Fuel pressure regulator installation

Tiny
DOUG42190
  • MEMBER
  • 1995 CHEVROLET CAMARO
  • 3.4L
  • V6
  • 2WD
  • AUTOMATIC
  • 159,000 MILES
You guys have helped me tremendously over the course of these repairs, thank you.
Is it possible to install a fuel pressure regulator incorrectly? I have hunted high and low to find a picture or text on how it goes in. I do not remember what it looked like when I put my new one in (the fuel rail location) but I have a fuel pressure problem. KOEOff I get 70 PSI of fuel pressure measured at the "out" side of the fuel filter and at the supply line quick disconnect at the engine. The problem is I only get 30 PSI out of the fuel rail schrader valve. Vacuum line connected or disconnected and a slight drop engine running. I am in the process of pulling the plenum/fuel rail back off and look for a crimped metal fuel supply line or an obstruction in the fuel rail somewhere. I am going to check the fuel pressure regulator, but I want to make sure I know what I am looking at. Install pictures or diagram would be great.
Thank you,
Doug
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Wednesday, September 12th, 2018 AT 9:38 AM

12 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good morning.

70 lbs at the fuel filter is not bad. That is called dead head pressure or unregulated.

Checking it at the schraeder valve is the actual pressure using the regulator.

The pressure should be 41-47 lbs.

The fuel pressure regulator and fuel rail are serviced as a complete assembly only. Do not attempt to remove the regulator cover from the fuel rail. Even though some people sell the regulators, I would not replace it.

Roy
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Wednesday, September 12th, 2018 AT 10:22 AM
Tiny
PATENTED_REPAIR_PRO
  • EXPERT
Here are the instructions. Note: On 3.4L, fuel pressure regulator and fuel rail are serviced as an assembly only. Do not remove pressure regulator or pressure regulator cover from fuel rail.
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Wednesday, September 12th, 2018 AT 10:25 AM
Tiny
DOUG42190
  • MEMBER
I read that they should not be serviced separately. I am able to find the regulator but I am not able to find the fuel rail/separator as a unit. I guess I am stuck just replacing the regulator. Car is twenty three years old and new parts are real scarce.
Any ideas as to what that white powdery substance might be? The regulator is only five or six weeks old and that was not there when I changed it.
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Wednesday, September 12th, 2018 AT 11:21 AM
Tiny
DOUG42190
  • MEMBER
Any suggestions as to things beside an obstruction or bent metal fuel line I should look for?
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Wednesday, September 12th, 2018 AT 11:22 AM
Tiny
ASEMASTER6371
  • EXPERT
Do not think you have either. If you did, your dead head pressure would be low.

Try calling the dealer and ask them for any new old stock. They can research the part number for you.

Roy
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Wednesday, September 12th, 2018 AT 11:32 AM
Tiny
DOUG42190
  • MEMBER
What about the metal supply line that attaches to the plenum and makes a u-turn and goes into the fuel rail itself? I cannot detect anything other than a smooth curve, no kinks or flat spots. That leaves the fuel rail, thoughts about an obstruction in the rail it self? I blew carburetor cleaner from the supply and return lines into the fuel rail which quickly came out of the ports where the FPR resides. I also took the valve stem out of the schrader valve and blew carburetor cleaner into it. Any other suggestions? Would blocking off the return line and then check the pressure at the schrader tell us anything?
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Wednesday, September 12th, 2018 AT 12:50 PM
Tiny
DOUG42190
  • MEMBER
One other question: In the pictures I sent there are three parts; the diaphragm, the housing, and this washer looking thing. The washer has a raised lip on the inside of the hole. Does that lip "trap" the diaphragm against the housing or does the lip face away from the rubber diaphragm?
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Wednesday, September 12th, 2018 AT 12:56 PM
Tiny
ASEMASTER6371
  • EXPERT
No to the rail pressure test. If you block off the return, you should have the same pressure you had at the filter.

It appears to be that way with the lip.

Roy
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Wednesday, September 12th, 2018 AT 1:46 PM
Tiny
DOUG42190
  • MEMBER
So the lip "traps" the diaphragm against the housing?
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Wednesday, September 12th, 2018 AT 2:01 PM
Tiny
ASEMASTER6371
  • EXPERT
Looks to be that way. I have never had one apart. I always did the rail.

Roy
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Wednesday, September 12th, 2018 AT 2:06 PM
Tiny
DOUG42190
  • MEMBER
Well, I finally got it. The order of assembly seems to be diaphragm, then housing, and then the "washer" goes over the housing. Therefore the bolts go through the "washer, " through the housing, through the diaphragm and then screw into the fuel rail. Pressure went from 30 to 43 psi.
Thanks for all your help.
Doug
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Wednesday, September 12th, 2018 AT 6:02 PM
Tiny
ASEMASTER6371
  • EXPERT
You are welcome.

We are always glad to help.

Roy
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Wednesday, September 12th, 2018 AT 6:08 PM

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