Having problem with N20 wiring.

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Super73
Posts: 107
Joined: Sun Oct 07, 2007 2:56 am

Having problem with N20 wiring.

#1 Post by Super73 » Wed Dec 23, 2009 7:02 pm

Attached you will find a wiring diagram that I created for my set up. A few things about it.

2 stage NX kit.
2 arming switches, one for each stage.
Throttle switch
Fuel pressure safety switch
Single Window switch: Can not take a large ground (like noids) so I am using it to ground the coil of the relays.

I was testing it last night in the shop with it wired as shown minus the window switch. I didn't want to be reving the motor while my buddy tried listening to noids ect to see if things were working. The wire going from the Fuel Pressure Safety was left loose so I could simply ground it to the chassis as if it were through the window. Things weren't working right.

We found that some how there was a grounding issue and when arming the system (with the WS wire grounded) it was firing the noids with out the throttle switch being depressed. Double checked the throttle switch with a meter to make sure it was normally open and working right. All is fine with it. So we decided to disconnect the input of the throttle switch (ground from the relay coil 86). Flip the switches, still firing the noids.

We disconnected the 86 wire from relay and tested our circuit for a short to ground, IE through the throttle switch and through the fuel pressure safety switch. No short or ground.

The next thing we check were the arming switches since they go to ground for the LED or light in them. +12 in and Acc both are free of ground when off but both go to ground when on.

We disconnected the ground for the arming switches, and what do you know. Works perfect. Each stage will engage and release with the throttle switch, and both will as well if they are both armed.. They both work right with the window switch wire being manually grounded and ungrounded as if I was the switch..

I swapped (85) and (86) for the fun of it to see if any difference. No I didn't notice if it was doing this or not with them wired as the diagram but:

If the ground is hooked up to the arming switches, if 1 stage is armed alone with the WS wire grounded, the noids will not fire till WOT, but, they will not release if I lift or unground the WS. I have to turn the switch off. But if both stages are armed, they both will come on and off with the throttle assuming the WS wire is grounded.

Again, disconnecting the ground on the switches, works perfect.

So I'm hoping someone can tell me what would be causing this. I'm thinking I might just buy a couple nonlighted switches since I know it works right that way..

Would putting a diode on both (86)'s possibly fix the issue?
Attachments
n20_wiring.JPG

Mick
Posts: 24
Joined: Thu Jun 15, 2006 12:33 pm

Re: Having problem with N20 wiring.

#2 Post by Mick » Wed Dec 23, 2009 7:28 pm

mick here

certain relays will not work for your setup. i belive bosch relays are what you will have to use is bosch relays. john heard or adam wright here on drag stuff
can explain why.

Super73
Posts: 107
Joined: Sun Oct 07, 2007 2:56 am

Re: Having problem with N20 wiring.

#3 Post by Super73 » Wed Dec 23, 2009 11:34 pm

Not sure what comes in the NX kit.. But I know some of them run a diode in the relay to keep current from flowing the wrong way on the coil. It would appear these don't have a diode on the coil.

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John_Heard
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Re: Having problem with N20 wiring.

#4 Post by John_Heard » Thu Dec 24, 2009 6:51 am

That's certainly a weird one, as the light on your arming switches and/or it's ground should not be affecting the circuit as shown. From the looks of the diagram, I can't see how it would be doing what you're saying either. Without a ground on the relay coil (86) it should not operate. Are these both Bosch or Tyco Style relays? The terminal numbers you're using sound like it but ?

If you remove both 85 and 86 wires from the relays, and touch a hot wire to either one, does the relay activate? If so it must be internally grounding the relay coil wire somehow, like through the mounting bracket?

Super73
Posts: 107
Joined: Sun Oct 07, 2007 2:56 am

Re: Having problem with N20 wiring.

#5 Post by Super73 » Thu Dec 24, 2009 12:47 pm

John,

I don't think they are self grounding relays as they are in a plastic shell with the mounting tab/hole on the back top. They are the Relays that came with the NX kit. They do not have the normally closed 87a tab either. I will try putting power to both of the coil sides individually and see what it does.

I have a couple extra Bosh Relays that I can put in the harness and see if that changes things.

Very whacky though that the switches are effecting it this way. I have 2 extra lighted switches that I tried, same effect..

Super73
Posts: 107
Joined: Sun Oct 07, 2007 2:56 am

Re: Having problem with N20 wiring.

#6 Post by Super73 » Thu Dec 24, 2009 5:04 pm

I could change it to this.. This is almost how NX says to do it.. Only changes is there is normally a push button between the Stage 2 switch and relay. Also the relays normally go to ground vs the window switch..
Attachments
N20 wiring 2.JPG

Dykes&Strippers
Posts: 12
Joined: Fri Feb 06, 2009 10:01 am
Location: Lebanon, OH

Re: Having problem with N20 wiring.

#7 Post by Dykes&Strippers » Mon Feb 01, 2010 1:49 pm

Super73 wrote:Attached you will find a wiring diagram that I created for my set up. A few things about it.

2 stage NX kit.
2 arming switches, one for each stage.
Throttle switch
Fuel pressure safety switch
Single Window switch: Can not take a large ground (like noids) so I am using it to ground the coil of the relays.

I was testing it last night in the shop with it wired as shown minus the window switch. I didn't want to be reving the motor while my buddy tried listening to noids ect to see if things were working. The wire going from the Fuel Pressure Safety was left loose so I could simply ground it to the chassis as if it were through the window. Things weren't working right.

We found that some how there was a grounding issue and when arming the system (with the WS wire grounded) it was firing the noids with out the throttle switch being depressed. Double checked the throttle switch with a meter to make sure it was normally open and working right. All is fine with it. So we decided to disconnect the input of the throttle switch (ground from the relay coil 86). Flip the switches, still firing the noids.

We disconnected the 86 wire from relay and tested our circuit for a short to ground, IE through the throttle switch and through the fuel pressure safety switch. No short or ground.

The next thing we check were the arming switches since they go to ground for the LED or light in them. +12 in and Acc both are free of ground when off but both go to ground when on.

We disconnected the ground for the arming switches, and what do you know. Works perfect. Each stage will engage and release with the throttle switch, and both will as well if they are both armed.. They both work right with the window switch wire being manually grounded and ungrounded as if I was the switch..

I swapped (85) and (86) for the fun of it to see if any difference. No I didn't notice if it was doing this or not with them wired as the diagram but:

If the ground is hooked up to the arming switches, if 1 stage is armed alone with the WS wire grounded, the noids will not fire till WOT, but, they will not release if I lift or unground the WS. I have to turn the switch off. But if both stages are armed, they both will come on and off with the throttle assuming the WS wire is grounded.

Again, disconnecting the ground on the switches, works perfect.

So I'm hoping someone can tell me what would be causing this. I'm thinking I might just buy a couple nonlighted switches since I know it works right that way..

Would putting a diode on both (86)'s possibly fix the issue?

Not sure if you got this fixed yet, but it sounds like you have the arming switches wired incorrectly. It does matter which terminal you bring power in on, because of the light.... I wasn't paying attention the other day wiring up one of my new switch panels and put the power feeds on the wrong terminal and I had relays switching with the switches in the off position. Those relays only take a tenth of an amp to switch, so a back feed through the switch light is very possible. I bet if you switch the power feed it all goes away!
Dykes & Strippers Custom Wiring
Lebanon, OH
513-617-5717

Harry Clack Dragster, 388" sbc, 4.80 @ 141

1978 Monza, 406 sbc, 5.59 @ 125

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