The fuel pressure regulator is leaking gas

Tiny
JASONROYCESHANNON420
  • MEMBER
  • 2004 CHEVROLET CAVALIER
  • 2.2L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 112,638 MILES
I've been smelling gas from the front of my car for about 4 weeks now. Finally found out where the problem is. The fuel pressure regulator is leaking gas and it is causing my gas mileage to be very low. I know I need to relieve the fuel pressure, therefore I would need to locate the fuel pump relay and disconnect it. Now my problem is finding a better description on exactly where it would be, because I cant read schematics to well. So where would this be located?
Sunday, November 24th, 2013 AT 12:11 AM

16 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,870 POSTS
Every service manual describes how to relieve fuel pressure but we rarely do that. When customers are paying us by the hour, we don't have time to spend on things like that. There isn't that much fuel that's going to spray out, especially when the regulator is already leaking. The same is true when replacing fuel filters. We just pop a hose off and let the fuel run on the ground. You'll only get a few tablespoons. You can also look for a fuel pump fuse. Remove it, then try to start the engine. You can also look for a pressure test port on the fuel rail and use that to bleed off the pressure. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.
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Sunday, November 24th, 2013 AT 2:16 AM
Tiny
LIINDA05
  • MEMBER
  • 1 POST
  • 2001 CHEVROLET CAVALIER
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 170,011 MILES
Where can I find the fuel pressure regulator and how do I check to see if is working properly?
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
BRIAN 1
  • MECHANIC
  • 1,030 POSTS
The fuel pressure regulator is located at the end of the fuel rail with the fuel injectors. It will have a vacuum line attached to it. If you want to check it install a fuel pressure gauge see what the pressure is at running(53-59psi) unplug the vacuum line and if it is working the pressure should increase 3-5 psi. That means its working. Or test it with a vacuum pump, apply 12-14 in of vacuum, should hold vacuum. Post back with any other questions.
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
  • 1999 CHEVROLET CAVALIER
  • 21,000 MILES
How can I remove the screw from the brackets the bottom) on the fuel pressure regulator. I am attempting to change or replace the fuel pressure regulator. I have already removed the side torx screw attached to the bracket.
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Relieve the fuel system pressure.
Disconnect the negative battery cable.
Remove the vacuum hose from the regulator.
Place a rag under the connection and remove the fuel return pipe clamp.
Remove the fuel return pipe and O-ring from the regulator. Discard the O-ring.
Unfasten the pressure regulator bracket attaching screw, then remove the pressure regulator assembly and O-ring. Discard the O-ring.
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
ICYMBY
  • MEMBER
  • 7 POSTS
  • 1990 CHEVROLET CAVALIER
  • 2.2L
  • 4 CYL
  • 2WD
  • MANUAL
  • 120,000 MILES
I cannot seem to find an exact diagram for this engine, it’s the TBI so I don’t know if it’s the throttle body itself or what! Any help is much appreciated!
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

In the diagrams down below I have included the description of operation and the instructions for the removal and installation of your vehicle's fuel pressure regulator[including a diagram of it's location] from the vehicle manufacturer for you. Please go through this guide and get back to us with how everything turns out, and I hope that this helps out.

Thanks,
Alex
2CarPros
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
ICYMBY
  • MEMBER
  • 7 POSTS
Thank you that was exactly was we needed. We changed the FPR and the plugs so it runs now. But after it gets warm it will start to bog out and die. Once it dies, you basically have to unplug the injector, clear it out, plug it back in, and it will start. Did we drop an injector? Or is something clogged. Before we couldn’t get it to run at all. Runs very rich.
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Please check the o-rings that seal the injectors. This could be a possibility that one is leaking and letting fuel leak into the throttle body that way. Also, has the vehicle been in service or has it been sitting for a while?

Thanks,
Alex
2CarPros
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
ICYMBY
  • MEMBER
  • 7 POSTS
I’ll give the o-rings a look over. It has been sitting for about 3 months and I took delivery of the vehicle 4 days ago and it ran for a solid 30 minutes before the everything went to heck. Appreciate all of the help so far thank you!
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
ICYMBY
  • MEMBER
  • 7 POSTS
Got time to replace the injector finally. Once we got it started and cleared out a bit, it ran really good. Drove it around for about 45 minutes with no issues. After that and it became idling for a few minutes, it started to have a “surge” again when you hit the pedal. Now, it shut off a few times, but started right back up instantly with either no pedal action or just a hair. Before replacing the injector and it shut off, you were basically stuck because it was going to start back up. I’m going to go do the fuel filter today as they had to order one in when I did the injector, so I’m hoping it would be that but any other thoughts? Thanks for all the help so far.
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
ICYMBY
  • MEMBER
  • 7 POSTS
Also, I should say it’s still running really rich, so 02 sensor maybe? I’ve changed out the plugs already.
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

This sounds like either an electrical problem or it could be an intake/vacuum leak. Let's start with the latter. If this was an intake/vacuum leak then it would be letting unmetered air into the air intake system. Unmetered air is defined as air that enters the air intake system from the Mass AirFlow sensor[MAF] to the combustion chambers of the engine. The Power-train Control Module[PCM] will get a lean signal from the O2 sensors and will over adjust for this by holding open the fuel injectors longer causing a rich condition. Here is a link below explaining how to find a intake/vacuum leak below:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please go through this guide and get back to us with what you find out.

Thanks,
Alex
2CarPros
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
ICYMBY
  • MEMBER
  • 7 POSTS
Went through all the vacuum lines and they seemed just fine. I noticed cylinder 4 spark plug wire wasn’t snapping on so I pulled it off and it ran the same for the most part. I’m not going to rule it to that but I ordered new wires and another set of plugs. The car is running now, and when it dies, it’ll start right back up with the right amount of pedal action following a pretty good rough idle where it takes about 10 seconds to clear up. Still noticing the problem after it starts to get warmer. My plumbed in water temperature reads around 110 ish about when it starts to really take a dive on me.
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

I'm 99.9% sure that you've found your problem. The PCM will still fire that fuel injector and without a spark plug to ignite it, the air:fuel mixture will get shot out of the exhaust and the O2 sensor will read it as being rich. It will cut fuel to the other injectors causing them to run lean and it will affect performance. I would suggest unplugging the fuel injector connector from the problem cylinder until the new spark plug wires arrive. It will make no difference as it is a dead cylinder anyway, the short and long fuel trim will normalize and you will save gas. Please keep us informed as to how everything turns out.

Thanks,
Alex
2CarPros
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Wednesday, May 12th, 2021 AT 7:01 PM (Merged)
Tiny
ICYMBY
  • MEMBER
  • 7 POSTS
Well it’s the TBI so only one injector, just a beater car so it’s parked. I will let you know what the result, I also ordered an 02 sensor as it was only $8 so I’ll change that out too in case any fouling happened.
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Wednesday, May 12th, 2021 AT 7:02 PM (Merged)

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