Fuel pump constantly primes

Tiny
PUMRYSH
  • MEMBER
  • 1999 BUICK PARK AVENUE
  • 130,000 MILES
Noticed the fuel pump intermittently priming during my travel. Have changed the fuel pump along with the pressure switch, the fuel cap, fuel filter and fuel pressure regulator valve. The fuel pressure at the injector rail is 42psi at idle. I'm missing something but don't know what.
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Monday, October 10th, 2011 AT 4:27 AM

7 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
The pump should be running the entire time the engine is on. Is that what you mean? The regulator maintains a certain pressure at the fuel rail and additional fuel is pumpped back to the tank.

If it is something different, the relay could be going bad.
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Monday, October 10th, 2011 AT 4:29 AM
Tiny
PUMRYSH
  • MEMBER
Thanks Jacob,

The noise I hear is the priming noise that usually occurs when you first turn the key on. That noise will normally stop after the engine is fired. In my car it will reoccur as I travel.
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Monday, October 10th, 2011 AT 5:36 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
That is odd because the pump should stay on the entire time the engine is running. Could it be that you now can hear the pump but only hear it when it gets quiet? I know that question is most likely going to frustrate you, but like I said, if the pump was turning off and then repriming, the engine would lose power or stall.
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Monday, October 10th, 2011 AT 5:41 AM
Tiny
PUMRYSH
  • MEMBER
It is normal for a prime to occur at startup then a normal run condition occurs afterwards. Yes, the pump is always on but not in prime mode. Your idea about the relay being bad actually makes a lot of sense and is one that I will follow up on today.
Thanks!
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Monday, October 10th, 2011 AT 8:06 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
It is normal for the prime at start up to re-pressurize the system. Once pressurized, the system should just maintain a specific pressure.
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Monday, October 10th, 2011 AT 4:21 PM
Tiny
PUMRYSH
  • MEMBER
Just wanted to let you know that I replaced the Fuel Pump Relay and the problem now seems to be fixed. The pump primes at startup and then runs quietly for the rest of my drive.

Thanks for your help!
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Wednesday, October 12th, 2011 AT 2:01 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Great! Glad you got it taken care of.
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Wednesday, October 12th, 2011 AT 2:33 AM

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