so we are tuning a stock ecu s5 t2 with an fcon. it has all the emissions removed.



we put it on the wideband and you can see it go lean over 5000rpms, ok so we keep turning up the fcon and that just makes it bog harder below 4k but it really didnt change over 5k rpms.



we were thinking fuel pump until paul suggested the fuel pressure solenoid.



check the codes, we get #25, pressure regulator control (fuel pressure solenoid), i plug solenoid into connector



BAM!



10.9:1 afr all the way up to redline, problem fixed



this could easily pop your motor.....

good info

oh yes, THIS DOES NOT TURN ON THE CHECK ENGINE LIGHT

you mean that thing that only effects fuel pressue for 30 secs durring a hot start?......



how is it gona blow my motor https://www.nopistons.com/forums/pub...1047683561.gif

I thought you said you removed emissions? Is this not in the rats nest?

yes if thats not plugged in the ecu doesnt turn on the secondary injectors

um i just plugged the solenoid in electrically, there are no vacuum lines hooked up to it

dude thats scary. We will find out when the LM-1 gets here on my buddies s5 t2...

yeah double check it, i would love to be wrong. granted it did fix this car

well mines been gone for a while....

damn i need to go check codes

well if it's removed you'll probably get codes. but that doesn't mean it's causing any harm... just mean it won't do what it was surposed to do.

i've still got every single solenoid. I still have the cold start assist

=)

Can I get pics of the fuel pressure solenoid? Maybe that would explain my unstable fuel pressure bouncing between 30-35psi when I hit the gas. Would that explain it? A bad connection, or something? Or is just my damn fuel filter, which is the only part which isn't either brand new, or has been replaced..

you may have been running 14:1 afr over 4500rpm too.... maybe not can you check to see if you get a code 25? it wont turn on the light by itself

well I have too many codes to count https://www.nopistons.com/forums/pub...1047683664.gif https://www.nopistons.com/forums/pub...1047683664.gif



but it ran the exact same the day after everything was removed as the day before... including the EGT's.



no wideband.

hmm wierd

oh damn great info! I know my car has been running lean up high, no wb yet, but pullin o2 sensor and plugs it looks that way. I'm gunna go look for that solenoid tomorrow and plug it back in and see what happens. I'm only hitting 10psi max in the high gears and have a walbro, so i didnt think i should be runnin lean. Maybe this will be a simple fix.

Another thing you can do... just plug it the FPR to the manifold. I believe the only thing the solenoid does is disconnect the FPR from the manifold during starting to give slightly higher fuel pressure when starting the engine. Most people who run aftermarket (so I hear) run with the FPR connected directly to the manifold (per ReTed's instructions to me regarding setting up my Haltech when I get it - so don't take my interpretation as gospel - its how I understand it to work). So maybe it will hurt a stock setup when starting to wire it up this way, but I dunno. Once I get the haltech in it will certainly go straight to the manifold though.



But I also have a fuel pressure gauge and a wideband so I'm gonna keep a sharp eye on everything. https://www.nopistons.com/forums/pub...#>/biggrin.png

the japanese market cars dont have this solenoid, so it doesnt seem to do anything super important, except maybe not blow up the motor

That's odd you say that ... my TII JDM engine has it. But then, my TII JDM engine also had the fuel rails set up A-spec style (FPR on the secondary rail) ... but still does not have the full ACV solenoid setup like an A-spec does, so go figure...

The jspec fuel rails have the fpr on the primary rail? so fuel enters the secondary and the return comes off the primary? Damn i gotta check my setup if this is true.

Japanese engines change from Zenki to Kouki. the Zenki early model cars had the FPR on the primary rail and the Later models have it on the Secondary rail.

If running a aftermarket FPR we mix the two rails eliminating the stock regulator.



They all have the FPR solenoid.