I installed a zex nitrous kit on my car about two months ago. Car was running fine it was however super rich on nitrous, reading 10.0-10.5 which didn't bother me better rich then lean. But recently the car has been running really lean and on top of that there's times where the nitrous won't activate, it will be on but won activate on wot . I went ahead and installed a walbro 255 and still the same problem, idk what else it could be, I was thinking maybe it's the zex fuel solenoid but i don't know. Anyone have any info or had similar problems? If I didn't explain myself good enough or need more clarification just let me know. Thanks in advance.

 

Are you running the Zex box or individual solendois? If you are running the box and it is not activating, then you need to reprogram the box for WOT.

Also which wire did you tap into to get the Wide Open Throttle (WOT) signal?

 

I have the zex box, and the box was working perfect at first and out of nowhere it started doing this, ive already reset it, and i tapped into the yellow tps wire.

 

if the car is running fine without nitrous and lean with nitrous, sounds like your fuel solenoid is messed up. Tapping into the yellow wire off the throttle body can cause issues too. A better wire to tap is off the gas pedal inside the car. Do a search for Zex and resistor. There is some resistor needed to make the box work with the throttle body yellow wire.

 

Yea I know and I have the resistor wire hooked up, and thinking of taking this box off and just buy new solenoids and see then.

 

Why not get the right size for the jets? Running rich can be just as bad as running lean.

As said above, if you're lean when nitrous is on and at WOT, then your fuel solenoid isn't working properly. And if your nitrous just doesn't work at all randomly, then your box needs to be replaced/fixed. I say go with individual solenoids if you're going to replace.

 

... The same thing was happening to me ... Check the tps white wire .... I put mine like all straight i remove the resistor and problem solved ... I havent have any check engine light or anything ... And now mine activate everytine without any problem... Also get a tune man i know a place that do uprev tune and is cheap ... When car is running lean or rich u have more chance of causing engine damage ... Also i think i have seen u in florida do u have a silver 350z with infinity g35 rims and black paint in the front bumper?????????

 

And clyons0203 The resistor is not to mske the box work with the yellow wire ... The resistor is just to prevent a check engine light cus nissan system is so sensitive that a check engine light can come on just for that ... I remove my tps wire all i have now is the white wire all straight ... And havent have any issues ... No check engine light also ... sometimes when u connect so many wires together the wire cant get the bolts it should cus of all the connection you should have now .. White wire from zex box attached to tps and tps to yellow wire ... All i have is the white wire from the box straight to the yellow wire and welded .... When i did it .. It solve my problem ... I know how it feels when u gonna race someone and the nos dont get activated ... and u check box and light is green how it should be when it happen is the signal wire ... The box can be on but if the wire that let the box know when to get activated on wot is bad ur in the same boat ... That was my problem 1 month ago to ... Hope it help man ...