Fuel pressure regulator

Tiny
PATW54
  • MEMBER
  • 1996 GMC JIMMY
  • 4.3L
  • V6
  • 4WD
  • AUTOMATIC
  • 185,000 MILES
Put new regulator in and now popping through carburator. Won't start. Not showing any pressure on regulator test either. Do I need to replace fuel pump?
Wednesday, October 16th, 2019 AT 12:17 AM

3 Replies

Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

It has been my experience that fuel pumps either work or they don't. A quick way to test to see if your fuel pump is working is to have a helper turn the ignition key to "run" while you have an ear back at the fuel tank. The fuel pump should come on for a couple of seconds to prime the system. If the fuel pump is okay then I would double check the vacuum line attached to the fuel pressure regulator and make sure that it is okay and not leaking. Also, check to see if any fuel is in the vacuum line, as this would indicate that the fuel pressure regulator has a bad diaphragm. Please get back to us with what you are able to find out and we can go from there.

Thanks,
Alex
2CarPros
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Wednesday, October 16th, 2019 AT 4:13 AM
Tiny
PATW54
  • MEMBER
  • 15 POSTS
When I took the regulator off I didn't see any vacuum line attached to it. So where is this vacuum line? My manual does not show any vacuum line.
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Wednesday, October 16th, 2019 AT 9:28 AM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

The fuel pressure regulator is controlled by engine vacuum. If there was not a vacuum line attached to the regulator that was in your vehicle, that was probably the problem. I would definitely try to locate the vacuum line or you will have a major vacuum leak which will cause any sort of idle and driveability problems. Just follow all the vacuum lines around the engine, they should all originate from the throttle body and you will come across it. If not, you can pick up vacuum line and T fittings at any auto part store. Just cut the vacuum line anywhere, insert a T fitting, and then run vacuum line to the fuel pressure regulator. In the diagrams down below I have included the instructions for the removal and installation of the fuel pressure regulator from the vehicle manufacturer. Please go through this guide and get back to us with what you find out.

Thanks,
Alex
2CarPros
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Wednesday, October 16th, 2019 AT 12:35 PM

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