Putting a fuel pressure safety switch in...

this will work right?


I edited the picture but it won't show up... solenoid on the left is fuel.. solenoid on the right is n2o

hold on a sec... i forgot to throw in the relay.. gimme a second to redo it..

 

The FPSS needs to be in line on the relay ground in between the window switch and the relay

 

ok edumicate me... my friend and i are going back and forth on this..

using your diagram the fpss will have to be before the solenoid correct (between the fuel rail and the solenoid), which means the fpss will only go out if the fuel pump is going bad, fuel leak

using the diagram on the top, i can put the fpss AFTER the solenoid, which will make it a safety feature as putting it before, as well as keep a sticking/bad fuel solenoid from killing my engine.

granted if the fpss triggers in MY schematic, it will just cut off the n2o solenoid, and i'll be spraying just fuel into my engine, it will still give me added protection against a bad fuel solenoid.

correct?

 

no, you need to do it like he said.....


You need it to shut down the whole system via the relay

 

Too much fuel=bad things

 

Just fyi, my nitrous set up is wired as per Ray's schematic(can't go wrong with tried and true).... I was just curious if anyone saw any big downsides to the one I posted, because I am more concerned with a bad fuel solenoid then I am with a bad fuel pump...

 

Id be more worried about the f/p then the solenoid. If the pump is stock and your spraying the stock pump isnt made to handle much more than a stock pressure but the solenoid is made to handle the pressure.

 

I have a walbro 255 lph

 

if the FPSS' tap into the fuel line is downstream of the solenoid the system will never activate as the line has zero pressure until the solenoid opens....if the FPSS is set to deactivate the system at 35psi, it would have to see more than 35psi to close the circuit.

 

ok not trying to come off as a jerk... but are you even looking at the schematic I posted?

The window switch turns on the fuel solenoid, and then when fuel starts going downstream of the solenoid it turns on the nitrous solenoid....

It theoritically should turn on, but will have a millasecond of differences between the opening of the fuel solenoid and the opening of the n2o solenoid

 

Why in the hell would you want the fuel to come on before the nitrous and not at the same time???

 

Can you not read? Look at the schematic and read post #3, I'm not repeating myself..

 

Read post #5 for my response. I to am not repeating myself. Good Luck

 

allright then, breaking it down barney style.. if the solenoid got stuck closed/partially open, the fuel pressure safety switch would still see there is ample pressure (since there is pressure in the fuel rail) and let the system still run. So I would be spraying a 150 shot of just nitrous into my engine, after the MAF, which means kaboom.

if such a situation happened with my suggested schematic, it would cut off the nitrous and just shoot the fuel in it. Granted that's not the ideal situation, it sure beats the alternative.

 

Pin 30 is constant 12v
Pin 85 is ground
Pin 86 is the coil trigger
When the coil is triggered by applying 12v, it will complete a circuit from Pin 30 to Pin 87 and send power out of Pin 87

According to your diagram...there are multiple problems
When 12v is appiled via the wire connected to pin 30...the solenoids are going to see instantaneous power but there is no ground...you have the ground wire from the nitrous solenoid attached to the FPSS. The ground for the Fuel solenoid is attached to the other side of the FPSS and the 12v trigger for the relay. In your diagram the solenoids have no ground and will not open.

The FPSS is tapped in to the nozzle side of the fuel solenoid and will see 0psi until the fuel solenoid opens. Even if you were able to supply ground from Pin 86 the FPSS will break that ground until the fuel solenoid opens.

I am assuming you have the output from the window switch attached to pin 87 on the relay. If for some reason the relay does open....the relay is going to send power out pin 87 and melt your window switch.