In desperate need of immediate help!! I can't get the idle fuel pressure to change. I set my static fuel pressure to 40psi (as high as I can get it) and then put the vaccuum line on and it dropped to 25psi at idle. I started with the vaccuum screw on the S-FMU all the way in and turned it until it was half an inch out of the S-FMU itself, and the idle fuel pressure never changed.

HELP!!

Which spring do you have in it? I had the same problem a few weeks ago, put the shorter darker spring in and fixed my problems.

That happened to me too. I was getting like 30 psi of fuel pressure on idle, and it wouldn't rise no matter what. Theoretically, my car should've died, but it didn't. There's a small little metallic pipe thing, on each end it has a hole (1 hole is larger than the other), best I can describe it, that goes inline with the vac.line, MAKE SURE YOU ATTACH THAT. I'm 98% sure this will cure your problem. I reserve the 2%, incase I'm wrong :P

I do have the restrictor in the line. I left the S-FMU just the way I received it from Vortech because I'm trying to get about a 3.5:1 rise rate, so I don't have the darker spring inside.

Can I take it apart to install the darker spring without removing it from the car??

"Can I take it apart to install the darker spring without removing it from the car??"

yes you can. just remove the allen screws like i think there are 6 of them and the spring will be inside. i would remove/loosen the static screw alot so it wont put as much pressure when you remove/install the lid back on.
good luck





Michael 99gs
HRC Stage 2
Stage 3 process begins gathering parts for rebuild

http://www.dreamwater.net/purplebeast

Thanks for the info and quick replys guys!! I swapped the spring and it fixed everything!!!

The idle adjustment screw won't do much of anything. That's normal. Set your static pressure and put the vac line on and you basically get what you get. There's not much you can do about it. When you put the short dark spring in there you'll notice that the pressure changes a lot more with each turn of the screw. You should be able to get up to about 60 psi static with it. What size injectors do you have anyway?

I have my static FP at 42psi, and my idle FP at 30psi. I'm running 415cc injectors. I took the car out last night with a datalogger and tuned my SAFC to get close to zero on my fuel trims. Everything seems to be good now.

I even did a few pulls at 15psi. Felt really good, except for some reason my car isn't holding boost. It hits 15psi and falls all the way back to 10. I'll have to troubleshoot that today.

good to hear you got it worked out. mostly once you set static for idle it drops down 8-12psi once you hook up the vacuum lines back up together. do you have a ignition to retard for 15psi with bigger injectors?.. just be careful dude.. also check how much timing your getting at wot etc at 15psi...
good luck



Michael 99gs
HRC Stage 2
Stage 3 process begins gathering parts for rebuild

http://www.dreamwater.net/purplebeast

I don't have an ignition for timing retard yet, that's next on my shopping list. So I won't be running 15psi daily. I just did it twice to check fuel pressures and trims. The second time I did log timing and it looked okay. I'm not gonna push it though.

I have another problem though, knocking/ticking noise in my engine, but I'm about to start a thread about that because I need some suggestions....