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Those of you with NOS please test and answer :)

Joined
10 March 2000
Messages
77
Location
NY USA
okay fuel pressure safty switch should be open until it reaches 50psi to provide ground to one of the solenoids. The other solenoid just ground near the mounting spot.

here is the funny thing with my installation....when the first solenoid that's grounded near the mounting spot the circuit for the fuel pressure safty switch is closed...which mean Nitrous will flow regardless of the fuel pressure switch...however if you remove the ground away from the first solenoid the fuel pressure safty switch is open....

it almost seems the ground on the 1st solenoid is connected to the second....

I took my voltmeter...and found that there is continuity between the two wires ( one from each solenoid) that is suppose to go to 1 the ground 2 the fuel pressure safty switch....i would think they should be independent...

so could you guys with the nos kit please take your voltmeter and connect the two points on the fuel pressure safty switch and let me know if there is continuity....or tell me if i did something wrong.
 
You are measuring exactly what you should be but you aren't measuring what you think you are :-)

Look at your circuit diagram (you made one right?). With the engine off, the pressure switch is indeed open but you can't just measure the voltage drop across the terminals with the circuit intact.

What you are actually measuring in this case is the continuity through the following: one terminal of the switch to the body ground. Then through the body to the solenoid 1 ground then through the solenoid (it's a coil). From there, through solenoid 2 (it's a coil) and back to the other terminal of the pressure switch. That's why you're measuring continuity. You're not measuring the continuity across the switch. You just measured the continuity of the solenoid and pressure switch circuit. This was one of my tests I performed when installing my NOS to ensure my grounds were good. :-)

Hope that's not too confusing.

Vic
 
Originally posted by vicster:
You are measuring exactly what you should be but you aren't measuring what you think you are :-)

Look at your circuit diagram (you made one right?). With the engine off, the pressure switch is indeed open but you can't just measure the voltage drop across the terminals with the circuit intact.

What you are actually measuring in this case is the continuity through the following: one terminal of the switch to the body ground. Then through the body to the solenoid 1 ground then through the solenoid (it's a coil). From there, through solenoid 2 (it's a coil) and back to the other terminal of the pressure switch. That's why you're measuring continuity. You're not measuring the continuity across the switch. You just measured the continuity of the solenoid and pressure switch circuit. This was one of my tests I performed when installing my NOS to ensure my grounds were good. :-)

Hope that's not too confusing.

Vic

that's what i thought at first...it was measuring something else...however the Nitrous activates when the fuel pressure is at zero...this is my second pressure switch..so i don't think that's it. Yet when i remove the ground on the first then the second solenoid does not activate...thou it should since it requires both to activate in order for the NOS to shoot out.....
 
Originally posted by Tetsuo:
that's what i thought at first...it was measuring something else...however the Nitrous activates when the fuel pressure is at zero...this is my second pressure switch..so i don't think that's it. Yet when i remove the ground on the first then the second solenoid does not activate...thou it should since it requires both to activate in order for the NOS to shoot out.....


I assume you've adjusted the Fuel Pressure switch so it closes the circuit at the second stage of the fuel pump (about 3000 rpm).... :-)

The solenoids are plumbed in series but wired in parallel then in series with the fuel switch. If you remove the ground to the first solenoid and prevent it from opening then NOS cannot flow to the second one and no NOS will pass.

Basically this should happen if you wire your solenoids in parallel and then in series with the fuel press. switch (FPS):

- short FPS ---> both solenoids can activate
- short FPS, disconnect sol #1 grnd --> only sol #2 can activate.
- short FPS --> both solenoids can activate.

Private me (vicster or vicster2) if you want my wiring diagram to verify with yours.

Good luck,
Vic
 
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