Nitrous Guys, Input on Cutout Issue

[3VPOWA]

I just recently finished installing my Zex nitrous kit on my car. I went and had my bottle filled by a reputable guy in my hometown and tried out the 75-shot last night, however, I ran into a small problem.

The nitrous kit consists of: Zex Blackout kit (purchased new from a member here), Zex window switch (new) and Zex purge (hooked up but I couldn't find a crush fitting last night to reroute the purge outlet). I also purchased FRPP spark plugs that are one degree colder but they aren't gapped to .035 because I'm not sure how you exactly gap them (I know there's a certain tool but I don't know how you use it). They are gapped to whatever they are out of the box.

So last night I get everything finished up and go out and test the 75-shot. I purged the line once before playing around because I don't have the tube routed out of the engine bay to where I can purge it without issue. I set the window switch to spray in all gears, set 00 for tach signal, 3200 rpm activation, 5900 deactivation. Rev limiter is set at 6500 rpm, but I shift at 6100 rpm (Raptor shift light).

From a dead stop I armed the system. Sprayed fine in first and second, but when I shifted to third it felt like it wasn't spraying (rpm drops to ~4200 when shifting to the next gear) and then it would kick on around 5200 rpm and back off. When I would shift to third the car would backfire (however, it did this before spraying nitrous too). I'm running my 87-octane tune with 93 in the tank per BBR's advice.

I didn't have my bottle heater hooked up last night because the fitting messed up where the pressure sensor is. I also don't have my Cobalt nitrous pressure gauge hooked up yet because I bought it used and thought that it came with the harness but it only came with about 1 foot of wire on each end (just ordered a new harness).

The performance mods on the car are BBR Stage 1 Cams (NSR), SLP o/r x-pipe, SLP LMII resonators mid-mounted, and SLP LM axle-backs, JLT II CAI, and Steeda Billet CMDP's.

I know it's hard to troubleshoot stuff like this over the Internet. I was wondering if anyone had some type of idea what could be the possible cause. I'm taking it later this summer to HPP to get it tuned. I plan to pull the plugs tonight to see how they look.

From what I've read browsing the Internet, it seems to be either spark plug blowout or fuel pressure drop.

 

[Corpo]

One thing I learnt from datalogging is you have less issues with consistency if you spray right until you shift. The fpdm gets a little confused if you give it alot of time to react.

And it can't hurt to pull your plugs and check them. You should be able to get some kinda gap gauge checker and at least check em.

 

[3VPOWA]

One thing I learnt from datalogging is you have less issues with consistency if you spray right until you shift. The fpdm gets a little confused if you give it alot of time to react.

And it can't hurt to pull your plugs and check them. You should be able to get some kinda gap gauge checker and at least check em.

You know, that would make sense. Because shifting from 2nd to 3rd takes a little longer than 1st - 2nd so I could see that.

I'm a beginner when it comes to nitrous which is why I went with the Zex kit. I know you can screw anything up though.

Before I spray it again I'm definitely gapping the plugs. I did a search on here and found out how. Just need to buy the gapper and a feeler gauge.

Also, should I set the window switch to deactivate right at 6100 rpm since that's around where I shift? I was afraid of the system still spraying and pooling up, but I think that shouldn't happen with the WOT switch, correct?

 

[Corpo]

I was worried about that too, but when the solenoid shuts the fuel pressure spikes to like 60psi and the fpdm dc drops to 0 for that pressure to drop, that happens just as you shift and the solenoid opens back up. Suddenly your fuel pressure drops to 20psi and you spike lean, I hit 17 on my wideband. Not a good situation. It's alot less crazy on the system to spray right through the gear shifts. So yes, upper limit set when you shift.

If your worried about pooling after you cross the trap go half throttle for a few seconds to let your car suck up and of the juice that may or may not be in there.

 

[jeffie on juice]

Get ready for issues,on top of issues with NOS

I always left the FRPP plugs alone never gapped them and never had a issue with spark blowout til i started using my 150shot plate system.
How cold was it outside when u were spraying? bottle presure
if the bottle was super low you might of been dumping to much fuel into the system and just flooding it. Without a bottle warmer i wouldn't even spray. Get yourself a on a dnyo and see whats going on

 

[07 procharger]

your stock plug gap is fine for a 75 shot , dont worry about gapping them

 

[07 procharger]

you nedd a bottle pressure gauge and a heater. constant bottle pressure is a must for consistant sucsess while spraying. \it only takes a second to wreck shit with this stuff

 

[07 procharger]

corpo....aka street racer, sell me your rims.

 

[s8v4o]

Get ready for issues,on top of issues with NOS

I always left the FRPP plugs alone never gapped them and never had a issue with spark blowout til i started using my 150shot plate system.
How cold was it outside when u were spraying? bottle presure
if the bottle was super low you might of been dumping to much fuel into the system and just flooding it. Without a bottle warmer i wouldn't even spray. Get yourself a on a dnyo and see whats going on

If the nitrous pressure is too low the system won't even open the solenoids.

 

[3VPOWA]

I was worried about that too, but when the solenoid shuts the fuel pressure spikes to like 60psi and the fpdm dc drops to 0 for that pressure to drop, that happens just as you shift and the solenoid opens back up. Suddenly your fuel pressure drops to 20psi and you spike lean, I hit 17 on my wideband. Not a good situation. It's alot less crazy on the system to spray right through the gear shifts. So yes, upper limit set when you shift.

If your worried about pooling after you cross the trap go half throttle for a few seconds to let your car suck up and of the juice that may or may not be in there.

I'll give that a try once I get my fittings in from Jegs to hook up my gauge and pressure sensor for my DynoTune bottle heater.

Get ready for issues,on top of issues with NOS

I always left the FRPP plugs alone never gapped them and never had a issue with spark blowout til i started using my 150shot plate system.
How cold was it outside when u were spraying? bottle presure
if the bottle was super low you might of been dumping to much fuel into the system and just flooding it. Without a bottle warmer i wouldn't even spray. Get yourself a on a dnyo and see whats going on

I thought you loved nitrous and have sprayed it for years?

Car ran like normal when it wasn't spraying and then you could feel it kick back in at 5200 rpm when in 3rd. There wasn't detonation, pinging, lugging, etc. from the motor. It was probably 80 something degrees out.

your stock plug gap is fine for a 75 shot , dont worry about gapping them

That's what I was told as well.

you nedd a bottle pressure gauge and a heater. constant bottle pressure is a must for consistant sucsess while spraying. \it only takes a second to wreck shit with this stuff

I have both. The bottle heater is hooked up I just need the fitting to mount the pressure sensor to (has been ordered). The gauge I bought on here only came with a few inches of wire on both the sender end and the gauge end when it's supposed to be an 8-foot harness. I had to ordered a new sender harness from Jegs and will be putting it in next weekend.

 

[Mach1Marauder]

Zex is just a PITB!

Only good thing Zex came up with is the 4150 perimeter plate.

 

[Corpo]

If the nitrous pressure is too low the system won't even open the solenoids.

Likely without the heater the bottle pressure is dropping too low, causing the system to shut. Forgot about that with the zex kit. It does monitor pressure doesn't it.

corpo....aka street racer, sell me your rims.

No, lol.

 

[3VPOWA]

Zex is just a PITB!

Only good thing Zex came up with is the 4150 perimeter plate.

I kind of wish I went with a NX kit but for the price on the Zex kit I couldn't pass it up.

Likely without the heater the bottle pressure is dropping too low, causing the system to shut. Forgot about that with the zex kit. It does monitor pressure doesn't it.No, lol.

That's something that came to mind as well.

 

[pitbull4.6]

sounds like its lean.
I had a similar issue, I ended up going 2 points bigger on the fuel and it fixed the problem.

 

[3VPOWA]

sounds like its lean.
I had a similar issue, I ended up going 2 points bigger on the fuel and it fixed the problem.

That would stop it from spraying?



Also, I'm not using it again until I at least get the heater and gauge hooked up.

 

[3VPOWA]

Still having this problem.

Went to Dallas Raceway tonight to see how the car would run. Every time I sprayed you could feel the nitrous pulsating. We took the nozzle off the CAI, took of the fuel and nitrous lines, and cranked the car up to see what came out when "WOT". The nitrous line sprayed fine, however, barely to no fuel came out.

I know everything is wired in right. Zex NMU, Zex TCS, etc. I'm starting to wonder if it's a fuel issue?

EDIT: I also upped the fuel jet size but that didn't seem to cure the problem.

 

[TheKurgan]

Is your window switch reading the correct rpm at idle ? Not close, I mean exactly ? Which wire you tapping into to get your signal ?

 

[J2L06GT]

Do you have a "fuel pressure switch" on rail,
could be dropping when system fires.

 

[Corpo]

How is your fuel filter? Possibly something plugging up the solenoid. Or maybe a solenoid failure. Soo many things can be the cause

 

[07 procharger]

Im gonna say its the fuel noid. Can you get at them on the zex kit? Need to pull it apart and see if there is a chunk of shit in there.