I have a nitrous works 175 shot hooked up to an MSD window switch and a full throttle switch. N20 on @ 3000 rpm and off @ 5900 rpm. I power shift at 5700 rpm, engine revs over 6000 during shifts. (I'm retarding the timing 7 degrees and running TR6IX's)

Problem: On the first run the nitrous shut off in 3rd gear for about 1 to 1-1/2 seconds. Back on again to the finish line. I'm pretty sure it was only the nitrous because it fell flat on it's face for that short amount of time.

I took out the 5900 rpm pill for the second pass thinking the window switch shut it down because the engine went well above 5900 rpm.

On the second pass, it shut down again in 3rd gear for nearly 2 seconds, fell flat on it's face (black smoke out the tail pipes as told to me by spectators) {This is why I'm pretty sure it's just the nitrous solenoid}, then kicked in again and blew out the side of my gutted cat with a loud backfire with flames coming out from under the car.

1) Does this sound like a defective solenoid?
2) Or, has this happened to anyone else and if so, what was the problem and the fix?

 

Just a thought....Any chance that your Fuel pressure safety switch (if your running one) is shutting the nitrous solenoid off when (or if) your fuel pressure is slightly dropping below it's preset level, and then kicking it back on again when the fuel pressure returns to normal again.......sometimes if they're set right on the edge, it will do stuff like that.......good luck with it......Joe

 

Black smoke and backfires are normally caused by running very rich. Since it's a wet system I would guess you N2O solenoid is the only one cutting out, this could be the result of many different things. Check over the wiring first to make sre a safety devise is not wired to that solenoid alone. Also look for a bad or loose ground on that solenoid, if thats all good disconect the lines from your engine and test run is for a few seconds and see if the solenoid gets real hot or shuts down. If it does then you need to get a new one.

Other things to check, N20 filter, bottle presure, or anything else in your setup that would cause it to run rich.

 

The noids are wired together from the relay switch, so both get power from the same source. (That's correct according to the wiring diagram).

They are both attached to a mounting plate that is attached (grounded) to the intake manifold.

The pressure (Hobb's) switch is attached to the relay and provides a ground to activate the relay switch. So both noids would shut off if the fuel pressure were the culprit.

The black smoke, according to onlookers, came out only for a short time in the middle of the run (which explains that the nitrous solenoid is the culprit) or faulty wiring to the noid circuit.

I did notice the other day that there was a slight miss of the nitrous system when I was testing it on the street. It happened twice, for a 1/2 of a second or so. I didn't notice it when it was set up for a 100 shot.

How does a noid begin to fail? By failing, I'm assuming that it no longer opens. Does it start shutting a little at a time before it fails completely?