Hi all, I am going to replace the original fuel pump for the 4AGZE engine.
How should I find the correct LPH for my engine. The engine is stock except with a bigger pulley.
How to ensure the correct amount of fuel is injected into the engine after changing a bigger pump?
Do I also need to install a adjustable fuel regulator and AFR gauge to work togwlether with the new pump?

I see from many topics pointed the direction for bigger fuel pump but not one telling much on the adjustment.

Thanks a lot.

I ran 15psi on a 4AGE with GZE injectors and the stock AE86 GTS fuel pump.
Never had a fuel supply problem. Used the GZE factory FPR but did have an
aftermarket ECU so I could tune the fuel.

The factory ECU can probably stretch to accommodate a couple of extra psi
over stock. But in saying that, boosted engines don't like running lean. Having
a WBO2 gauge and an adjustable FPR is never a bad thing as you can keep an
eye on your AFR and tweak the pressure if need be.

The FPR controls the rail pressure by regulating the flow. If you put in a bigger
pump the rail pressure does not change. The FPR just bypasses more fuel back
to the tank. Going to a "500hp pump" does not make any more power. But it can
max out the FPR leading to a excessive rail pressure and a rich condition.

I doubt that you would need any more than a 125l/hr pump if you want to buy
a non-stock pump. Circulating too much gas thru the FPR just heats the fuel
up, and you might have to get an adjustable FPR to handle the extra flow.

Cheers... jondee86

I use a 7mge pump out of a 92 Cressida