Stillen Fuel Pressure Spec?

tchertel

Quick question. Anybody out there with the Stillen SC kit know what their fuel pressure is at idle? I have been trying to through to Stillen for the last month; they don't return web inquiries, they don't answer their phone, they don't return emails. My fuel pressure gauge is reading 62 PSI at idle. I plan to test that against another gauge but would like to know if the Stillen kit should be idling at 62 PSI or if this way too high.

Any insight would be great appreciated. Stillen's customer service is garbage.

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2014 370z Touring Sport, Stillen supercharger, cat-back and oil cooler

ByThaBay

Base fuel pressure should be 51 psi. If you didn’t drill the Venturi in the pump housing the fuel pressure will be higher at idle. I usually leave it this way and adjust for it in the tune. From the factory there are already some significant compensations in place for this area of operation, they simply need to be reworked in the case of higher pressure at idle. If you’re one of my customers just contact me directly and I can review your logs and adjust the tune as need.

tchertel

That you so much for the reply and confirming that the fuel pressure should be along in line with the FSM. I am gonna have my guy pull the pump assembly and see if it didn't get drilled; if it did get drilled then maybe when the installer drilled it they didn't clean up well and maybe the regulator sucked in some debris. I believe the high fuel pressure is giving me my misfires at idle (putting too much fuel in the cylinders), especially on cold starts, as well as causing the idle to jump around. I want to get the idle to where it should be (hopefully it does not mean buying an entire pump assembly from Nissan just for the regulator) and then hope that my injectors did not get damaged from the excess pressure. I see my fuel pressure drop to zero within an hour and half (my truck will have at some pressure for days) so am also thinking my injectors may be leaking fuel into the cylinders causing those cold start misfires, hopefully not as I don't want to spend that kind of money on a car I want to dump. But then again, maybe the Nissan will drop off pressure faster than my truck, I don't know this car well enough and not near as much information out there for it like there is for my truck.

Oh yeah, and I verified the fuel across three separate gauges.

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2014 370z Touring Sport, Stillen supercharger, cat-back and oil cooler

ByThaBay

The cause of the P0300 is likely a lean condition and not a rich condition. It’s very common to get this code especially on the Stillen kits. Check your Afr at startup and verify it is within parameters. If it isn’t, ask your tuner to make adjustments. When you do your cold start, the system has to pressurize, it’s normal for the pressure be at zero at startup and build progressively once the car fires. In that moment while the system is pressurizing, if it doesn’t pressurize fast enough the car will have a misfire and the code will be detected. Try this: before you start your engine, with the ignition on, use a third-party tool to run the fuel pump for at least 10 seconds, then start the engine. See if that prevents the P0300 from happening.

tchertel

I can smell that it is rich upon the cold start. When I am driving the misfires go away. This is with the Stillen box tune and I even had it tuned by another guy and he could never dial-in the cold start. One time we had where it would not throw a P0300 on cold start but it threw two other codes; i don't remember the exacts of the codes but I remember something about exhaust too cold and timing too high...something like that. The Stillen tune and setup never gave me a problem over the first 7 months or so of operation but something happened on a road trip, the car hiccupped like it was running out of fuel (but wasn't and never threw a CEL) and then the very next morning I had a P0300 show up on the cold start. By the way, the cold start AFR shows right about 14.7 to 1 once it runs up to fast idle and pretty much remains there as it comes down. I see misfires on all cylinders, about 2 to 3 times more misfires on bank 1 then bank 2 and most of the misfires fall in cylinder 3 with #1 close behind it. Plugs are good (GTR plugs gapped down a little bit), coils are good (the misfires did not follow when swapping them around), TBs are clean and the voltages of the TB Pos Sensor are almost complete exact across all four sensors.

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2014 370z Touring Sport, Stillen supercharger, cat-back and oil cooler