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-   Honda CRX / EF Civic (1988 - 1991) (https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/)
-   -   Fuel Pressure check (https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/fuel-pressure-check-2729110/)

luggss 02-16-2010 05:12 PM

Fuel Pressure check
 
I have a 91 civic with a swaped in Zc engine, do they have fuel pressure test ports? if not where it the best place to tap in to? What should the pressure be? and can i hurt any thing by installing a higher volume pump or should i just install a stock Si pump?

Thanks in advance.

sanimalp 02-16-2010 11:05 PM

Re: Fuel Pressure check
 
first, yes there is a test port. Its on the input side of the fuel filter mounted to the firewall. There are 2 banjo bolts that go into the fuel filter. The one on the left is a normal looking bolt head, and the one on the right looks like the side view of a doughnut with another smaller bolt in it. That smaller bolt is a service port that you can plug fuel pressure guages into. you should be seeing between 40 and 50 psi with the fuel pressure regulator vacuum line unplugged.

I would strongly recommend installing a stock pump unless you plan to run an engine management system of some kind. look at it this way. The stock fuel system has a fixed volume of piping, so installing a fuel pump that provides greater flow(volume/time) means higher pressure at the fuel rail, and thus more fuel injected. The ecu is just using lookup tables, most of the time, to decide how long to keep the injectors open, so higher pressure at the same injector duration will provide more fuel. Essentially, you will run rich nearly all the time unless you re-tune the car for the higher fuel pressure caused by the higher volume pump.

as a final note, you shouldnt read this as "you should only get a honda fuel pump". you should read it "if you don't want to tune your car, you should find a fuel pump that matches the stock rating, which is 79 lph"


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