Ray@NitroDaves

that particular diagram is for a trans brake....for a 2 step you would replace the t-brake solenoid with the 2 step box...if your 2 step wires different...I will be happy to adjust the diagram if needed.

Since alot of guys here have the 685 I will add a diagram for that particular unit.

89385formula

I'm wiring challenged, could you add a FPSS and purge to the LS1 single stage, Nitrous Outlet TPS/window switch, Timing tuner diagram please. Also not to change the subject, on the LS1, what should the FPSS pressure be set at. It came preset at 35psi and it should be higher right since they run 55-58psi?

Ray@NitroDaves

The FPSS goes between the window switch and pin 85 of the first relay

The purge is a seperate circuit pulling its power from the ACC wire off the master arm switch

The FPSS should come with instructions on how to set it. You will activate the system then turn the adjusting screw clockwise until the system starts to pulse, then turn the screw counterclock wise 1/2-3/4 turn. This sets the operating window for pressure drop.

MEAN LT1

You have a single stage with a digital 6 wiring?

Ray@NitroDaves

use the 3rd one down....the MSD and Crane both use a 12v source to activate the timing retard

89385formula

I saw another diagram where the FPSS was between the 85 pin on the 2nd relay, rather then the grey wire from the timing tuner go to the 85 pin(it gets grounded), in this other diagram it went ground>FPSS>85 pin. Will this work? Also since I am only running one stage, can I use the yellow wire(1st stage) and completely disregard the orange wire and leave it disconnected?

Ray@NitroDaves

the FPSS will go inline on any of the low amp grounds (30 & 87 are the high amp pins, 86 & 85 are the low amp pins)

you just don't want to have it on the direct solenoid grounds

89385formula

Great, I think the way I wired it should work then. The only question I have is about the Yellow/Orange wires off the TPS/window switch. I used the yellow wire to connect to the 85 pin on the first relay, and the orange is disconnected. Will this work, or do I need to connect the orange wire as well? BTW you have been a HUGE help, thank you very much.

Chopstix

yellow = 1st stage control
orange = 2nd stage control

if you only have 1 stage you will not use the orange wire

89385formula

OK, I got the system all wired like the diagram. Go to spray, ...nothing. So I check my grounds and relocate to a better spot. However now I am trying to set the FPSS and it never starts to pulse? I am confused on this right now. Can anyone help simplify this for me?

Edit: I changed the wiring to bypass the FPSS, because I suspect it to be defective. I put the wiring exactly the way the diagram was for the LS1, single stage, Timing tuner, Your TPS/Window switch. I went WOT and it sprays. I then wired the FPSS inline on the grey wire between the timing tuner and the 85 pin on the 2nd relay. Now with the FPSS wired in, it will not spray. The system never starts to pulse when trying to adjust the FPSS operating window. Does this mean the FPSS is bad?

Ray@NitroDaves

bump

lt1rx798

dave, i have the lt1 plate kit. does the "86" post on the relay need to pass through the WOT swith before going to the acc. slot on the toggle? ...or does it go straight from "86" to toggle and "85" straight to the WOT?

i didn"t get instructions, and im wiring dumb........

blown94

great thread, definitely NEEDS to be sticky

texas94z

yeah this thread is needs to be a sticky. thanks for the info ray.

Injuneer

I hate to step on anyone's toes, but Kurt hasn't been here for almost three months, so I'll take care of making it a "sticky".