1999 GMC Sierra Fuel Pump/relay

1999 GMC SIERRA
206,800 MILES • V8 • 4WD • AUTOMATIC
Avatar
ADSMTZ
  • MEMBER
  • 3 POSTS
I have read a lot of fuel pump questions. My problem for about 8 months.

I turn the key on, motor turns over fine.
I have to turn the key off and start it again. (Kind of like the old diesel motors with glo plugs). I hear a clicking and the fuel rail pressuarize and it fires right up. I have changed every relay under the hood, side panel and by the brake pedal.

changed the spark plugs (new style)
changed fuel pressure regulator
Checked Map sensor and O2 sensor

No codes, It runs great when it starts. Been like that for a while.

Should I check with fuel pressure gauge.
Jun 21, 2010 at 5:55 PM
Advertisement
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
When the fuel pressure checks out test the ignition switch
Jun 21, 2010 at 6:04 PM
Avatar
ADSMTZ
  • MEMBER
  • 3 POSTS
The first time it was only 25 psi.
Cycle the key it got up to 34 or so.
Third time I cycled up to 55 psi
Everytime after that it was 60 plus.

It seems to drain or lose prime after it sits for 10 minutes or so. I have to cycle through the keys to get the pressure up.

After it starts, it does not hessitate or give me any problems on the road.

New Fuel Filter and Fuel Pressure regulator relaced as well as all new relays.

Is this my fuel pump?
Jun 27, 2010 at 10:27 PM
Advertisement
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
Could be the injector/s or the fuel pump check valve leaking that you losing the residual pressure
Jun 28, 2010 at 11:39 AM
Avatar
ADSMTZ
  • MEMBER
  • 3 POSTS
How do I find the bad injector(s)?


Never heard of the check leak valve from the fuel pump. Is it a replacement part?

Thanks...for your response.

I have a Chilton book, I will look it up.
Jun 28, 2010 at 4:43 PM