1991 Toyota Corolla Fuel Pumps

1991 TOYOTA COROLLA
4 CYL • FWD • AUTOMATIC
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NINOGERMANA
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  • 2 POSTS
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
Dec 30, 2008 at 10:36 AM
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MMPRINCE4000
  • ✓Experienced 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.
Mar 2, 2021 at 1:29 AM
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