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Username Post: Fuel Pressure Regulator        (Topic#358998)
Posts: 119

Reg: 10-27-16
11-30-19 09:22 PM - Post#2781315    

I've been pondering this and thought I would bounce it off you guys. In the GM TBI system, fuel pressure is not maintained after shutdown, it is allowed to bleed off quickly. If you have rebuilt these throttle bodies, you will know that fuel from the inlet goes directly to the injector BEFORE going on the the pressure regulator. From the regulator, fuel is returned to the tank. I always thought the regulator regulated the pump pressure down to the proper value. But I think I now understand that the regulator can only bump pressure up since it acts as a restrictor.

"8th Year" Silver Supporting Member
Posts: 4298
Loc: Salt Lake City
Reg: 06-20-09
11-30-19 11:06 PM - Post#2781318    
    In response to go_hercules

Correct. The pressure is created by the regulator and the needed 9+ psi gives the injectors the ability to deliver the appropriate volume. That’s why when the pressure is low, the spray pattern gets out of whack.


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Posts: 119

Reg: 10-27-16
12-01-19 04:24 PM - Post#2781343    
    In response to CowboyTrukr

Thank you for the info.

"6th Year" Gold Supporting Member
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Loc: Utica ny
Reg: 04-13-10
12-01-19 04:51 PM - Post#2781346    
    In response to go_hercules

Yup correct.
Nice Diagram

Old School GM fan FOREVER

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