Recently picked up a Zex Nitrous kit for my 8 but have ran into an issue that I can't seem to figure out, and I better ask before I start messing something up..


So my issue is with the programming on the kit. I tested the wires on the TB and found the wire that continually give off voltage according to the throttle position. I hooked up the white wire to this and went through the programming procedures given in the instructions. Went for a test drive... and.. nothing.


Went back and listened for the clicking that is supposed to happen at WOT. It didn't seem correct. Reprogrammed the module and I'm not sure if what is supposed to be happening is.. When I hit WOT there is a small click, almost as if the system is opening up, but a much louder click when the throttle is let go. I assumed this is correct after attempting the programming twice and having the same results.


Next test drive.


Opened bottle. Engaged system with throttle at maybe 10% while slow rolling. The RPMS and car jerked forward as if the system engaged as soon as I flipped the switch. Immediately switched the system to off.


Any ideas on what is going wrong here?? I get all of the correct programming lights and I'm assuming the correct clicks with the car off and WOT, but nothing seems to work correctly once driving.

 

I KNEW I read to use that bottom wire somewhere.. When looking I couldn't find where I saw that. I did use the bottom wire since I saw that somewhere. I'll try again with the engine fairly warm.

 

So just got back from another test run. Reprogrammed the system. Seemed to be activating when it should.

While driving, the first pull (2nd gear) w/nos engaged the car seemed to choke up around 8k rpms and bog down. Second pull was strong throughout the RPM range, hit red line and when I went to shift, it sounded like I fired a gun. Huge backfire, entire gauge lit up like a Christmas Tree and the motor turned off.

With that big of a backfire and the sluggish climb.. maybe weak plugs??? They only have about 8k on them but a shop flooded them pretty good once.

 

i was always told to spray between 4+-8k rpm and i did for many years without any problems. does your car run ok now? several members have blown up the uim due to n02 pooling. the best example was easy1e but his was an auto iirc

 

You know, I did go through yesterday and reprogram the system with the fuel lines attached.. Which lead to a sluggish semi-flooded start, so I went ahead and changed the plugs anyways figuring it wouldn't hurt to have brand news ones. Running after that it seems like night and day. Running much smoother. My only question to your response 200, is how do you only have it run between 4K-8k. If the system is engaged at WOT how does it turn off at 8k? Do you just back off WOT? This seems counterintuitive.

 

arm it just before you hit 4k, go wot and shift b4 you hit 9k

 

Makes sense, wasn't sure if there was a separate module that would control something like that.

Is there a recommended time, let's say, if I run nitrous that I should wait before turning the motor off? To basically to ensure there isn't any more in the lines. I have it about a mile or two but the following start up still seemed a bit rich.

 

i had a purge solinoid. not sure about the time thing. i never had an issue and ran my kit for years

 

Right on, I have a purge as well. Except when we went to install it, it leaked. We tightened it and the fitting on the hose split right down the middle after a couple of turns... I'll have a new line for it tomorrow and will try that.

 

Seems like it was, after going back and redoing the programming seems to be activating at the correct time now. I need to change something about my shutdown, I don't want to ruin my new plugs right away.

 

Just got my bottle refilled today and the purge working as it should. Thankfully now I can verify everything is working as it should. Kinda.. First pull with the nitrous activated the car pulled way harder than it did last time. Except again, when I let off the gas, around 7k, backfires and engine dies while doing 60mph. Not sure what would cause this.

 

Went back through everything today figure I'm just an idiot. Sure enough, the fuel line had a slight leak. Car started right up and idled like normal. Then after about 5 minutes and the motor was warm, I noticed the exhaust had "smoke" coming from it (I'm partially color blind so I cant really notice if it is a white or blue color) and it didn't sound like it was idling correctly. The smoke was coming out just as it would if it was very cold out and just blow away with the wind, but then it would slightly pop and look as if the exhaust was blowing an "o". Took it for a run around the block. At first drove fine. Pulled fine. Etc. Was heading back and when rolling up to stop signs the RPMs would go all over. From 500-1000-700- it was a mess. I would put the car in gear and try accelerating and all of a sudden it felt as if the clutch was slipping in every gear as soon and I was back on the gas. Got home, popped the hood while it barely idled and you could see the engine shaking as the RPMs went all over and the popping sound from the exhaust seemed to only get worse..

What have I done!!

 

I'm running the AEM intake and I did take it off while doing the install. Tomorrow I have the day off so I will go back over the entire intake system. My last run at high RPMs the car got very sluggish and sounded like it was drowning. As if it was flooding with gas. Hopefully didn't do too much damage..

 

As always, you're spot on Charles. Took the intake apart, realigned the screens, and cleaned the MAF. Car runs fine again. Only issue I'm having now is the car hesitates at high RPMs and even worse when the nitrous is engaged. I did replace my plugs and I have the BHR coils. No Cat. I pushed on the SSV lever and it seems to move with ease. Guess I'll be cleaning my ESS next.. Otherwise I'm lost again

 

I saw you were asking about a module to control nitrous activation/deactivation based on RPM. You can get a nitrous window switch that will do exactly that. Every proper nitrous setup should have one.


Also, do you have a wide band? If not I would suggest one it would tell you pretty quickly what is going on.


As you spray the nitrous bottle pressure decreases due to less volume of gas and a temperature decrease, this can cause the nitrous mixture to go rich. The other thing that could be happening is the opposite, you could have a weak fuel pump and be running out of fuel at high rpm due to the increased demand from the nitrous kit. Also, if I had to guess I would thin the kit would be on the rich side. Again a wideband would help here.


What is your bottle pressure before and after a hit?


OOPS looks like this a pretty old post, maybe it will still be helpful...

 

Greddy makes an RPM switch that I had always planned to use when I had N2O, but never got around to it. I believe Gregs did use it though for a shift light signal for his HKS display thingamajiggy. It is no easy to get a good tach signal though from what I recall. I think you tap into the ignition coil wiring.

 

Not to hijack an old tread, but I'm going to do exactly that. I have a ZEX kit laying around off of my old Civic Si and I am planning on using this on my 05 RX8. In addition to this i will be running and Innovate PSN-1 to help control it. The nozzle will be mounted in a throttle body spacer to insure proper atomization. Now to the fun bit, I have read countless threads on nitrous on the RX8, but do not understand why no one has successfully used more than a 55 shot. I have read of the pooling but don't understand why no one has attempted to fix this issue? My questions are, were these people spraying pre or post throttle body? Did these people have a wideband? If so, what were the AFRs? Is it possible that the fuel jet supplied for the larger shots is too large? Any help on this would be greatly appreciated!

 

I think the reason most have issues is they don't have the engine setup right or have proper nitrous control. To run something like a 100 shot you really need a step or 2 colder plugs, pull a few degrees of timing and have a proper window switch and wot switch. also you want to control nitrous pressures closely and make sure you have enough fuel pump.

 

The PSN-1 will only trigger it under the proper bottle pressure, rpm range and AFR. I think with that and i good tune i should be able to run a larger shot. Only one way to find out I guess.

 

a few here have ran 65 and 75 shots being that they come with the kit. wcs ran both for a while and easy blew up a few uim playing with bigger jets but he was autotragic. i ran 65 for a bit but switched back to 55 jets. i probably have some cobb logs and or dyno sheets with afr readings somewhere.