1991 Toyota Corolla Fuel Pumps

Tiny
NINOGERMANA
  • MEMBER
  • 1991 TOYOTA COROLLA
  • 4 CYL
  • FWD
  • AUTOMATIC
What is the dfference between a 40-GPH fuel Pump and A 120-GPH fuel pump, and how does the difference between the two affect performance, and miles per gallon? Or efficiency/ fuel economy
Tuesday, December 30th, 2008 AT 6:36 PM

1 Reply

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
One pumps more volume of fuel than the other. The real question is fuel pressure. If the 120 unit produces higher than normal fuel pressure (say 60psi vs the stock 40-45psi) then engine will run rich and the ECM will try to remove fuel from engine by reducing injector pulse timing. But you can only reduce the pulse so much.
The 120 unit may pump so much volume that the FPR cannot bypass enough back to tank causing the increase in fuel pressure.
High fuel presure can damage the injectors and supply/return lines to fuel rail.
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Tuesday, March 2nd, 2021 AT 9:29 AM

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