tording99Z28

iTrader: (3)

So I have a wet kit nitrous system on my 99Z28. I am running Compucar solenoids with a FPSS, WOT switch, Zex window switch, and HSW Interface. When I arm the kit and hit it you can feel the nitrous cutting in and out. I have the FPSS set at 45 PSI so if the pressure drops below this it will cut off. Is this too high still do you think? the FPSS is the only thing I can think of that could be causing this. Any thoughts?

Robert56

iTrader: (2)

I would double check all wiring. A gremlin somewhere, no doubt. It does sound like the somewhat common on/off from a FPSS that isn't set correctly. An easy way totake that out of the picture is to just put both wires on one terminal, and doesn't which one, then you have bypassed it and if the issue goes away, bingo, if not time for more diagnostics.
robert

tording99Z28

iTrader: (3)

I thought about bypassing the FPSS like you suggested but I am worried that if I really am running out of fuel pressure I will go lean and detonate.

JUNK

U gotta set the fpss lower, if u install a pressure gauge u will see that it spikes upon activation and takes a second to recover. Find the point at which it will not "cycle". It will be lower than u feel safe with, just make sure the fuel system is up to the task. Fuel systems w/ the return line/regulator in the back instead of the fuel rails will have the greater temporary pressure drop.

dudeman

iTrader: (43)

mine did that. it was a wiring problem. stupid butt connectors.

Nitro Dave's Nitrous Outlet

iTrader: (25)

First put a pressure gauge on the car. The Fuel pressure safety switch may be doing its job. Why bypass it? That just defeats the purpose in even having the switch on the car. If you put a pressure gauge on the car and the pressure is droping a few psi when the system hits causing the FPSS to kill the system re adjust it. If the car is having a significant amount of pressure drop you need to work on the fuel system.

If the fpss is not killing the system check the windoswitch connections and settings. Also check the wot switch and make sure the throttle arm is making good contact through the entire rotation.
Dave

1 QUIK LS1

iTrader: (4)

Mine was doing that same thing....drove me cazy lol, I wont go through everything i checked but i had put my hand on the activation switch on the T.B. and moved it ever so slightly and that was 'my' problem. On OFF,On Off lol.

Eagle02

iTrader: (20)

Surprised no one else suggested this yet, but is your bottle installed correctly? If the pickup tube is not at the lowest point in the bottle you'll get surging just like this too. Let's just say I know from experience. :blush:

Thought I'd throw that out there for ya. Otherwise, can you tell if the system is automagically going on/off on its own? If it is then it seems like the fuel system is where you need to look.

-Eagle

Nick@HSW

iTrader: (4)

If you're having issues with the fuel pressure, address that first by getting a gauge on there. Chances are its the fpss and I see people by-passing them all the time. This is why I'm generally not a big fan of them. For a better way of doing things, take a look at the microEDGE for the a/f shut down capability. If you have an inherent flaw with the cars rear mounted regulator etc and the spike catches up you can program the a/f shut down switch around it with our easy to use menu system. HOWEVER, I am in no way shape or form telling you to ignore the problems you're seeing now. You need to address them first.

Nick

WE TODD DID

iTrader: (2)

Is it shutting off, or is it rich? Also, do you have the solenoids wired through a relay?

Robert56

iTrader: (2)

Your only doing it for a diagnostic test. You want to pin point your issue and this is the best way to see if the FPSS has anything to do with it. Your running it right now, so taking this out of the picture is not going to change your a/f ratio and put a small hit in that won't have achance of doing any harm. Its just a test, then put it back once it is adjusted correctly. yes having a gauge is best, but not everyone has one in their tool box. You can set up the FPSS with a air comp at the work bench also, and it is a very common problem having these come out of wack. like all set-ups, the a/f ratio should be checked when your done, then this will tell you wether you need to go further and find a fuel system issue itself.
Once I insatlled a Microedge my FPSS was dumped, not needed.
Robert