s5 TII fuel pressure question

FerociousP · 06-12-2011, 07:05 PM

S5 TII with a Sprint RE
stock s5 turbo
550cc/750cc injectors
FD fuel pump

Car originally had a Rtek 2.0 and ran great. Fuel pressure was 32psi at idle and 39-40 at 0psi or with engine off. Switched to the Sprint RE this week and when we started tuning I noticed that the fuel pressure was around 50 psi at idle. The fuel pressure doesn't change with vacuum and when revving the gauge sways a 1-2 psi either way. I am getting voltage for the pump from haltech fuse block so it is getting full voltage when running as it is no longer going through the fuel resistor box. No other changes to the fuel components were made and I didn't make any changes to the vac/boost reference for the FPR.

Is the FPR damaged?
Is the full voltage causing the FD pump to overwhelm the regulator?
What else could cause this?

*** Subquestion: Is the stock TII fuel pressure regulator rising rate?

06-12-2011, 07:05 PM	#1
FerociousP I-had-a-bad-experience... Join Date: Feb 2008 Location: M'boro Posts: 1,046 Rep Power: 19	s5 TII fuel pressure question S5 TII with a Sprint RE stock s5 turbo 550cc/750cc injectors FD fuel pump Car originally had a Rtek 2.0 and ran great. Fuel pressure was 32psi at idle and 39-40 at 0psi or with engine off. Switched to the Sprint RE this week and when we started tuning I noticed that the fuel pressure was around 50 psi at idle. The fuel pressure doesn't change with vacuum and when revving the gauge sways a 1-2 psi either way. I am getting voltage for the pump from haltech fuse block so it is getting full voltage when running as it is no longer going through the fuel resistor box. No other changes to the fuel components were made and I didn't make any changes to the vac/boost reference for the FPR. Is the FPR damaged? Is the full voltage causing the FD pump to overwhelm the regulator? What else could cause this? * Subquestion: Is the stock TII fuel pressure regulator rising rate? __________________ '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; 06-12-2011 at 07:07 PM.