This is my first nitrous install and I'm running into a problem I can't explain. I'll preface the problem with the equipment I'm using.

Zex Single Fogger Wet Kit, Jetted at 75 shot.
MSD Window Switch, 3000 on, 6000 off. 4 cyl. mode

After hooking everything up, I go out hoping to get to rock the bottle. I heated the bottle, hooked up the nitrous line, went out to where I was going to make my pass. I opened the bottle, heard the nitrous fill the line, flipped the arming switch, started to roll slowly up to 25. Then I went WOT, at 3000 RPM I'm expecting a big kick. Nothing happens. Right after I slow down and pull over, I pop the hood to see if the fogger or nitrous line coming into the fogger is cold. It's not.

The window switch is wired so the yellow wire is connected to a relay. The White is connected to the tach sensor. It's grounded and powered off a fuse. The gray wire isn't used. It turns on when I turn on the car and reads the correct RPMs.

The Zex Nitrous Management Unit (NMU) has a red wire that connects to the relay. It's also grounded and has power. The white wire is connected to the TPS wire. The solenoids click when I push the throttle to the floor w/ the key in the "on" position.

The relay is grounded.

The thing I'm questioning myself on the most is the window switch. The yellow wire/gray wire situation was extremely confusing. Apparently you only use one or the other. After switching which of the two is connected to the relay, I still don't see any changes.

I'm lost at this point and can't think of any other way to troubleshoot my problem.

 

The noids shouldnt click when the car is just keyed on if your window switch is working.

 

Post your wiring diagram including the relays.

Three things are needed for the system to fire.
1. Nitrous armed
2. WOT
3. RPM in window

TA, is right you should not get the noids to click WOT key on.

 

What about your throttle position? If that is not set correctly it wont work. That is the beauty of a window switch. If all the necessary criteria arent met your nitrous doesnt fire. Kinda a safety feature. Youre missing something simple.

 

its either wiring, tps, or if that kit has a fuel safty it could be off a bit and not allowing it to spray

 

With my nitrous outlet wot/tps controller I can get my noids to click with key on/engine off wot. Just set rpm activation to zero. Works good for testing.

 

All the wires but the top one were connected to the relay when I bought the kit used. I know little to nothing about relays and how they work. There's a good probability that it's hooked up wrong and I don't know it.

 

Is your msd window switch the one with the pills you plug in out? I have the same one and is wired like this: Yellow(msd) to the relay, Red(msd) to a switched 12v, Black(msd) to a ground, and White(msd) to the rpm wire.

I think (its been a while) that the relay for the noids is grounded through the window switch.

 

I don't believe it has the pills. Its the digital version. The PN on the window switch is 8969.

 

Here is what a search came up with

https://ls1tech.com/forums/nitrous-o...-diagrams.html

 

Based on the diagram in the link, the relay isn't grounded to anything. I was under the assumption it needed one. Later tonight ill try rewiring the setup how its shown in that diagram.

 

did you ever figure it out? in my manual for the same window switch says that

1 cylinder: This program is used for individual coil per cyl system (such as gm ls-1 engines, or 99-up mustangs).

2 cyl: this is for ignitions with coil packs that fire 2 cyl at the same time. (waste spark systems).

2 cyl. odd: use on coil pack ignitions that are on odd-fire engines such as a viper v-10 or Harley-Davidson motorcycle

4-cyl: Typical 4-cyl engines with a distributor.

6-cyl: Typical 6-cyl engines with a distributor.

6-cyl. odd: Typical 6-cy odd-fire engines with distributor.

8-cyl: Typical 8 cyl engines with a distributor

hope this helps sense you have it set to 4cly makes me wonder if your window switch isnt reading the right firing from the coils and i believe it needs to be set to 1 cyl. that's what my manual shows

 

With the window switch hooked up in 4 cyl. mode, it reads the right RPMs. But I just reread my instruction manual and you would be correct about 1 cyl. mode. I have a 98 so there is a coil for each cylinder. I'll change it and see how it effects the car.

Hooked up the system as shown in the diagram I was linked to. Still nothing. There were 2 posts made at the end of that thread that said the diagram was correct except for a few things.

Guy #1 suggested hooking up the 30 of the relay to the battery without cutting the white TPS wire. In that case I'm confused as to what would take the place of 87.

Guy #2 said you set the TPS wire before connecting it to the relay. After the Zex NMU reads to WOT voltage, you cut the wire and attach either end to the 87 and 30 of the relay.

I did exactly like guy #2 said with no spray. Can someone back up guy #1 or do they both have it wrong?

 

I have a TNT kit and this is how my system is setup hope it helps i don't know if zex is kinda the same setup

relay

86: this one goes to micro switch

87: n20 solenoids

85: Yellow wire from window switch and the fuel safety switch hooks into this same wire

30: direct battery or alt. or positive battery source

*"87a middle hook up on the relay is not used"*

arming switch

1. ignition switched 12volts can find it in the fuse box 5th one down on the right

2. hooks to micro switch this should be in the middle of the switch

3. ground

 

looks like your system isnt hooked up right

 

Finally...
She sprays. Big props ovaboost. You pretty much had it right. I hooked up all my wires as directed. Since there are 2 red power wires coming out of the Zex NMU, I twisted them together and connected that to 87. 86 went to my switch. 85 went to the yellow wire on my MSD digital window switch. 30 went to the battery.

I still ran the window switch in 4 cyl. mode.

There is one last little thing that concerns me. When I got home and took a listen under the hood, I heard a slight hissing sound coming from the Zex NMU. Is this anything to be concerned about?

And is there any way to clear the line with the bottle closed or is this even necessary. I don't own a purge kit.

 

Your nitrous line is leaking. You need to take the fitting out of the NMU and re-seal it. I had to do mine and it was a PITA. Have fun.

 

AWESOME how does it compare to n/a and then using the spray? glad to see it work im not sure on your next question something could be leaking if your hearing that noise like c6 batmobile listed

 

It seems like all you'd do is unscrew it, slop some teflon paste on the threads and screw it back in.

But I am pretty new to this, so please explain why it's a PITA. I'm probably missing something.

 

So how did if feel Matt?

Does this mean we can go have some fun? Also, you should get a purge to clear the line before you spray and also to clear the line after you close the bottle and shut the car off.