240Z, 260Z, 280Z Performance / Technical Discussions related to performance motor enhancements, upgrades.

Time for a Fuel Pressure Regulator?

Old 06-12-2005, 12:44 AM
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Join Date: Dec 2000
Location: Cashmere, WA 98815
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Smile Time for a Fuel Pressure Regulator?

Just checking some things out, and was doing the fuel pressure test today.

I initially found that my fuel pump was only putting out 28 psi pressure. Then, I took the vacuum line off of the Fuel Pressure Regulator, and the fuel pressure shot up to 36 - 37 psi.

Then I hooked the vaccum line up again, ran the car at 3,600 - 4,200 rpms, and found that the fuel pressure dropped to 25 psi.

If I disconnect the vaccum line to the Fuel Pressure Regulator, and run the car at 3,600 - 4,200 rpm's, I have 36 - 38 psi fuel pressure.

So, I have concluded that my fuel pump and dampner are working good, and that I need a new Fuel Pressure Regulator. If you know of a inexpensive (cheap) place to buy one, please let me know.

Sunday, its valve adjustment day! Do you folks still use Hi-Tack for afixing the valve cover gasket to the valve cover?

Peace & Groovy! - Speed
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Old 06-15-2005, 10:24 AM
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One thing to note: the FSM has that ~36 psi spec as measured relative to the intake manifold pressure/vacuum. So, in theory that 25 psi at ~4k rpm would be correct if you also had 11 psi of vacuum. With the vac line detached, it sounds like your pressure regulator is okay. You may want to check your vacuum while measuring the fuel psi and see if the offset is correct or if the correction is being overdone. On the other hand, if you're looking for a good excuse to upgrade to a rising rate regulator, you could just go for it.
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