Fuel Pressure Regulator

[wytbishop]

HEre's a question...

The elbow fromt he ZE FRP was bent so I pulle dit off and looking at them side by side it seemed extremely similar to the K8 FPR. They both have 285cc injectors, however the part numbers are different. Has anyone used a K8 FPR on their ZE successfully for an extended period of time and does anyone know where i can get a ZE FPR?

Thanks.

[mx3autozam]

i am pretty sure they are the same. I was actually trying to figure this out today. I think the part numbers are different due to the bend in the line.

[RX8SE3P]

Well I was going to ask this and found this thread (late reply I know but better than started a new thread). I swapped my ZE FRP for my K8 one today. They both have KL on the part number, which would indicate 2.5L compatibility IMO. The ZE one does have a bend, but who needs that bend anyways? I put the K8 one and it seemed to run ok. Have not actually driven it. Will do and let you guys know. I reckon it will be fine.

[wytbishop]

I've been using it for most of a year now without issue. I do have a fuel consumption issue, but I don't think that's the cause.

[mx3sohc]

ZE Injectors are 220cc btw. Millenia S Injectors are 280cc.

[Daninski]

Umm ZE 220cc and K8 180cc. Good question tho. I'd be inclined to get a DE FPR. The K8 puts out like 28 psi right. If you had a pressure gauge you could check it out.

[Ice Racing]

KL fuel pressure should be between 39-45 at FPR has per Mazda shop manuel

[wytbishop]

Hmmm...I thought the ZE and K8 had the same injectors. I'm not using the PRC solenoid, I'm just taking vacuum straight from the manifold to the FPR. If it was restricting my fuel pressure I would be way lean and I'm pretty sure with my fuel consumption that is not the case.

[marcdh]

I remember reading OBDII k8 injectors were the same as KL, but I never saw any proof/conclusion.

I know my two OBDI k8 sets are 180cc or so and my ZE are the bigger 220cc or there abouts. 42psi is the number I always seem to read. Wideband, AFPR and megasquirt is the way to go

[Daninski]

If you read up on the FPR you'll find it does a few different things depending on the engine operating situation. Here's an over view

The FPR maintains a constant pressure differential between fuel system pressure and intake manifold pressure. When intake manifold pressure is low (high vacuum), fuel pressure is low. When intake manifold pressure is high (low vacuum), fuel pressure is high. This constant differential guarantees that, for a given pulse to the injectors, the volume of fuel dispensed at the injectors remains constant. In other words, the volume of fuel injected does not depend on engine load (for a given pulse).

Intake manifold vacuum is routed through a pressure regulator control solenoid valve. This solenoid valve is located to the right of the switching solenoid valve (see secondary air injection control system under emssions control system) and behaves similarly. When not energized, it conducts intake vacuum. When energized, it vents (to the atmosphere) the FPR. The pressure regulator control solenoid valve is energized only during a hot start condition. When intake air is hot (as indicated by intake air temperature sensor), the Engine Control Unit (ECU) energizes the solenoid valve and vents the FPR for 90 seconds. When the FPR is vented to the atmosphere (intake manifold pressure is maximum), the fuel pressure is raised to its upper limit (maximum fuel pressure).

At idle, the fuel pressure should be about 28.4 psi. When the FPR is vented to the atmosphere, the fuel pressure should be between 34.1 and 34.9 psi. With engine off, ignition key to the on position, and yellow connector jumped, the fuel pressure should be between 64.0 and 85.3 psi.