I bought a EFI fuel pressure safety switch from cold fusion, which came with no instructions. Looking at it I got an idea of how to hook it up, but i'm not too sure I want to be playing guessing games. So, how do I hook this up exactly? Also, is this FPSS adjustable? How do I check and adjust it after I install it?

 

The switch is wired in series with the the WOT switch, this way your nitrous system won't fire unless the engine is in WOT and you have the required fuel pressure. Yes the FPSS is adjustable. I set my switch so that it just triggers at idle fuel pressure; at WOT your fuel pressure should be higher as long as your fuel pump can keep up with the fuel demand. With the nitrous line(s) pulled off, arm your system and close the WOT switch to fire the nitrous. Now you can test the FPSS and see when it's active and when it's off. If you have a window switch, set it to a low rpm value for this test.

 

thanks for the info on how to test it, I prolly wouldn't have thought of that. Actually, I looked a little into this after I made this post. Well first off I called up the direct cold fusion number and they told me the same as you about wiring the fpss right before the wot and some other stuff that was kinda confusing, so i went ahead and checked out the NX website and they had a awesome wiring diagram that includes wiring the window switch and the fpss, go here: http://www.nitrousexpress.com/Instructions/fpss.pdf

Only thing that is different from what you told me and the cold fusion sales guy is their complete diagram (pg. 4) runs the yellow wire (from the msd window switch) to the fpss negative and a wire (shown white for nx, not the same on mine) from the fpss positve to the relay. Then there is a separate wire that runs the positive from the battery to the WOT switch and then to a different connector on the relay. Will this also work just as well? With the FPSS, is the best way to hook it up to the fuel to just hook up one end to the schradder valve on the fuel line and the other end to line that goes to the fuel solenoid?

 

The point of mounting well not matter, at the schrader valve or the noid.. NOid is probably cleaner and easy to get to..
try this one, it show the numbers on the relay.
Hope this helps..
Ricky

 

that wiring diagram is real nice, thanks man.

 

go to www.barrygrant.com and look for nitrous works --lt1 instructions. They have multiple schematics that differ from the one posted above. That is a cool diagram though