing anything fuel related on the car to relieve all the fuel pressure out by removing the 15 AMP Fuel Pump fuse in the fuse box under the dash of the driver side, removing the fuel cap, and starting the car until it can't start anymore. **
Tools needed for this job:
- 10mm socket with ratchet
- Socket extension
- Flathead screwdriver
- Pliers
The Fuel Pressure Regulator and Damper is fairly easy to replace.
1. Remove Air Intake.
2. For the Fuel Pressure Regulator, remove the two 10mm bolts on it. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure Regulator.
3. For the Fuel Pressure Damper, there are a total of 5 10mm bolts you have to remove. Two on the Damper, one on the bracket in the middle of the damper hose, and two at the end of the damper hose. Use pliers to move the clamp down on fuel hose. Then CAREFULLY use a flathead screwdriver to pry off the the fuel hose and vacuum hose on the Fuel Pressure
**Make sure there is an O-Ring on the Fuel Pressure Regulator and Damper or else Fuel will be everywhere when you attempt to start the car**
I hope this thread is helpful to anyone who is having similar problems on their Maximas. GODSPEED
12-22-2012, 09:20 PM
#26
Newbie - Just Registered
Join Date: Dec 2012
Posts: 7
Hi One more question is there a fuel pressure damper in 4th gen nissan maxima ??? I have a 1998 and I do not find a fuel pressure damper. I also tried to refer to my Haynes manual and it looks likes in 4th gen we do not have one can any one confirm me.
Thanks a lot
Thanks a lot
12-11-2013, 06:15 PM
#27
Member
Join Date: Aug 2011
Location: Jacksonville, FL
Posts: 106
Sorry to dredge this one up but I have a question concerning this and did not want to start another hard start thread. I have been having an extending cranking issue for the past few weeks. I just pulled my vac lines to troubleshoot and there is fuel pouring out of the fuel damper. I am confident this is the cause to my extended cranking BUT I have another issue and would like some opinions as to whether it is related or not.
In addition to extended cranking I'm also have a bad misfire that is more present at lower rpms. If I let it sit at idle it will get progressively worse until it starts to cut out. Could it be that my damper/fpr is so blown that it is causing a dead cylinder condition? Or is it likely I've fouled my plugs by now with the extremely excessive amount of fuel going into the engine? If i pull the vacuum line from the damper with the car off it will have a steady stream of fuel coming out until it empties. I can go check resistances on my CKPS's but I think it would be highly coincidental for one of them to go out in rapid succession after the damper. The misfire came a few days after the extended cranking started.
Any feedback on this would be greatly appreciated. Again my apologies for pulling up a year old thread but it seemed most relevant.
Edit: Forgot to mention I put the car on a Snap On Modis Diagnostic tool. Only codes were for multiple cylinder missing and cyl 5 misfire. Replacing that coil pack made no difference. Unplugging the other coil packs made the car run worse.
In addition to extended cranking I'm also have a bad misfire that is more present at lower rpms. If I let it sit at idle it will get progressively worse until it starts to cut out. Could it be that my damper/fpr is so blown that it is causing a dead cylinder condition? Or is it likely I've fouled my plugs by now with the extremely excessive amount of fuel going into the engine? If i pull the vacuum line from the damper with the car off it will have a steady stream of fuel coming out until it empties. I can go check resistances on my CKPS's but I think it would be highly coincidental for one of them to go out in rapid succession after the damper. The misfire came a few days after the extended cranking started.
Any feedback on this would be greatly appreciated. Again my apologies for pulling up a year old thread but it seemed most relevant.
Edit: Forgot to mention I put the car on a Snap On Modis Diagnostic tool. Only codes were for multiple cylinder missing and cyl 5 misfire. Replacing that coil pack made no difference. Unplugging the other coil packs made the car run worse.
Last edited by 5th gen dd; 12-11-2013 at 08:10 PM.
12-11-2013, 09:56 PM
#28
I'm hoping when you say "fuel damper"you really mean fuel pressure regulator. Because a fuel damper will always have fuel at all Ports. If it is the FPR you are refererring to, I suggest you change it first and see what happens. Fuel pressure that is way off will cause misfires and all kinds of problems.
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