Where did you put your FPSS...

Where in the fuel line did you put your fuel pressure safty switch?

Fuel rail > fuel line > FPSS > Fuel solenoid

Originally posted by Loadre
Fuel rail > fuel line > FPSS > Fuel solenoid

So you have the adapter for the FPSS connected right to the solenoid?

As far as I can remember I do. I can go check tomorrow if you would like me to.

Originally posted by Loadre
As far as I can remember I do. I can go check tomorrow if you would like me to.

If you don't mind. You don't have a pic of it by any chance do you?

Someone on the board gave me the idea of putting the fpss after the fuel solenoid (fuel rail-noid-fpss-nozzle). Then only have it grounding your n2o solenoid. The idea is that not only will it make sure your fuel pressure is ok, it will also make sure that the fuel solenoid actually opened. This could save a very expensive accident if the fuel solenoid swelled shut or didn't open for some other reason.

I have the switch at my house, does anyone know if this will work? I think I will put it on tomorrow and find out unless someone tells me that this is a bad idea.

Dustin

Dustin,
If Iitw works can you re-post on this topic so I'll know. I'm not real sure how I want to set mine up yet.

Thanks,

I think there's a pic in my cardomain link in my sig. I don't know if you can see the adapter and FPSS, though. I'll go look tonight because I'm booked all day.

About the FPSS on the other side of the solenoid. It sounds like a GREAT idea, but it's not seeing fuel pressure until AFTER the solenoid is opened. Therefore, if your FPSS was seeing no pressure, the solenoids wouldn't even open would they?

I'm sitting in class trying to not let the teacher see so I'm rushing so my reasoning might not be right. Be back on later.

"Someone on the board gave me the idea of putting the fpss after the fuel solenoid (fuel rail-noid-fpss-nozzle). Then only have it grounding your n2o solenoid. The idea is that not only will it make sure your fuel pressure is ok, it will also make sure that the fuel solenoid actually opened. This could save a very expensive accident if the fuel solenoid swelled shut or didn't open for some other reason.

I have the switch at my house, does anyone know if this will work? I think I will put it on tomorrow and find out unless someone tells me that this is a bad idea."

Nope, good thought but there is no pressure AFTER the fuel solenoid until after it opens therfore it would never activate them. Maybe a FPSS that waited 1 sec before it read the pressure?

Originally posted by Loadre
I think there's a pic in my cardomain link in my sig. I don't know if you can see the adapter and FPSS, though. I'll go look tonight because I'm booked all day.

About the FPSS on the other side of the solenoid. It sounds like a GREAT idea, but it's not seeing fuel pressure until AFTER the solenoid is opened. Therefore, if your FPSS was seeing no pressure, the solenoids wouldn't even open would they?

I'm sitting in class trying to not let the teacher see so I'm rushing so my reasoning might not be right. Be back on later.

That's ture, I didn't even think of that. I couldn't see the FPSS in your pics if it's in there. Your solenoids are in plane view, but I couldn't see the switch.

"Nope, good thought but there is no pressure AFTER the fuel solenoid until after it opens therfore it would never activate them. Maybe a FPSS that waited 1 sec before it read the pressure?"

This is what I thought at first too, but it should work the way I explained it (I may not have explained it good enough).

The ground for the fuel solenoid is not run to the fpss (if it was you are right he fuel solenoid would not be able to open). Only the N2o solenoid is. When all of the switches are closed (system arm, window, WOT etc) The fuel solenoid and the N2o solenoid both see power. The Fuel solenoid is grounded straight to the chassis so it will open. The N2o solenoid is grounded to the chassis but through a fpss. It will only be grounded if the fuel solenoid opens and the fuel pressure is acceptable.

I'm not sure how well I explained it but maybe that clears up what I was thinking. I am pretty sure that the logic of the idea is good and should work in theroy. Unfortunately it just started raining and is supposed to for the rest of the week so I don't know when I can try it out. I am going to go set it up this way now anyway.

Dustin

ohhhhh I see, hey that is actually a really good idea in theory. The nitrous would be delayed until fuel pressure was up not sure if you would feel the delay or not but I really like your idea. I may be re-wiring my system! What does everyone else think?

BTW, the FPSS is in my pics in the cardomain link. Scroll down to the one of the fuel solenoid with the guy's hand in the way, click on it to enlarge. You're welcome.

Originally posted by Loadre
BTW, the FPSS is in my pics in the cardomain link. Scroll down to the one of the fuel solenoid with the guy's hand in the way, click on it to enlarge. You're welcome.

I saw it later. I was looking at the wrong picture.

I just hooked it up that way and if it is dry tomorrow I will go out and let you know how it works. I am thinking the delay will be almost too short to notice but we'll see.

Dustin

craig, You need a better pic or explanation? If so lemme know

dkeers, keep us posted on how it turns out.

Good and Bad:
I tried it out and it did not work as expected. The fuel and N2O noids both opened like they should have but then it started pulsing on and off. I don't think that the problem lies with the theroy of how it is set up though.

I think the problem is that the fpss cannot handle enough amps to provide a good ground for the N2O solenoid. All of the instructions on how to hook up a fpss say that it needs to ground a relay not a direct ground because it cannot handle it.

I think I have a solution to this. I am going to get a second relay and run power to my N2O and fuel solenoids from via separate relays. The same power source will turn both relays on but the N2O relay will only be grounded when the fpss is closed (ie the fuel noid has already opened and my fuel pressure is good)

I thought of another reason that this is a good idea. I have heard other people complain about pulsing from a fpss in a normal setup and I think there is 2 causes: 1) improper grounding (like I had and am fixing) and 2) when the fuel noid opens there is a pressure drop for a split second (think of holding your thumb over a garden hose then letting go - the water shoots out far then drops way back then flows at a constant rate). If pressure drops enough then the fuel noid snaps closed. As soon as it snaps closed the pressure will be back up and it will open again causing another pressure drop. This cycle is repeated and is more noticable on a large shot (150 or bigger). The way I have it set up the fuel noid is not controlled by the fpss so there will be no pulsing caused by the initial fuel pressure drop.

Sorry I have got long winded but I enjoy making anything better than it was designed so this is like a challenge for me now :)

BTW the delay was not noticable, the N2O hit almost imediately when I pressed the button, but then it pulsed off.

Let me know your thoughts, I would love for this too work. It could save me or someone else a motor. If I get it to work I will start another thread.

Dustin

Edit: When I bypassed the fpss it worked perfect just like before so I know the switch was the problem.

Originally posted by Loadre
craig, You need a better pic or explanation? If so lemme know

dkeers, keep us posted on how it turns out.

I found the one on your page. I just didn't look at the right picture the first time.

Dustin,

Try setting the FPSS all the way to its lowest setting, that would eliminate pressure problems it would open then regardless of pressure problems. Mine does that if the fuel pressure is low (car off with fuel in the rail). It doesn't sound like an amperage problem but keep up the work!

Hey I just thought of this also, the pressure is lower on the other side of the solenoid, I bet you anything if you drop the pressure threshold on that FPSS that it will work.

That sounds like a good idea, I will try that.

Does anyone know what fuel pressure an Ls1 runs at? I think it is 58 psi but I am not sure.

I don't really know what psi the switch is set at, I need to get a fitting for my air compressor so I can test it.

It might take me a few days to know if it works, it is raining and is supposed to snow saturday. :(

Dustin

Wouldn't setting the pressure all the way down to the lowest setting kind of defeat the purpose of having the FPSS in the first place?

Yes it would I meant just for testing to eliminate the possibility of it being an amperage problem.

how did this turn out?

I haven't changed anything yet. I've been busy and it is hard to get motivated to fix my N2O when it is working how I have it (bypassed fpss).

I saw someone on LS1tech was trying something similar and having trouble as well. I will post if I get it working.

Id love to hear how all this turns out. im instaling my nx kit right now and was wanting to put the fpss after the fuel noid (fuel rail,fuel noid,fpss, nozzle) i guess just for extra insurance incase the fuel noid stuck. But now i see the point of how will the fpss have pressure all the time. oh well i guess i'll just mount it before the fuel noid.
What noid do i see on a few of setups attached directly to the bottle?
Does anyone have a real closeup pic of the wot switch? i bought a NOS brand but dont see a real great way to run it without a lot of bending and turning. thanks

I'm pretty sure your talking about the one for the automatic bottle warmer.

bottle warmer? theres a solenoid for the warmer? i dont think thats what im talking about.:confused:

Originally posted by 94droptopz
bottle warmer? theres a solenoid for the warmer? i dont think thats what im talking about.:confused:

It's not a solenoid like you are thinking, but it looks like one, and it for the automatic bottle warmer. The one that uses a pressure sensor to turn the heater on and off.

oh ok. i just bought this kit used and it came with the bottle warmer but it was just hard wired to a switch so i guess he wasnt using the thing your speaking of.

where would be a good place to buy one or can i?