94NDTA

I tried my system, didn't work. Opened botle, turned on heater, purged, waited till the pressure raised, then turned the arming switch on....nothing. Everything seemed to work when we tested the system. We tested the system with the bottle closed, we reved it to 3000 RPM, and tapped the WOT switch, but got nothing, we thought because at half throttle at 3,000 rpm, there isn't enough fuel pressure and didn't ground the system. So we grounded the FPSS, and it worked. I think the problem lies somewhere in the window switch in my Mallory 685, but I thought I had it hooked up right. PLEASE look at this if you have any idea on whats wrong!
http://www.piranha-fury.com/photopos...schematich.jpg

WS6_Keith

My question would be where is the FPSS mounted in the fuel system? How far is the fuel solenoid from the rail port? What is the pressure set for? Did you test the system with the vacuum line off the regulator - which simulates WOT?

94NDTA

FPSS is mounted right before the solenoid, roughly right infront of the fuel port, maybe 8 inches away. The pressure is set at 35 psi. We tested it by gounding the FPSS, with the bottle closed, by pressing the WOT switch, and the solenoids clicked on. I don't know the way you are talking about to test it.

12SCNDZ

Everything else is wired correctly. My system is way more complex than yours because I'm using a digital progressive "maximizer", NX TPS switch, and MSD digital spark retard. My system uses 3 relays. My MSD trigger wire needs to be taken FROM ground to retard the timing. It taps into my solenoid positive wire.

I know I've worked closely with both MSD and NX to get mine wired right. Josh Phillips, at NX, is a great person to deal with. His e-mail address is josh@nitrousexpress.com

Frank

12SCNDZ

...Another suggestion is to jet the system for a 50 HP shot, and just wire the FPSS to ground, and see if the system works.

Frank

94NDTA

Should I wait till it is above 3000 RPM and let off before the shift as well? It is an Auto.

EDIT: Do I need to ground the FPSS and then hook the window switch wire before the FPSS? I always thought that the mallory served as a ground, but it doesn't seem to be working.

WS6_Keith

The problem you are having is due to the drop in pressure in the line between the rail port and the 'noid. When the 'noid opens, you get this drop in pressure, since the pump can't instantly fill that line between the 'noid and the jet.

Move the pressure switch back to the rail port, away from the 'noid.

94NDTA

I have it in the same spot where everyone and their mom has their FPSS on an NX system, right before the fuel sol.

WS6_Keith

The further the run from the rail port to the solenoid, the more this will influence it. My first setup had the fuel solenoid mounted behind the driver side headlight, with about 6' of line to the port. With it hooked up as you describe, it did exactly what you said. Once I moved it to the fitting at the rail port, the problem went away.

94NDTA

I don't think it is possible to get it any closer, or to have it go right off the fuel port. There are a lot of people running the same way as I am.

DrewHMS97SS

you did ask the question. unless you are running a 3' line it would be worth the try. also that is the craziest way to wire a FPSS ive ever seen. you want your nitrous to cut when pressure drops, not stop the retard.

sssalah

This is wired correctly, the violet wire is the window switch wire for the mallory 685, that is a typo on the diagram.
By the way I have my fpss mounted about 5' away from the fuel port (below the battery tray) and its working properly.
Check the Mallory to see if it gives earth to the voilet wire and choose low rpm settings for testing purpose.

94NDTA

It is actually a 2' line from the fuel port. It would stop the retard because it is suppose to break the ground to the relay, shutting off power to the noids as well. I'll give that a try sssalah.

DrewHMS97SS

if the line is that short i dont see a problem as to where you have the fpss. did you test the fpss for what pressure it will break the circut at?

94NDTA

It is set at 35 psi. How do you test it?