s5 TII fuel pressure question

FerociousP · 06-17-2011, 09:37 PM

ok. Everything is NOT OK. I bolted everything back down and started the car. Fuel pressure stayed at 40psi until revved and went to 50psi. Seems to still coorelate with the battery voltage as I was getting 12.5V at startup and 13.5V volts AFTER i revved. Engine vacuum is at 17inHg and is definitely what the fpr is seeing. After the car warmed up I revved a little more aggresively. It even got a little boost, about 3-4 psi, and the pressure actually started falling!! It fell to just under 40psi as the rpms rose and entered boost. It seems to be doing the OPPOSITE of what it should be! I'm so confused. Ideas anyone?

** With the gauge on the return, I saw NO pressure at all, so I have no restriction in my return line.

With the new (used) secondary rail:

Car off 12V: 40-42psi
13.5V and 17in/hg vac at idle: 50psi
pressure falls with revs

06-17-2011, 09:37 PM	#6
FerociousP I-had-a-bad-experience... Join Date: Feb 2008 Location: M'boro Posts: 1,046 Rep Power: 19	ok. Everything is NOT OK. I bolted everything back down and started the car. Fuel pressure stayed at 40psi until revved and went to 50psi. Seems to still coorelate with the battery voltage as I was getting 12.5V at startup and 13.5V volts AFTER i revved. Engine vacuum is at 17inHg and is definitely what the fpr is seeing. After the car warmed up I revved a little more aggresively. It even got a little boost, about 3-4 psi, and the pressure actually started falling!! It fell to just under 40psi as the rpms rose and entered boost. It seems to be doing the OPPOSITE of what it should be! I'm so confused. Ideas anyone? With the gauge on the return, I saw NO pressure at all, so I have no restriction in my return line. With the new (used) secondary rail: Car off 12V: 40-42psi 13.5V and 17in/hg vac at idle: 50psi pressure falls with revs __________________ '15 Juke Nismo '06 MX-5 GT SOLD '04 S Silver RX-8 GT Track Day Use SOLD '90 Black TII vert w/ Sprint RE stock port/turbo DD dyno (242.6whp@5500rpm @12psi 8psi@redline) and (250ftlbtq@4800rpm @13psi) SOLD '89 GTUs 6p TII SOLD, '87 sport SOLD, '79 SA stock SOLD '91 B2600i 4x4 w/ Rx-8 LSD SOLD** Last edited by FerociousP; 06-17-2011 at 09:39 PM.