I installed the kit last week and did the wiring today. Went to go try it out and as soon as I go WOT it goes into failsafe. This is with the system armed or disarmed and empty bottle. I called zex up and the tech guy tells me that they have had that problem on some of the '05 kits and some of the F-150's that all use the drive by wire. We made sure I had tapped the yellow wire on the TPS and tells me that the way they are fixing it is to find the wire on the actual pedal sensor that swings from 0-5 volts or vice versa and tap that. Well I figure no problem--but none of the wires read 0-5, closest being 1-4 volts. Tapped that and as soon as I armed the system it just dumps fuel from the fuel jet without going WOT. So now im stumped and am desperately looking for help from somewhere. Anyone think of anything that I might have overlooked-even something stupid? Thanks, Jan

 

Sorry man... Mine is working fine, all I could suggest (and I'm sure you have already done this) is to double check everything. If still no luck I would send the Zex CPU back and have them replace it... It should work just as the instruction's say. You should'nt have to chase down wires, I would worry about a possible malfunction durring use if it didn't work properly from the get go. Wish I could be of more help, hopefully George, Dereck, or Cleveland will see this thread.

 

Thats weird. If u were able to program the TPS, and got the green armed and ready light from red, then it goes into failsafe once WOT...I would say its the control unit.

Im sure u tried, but I would reset it, and program the TPS once more..

Good luck

 

And here's another reason to not use Zex.

The only thing that I can think of is that the engine may be getting overly rich since you are not spraying nitrous but then again I dont know exactly how the managment unit reacts to a no nitrous situation.

Good luck though.

You need to tap that yellow wire near the throttle body.

-Dan

 

if it was doing this only while it was armed then I can see that maybe it could have something to do with there being no nitrous. But it is going into failsafe even with the system not armed....so there shouldnt be any signal coming from or going to the managment unit. IF I disconnect the tap on the yellow wire on the TPS then it is fine.
05STG1- I actually have not tried reprogramming the unit yet so I will try that tomorrow. Did everyone else follow the directions about holding the pedal down for 10 sec or did you have to go longer or shorter? I followed the directions the first time and the unit programmed successfully. I got fed up with trying to find the wire at the pedal tonight and I have to take my car in to the shop in the morning to get the gears/tru trac put in. I really need to figure this out before next wed bc I already have dyno time scheduled then. Im losing my hair over this and only at 23! Ill let you guys know what I figure out. thanks, Jan

 

Not trying to second guess you or anything but if the plugs were fouled wouldnt the car just stay in failsafe until the plugs were cleaned/replaced? As long as the TPS wire is disconnected the car runs fine with no failsafe. The problem almost has to be with the zex management unit or when I programmed it. SO.....TPS wire hooked up-goes into failsafe with system armed or disarmed. TPS wire unplugged- car runs fine and no failsafe. -Jan

BTW- The HT0's got here today and I will be putting them in before the dyno so I am going to check the plugs before the nitrous goes in. That is also the reason I havent hooked up a filled bottle yet, bc im waiting until Im on the dyno for that.

 

Reset it and go from there. Check your ground, be sure its a good one, and the connector is tight.
When I programmed mine, I held it for 10 seconds, or a little longer, and it was programmed.Turned off activation switch, then back on, and you should be good to go.
Its a simple unit, so it will either work, or wont. I would be calling ZEX for another unit stat if not. With the the TPS programmed, and no bottle hooked up I can sit there all day and click the soleniods on/off...not that I would want to.

After programming, did u test the solenoids as mentioned in the instructions? did they click? they should each time u go WOT, Key on engine off.

In the intructions it says if wires are crossed by mistake, the unit is shot!

cleveland,

Its really not that bad of a unit, or system to be honest. Ive had NOS and mostly Nitrous express products over my years, and this is fine for a strong street/strip car.Sure...not for an all strip ride, but its a good simple basic powerful kit.

 

Just an FYI but the Zex solenoids are known to be of bottom barrel quality and the management boxes are known for unstable power output, partially due to its pressure reading from the bottle. If you spend a lot of time with Zex on the dyno you should be able to see varied power output as time goes on with seperate dyno runs.

Back to the question at hand...

Since it seems that the trouble is only caused by the TPS hookup you may want to doublecheck the tap. Check to make sure that all electrical connections are clean and installed correctly. It is possible that the wiring within the box is somehow bad but I suspect its something that you've caused.

-Dan

 

I really dont see how I could have crossed any wires-theres only 3. I am using an existing ground in the engine bay, white wire to TPS and red to switch. Like you said it is a simple kit to install and I did car audio/alarm installation professionally for 3 years so im not a novice. Ill reset it when it gets back from the shop today. thanks for all the responses guys. -Jan

 

solder the wires! Not that it's gonna cure everything, but soldered wires are happy wires <--man that sounds corny.
Jan-I have a soldering gun if you need to use one. Besides, you can help me pull the motor on mine

 

LOL I did solder everything and then cut the wire going to the TPS and put a connector on it for testing purposes. But I will definately help you pull the motor- I have a brand new air powered engine lift too if you need it. Hopefully we can go for a ride in my car if I figure this nitrous crap out.

 

FYI..

We all know how u feel about the Zex kit.Bottom of the barrel, worst of the worst... When the subject comes up on the WWW, u make your point well known like the first post, and then the one afterwards.
Im simply a happy zex customer and passed that on as I trying to help a fellow ZEX user figure out his ride out. U may not like ZEX, but many,many other do. Like I said...its a good street kit, not race worthy.Maintaining pressure is the key, IMO
Dont worry cleveland your the nitrous guy...d

Hope u figure it out BLK3V, I recalled the wire crossing statement from the instructions, not implying anything bro. like u said, its a few wires only.

 

First question is: When was your car built?

My guess is it was built before November of 2004... You are most likely suffering from TSB 05-14-04.

I had the same problem with my Zex kit... Was very intermittent... Turned out to be a faulty Throttle Position Sensor... The TPS worked fine until I hooked the Zex up... and then would do the failsafe (wrench light) interimittently... And like you I hadn't even filled the bottle up!

My dealership was very cool about it... they replace my TPS under the TSB even though my Zex was fully installed!

 

Are you saying everyone with a 2005 Mustang is going to have to go to a dealer and get the TPS replaces based on the TSB?

This is interesting that this is the first I have heard you had to switch TPS on a brand new 2005 Mustang.. Have others had this same problem, or is this just a random situation where the Ford factory reverted to using older parts on a new car, and these parts happened to be knowned faulty parts which had been issued a TSB from the previous year.. Sound like BS to me..

 

There have been a couple of people with this problem... Apparently it seems like just attaching the Zex wire is enough to trigger the problem... You don't even have to have the Zex turned on! You remember all the roundy- round we played trying to track down my wrench light... LOL! Afte all was said and done... even replacing the Zex Control Unit, the only thing that fixed the problem was to replace the TPS. As it happened my car was built in the date range given by TSB 05-14-4, so the dealership did my for free, no questions asked... (Zex was installed, including wire in plain sight).

The TSB covers :

2003-2005 Thunderbird
2003-2005 LS
2005 Crown Victoria, Mustang
2005 Town Car, Navigator
2004-2005 Explorer, F-150
2005 E-Series, Expedition, F-Super Duty
2005 Grand Marquis
2004-2005 Mountaineer

I put a copy of the TSB here:
TSB 05-14-4

 

Edit:

Good to know SCRMING, important info for sure.

 

My kit works awesome and my MPH in my runs is dead on each run showing the kit is consistant if you have the bottle heater.ALSO ANYONE WITH THE SHAKER SYSTEM YOU CAN FIND CONSTANT 12V FROM THE PLUG FOR THE AMPS IN THE TRUNK.SO JUST PUT AN ON OFF SWITCH FROM IT TO THE BOTTLE HEATER AND A GROUND.NO NEED TO RUN AL THE WAY TO THE FRONT OF CAR.

 

i agree.... 20 passes... love it... as a matter of fact I just ordered a 2nd bottle... the maximizer kit... LOL