zex ?

Discussion in 'Fox 5.0 Mustang Tech' started by tyler08, Mar 19, 2009.

  1. ok I have programed the nitrous management unit as the instructions say and for some reason the solenoid keeps turning over at around 3/4 throttle. I have started over and reprogrammed it 3 times now and keep getting the same results. Any ideas? do I have a bad tps? or is 3/4 the way to the floor full throttle to the computer?
  2. The unit works by saving the voltage sent out of the tps at full throttle. So something is happening that is making the unit store a voltage that is the same a 3/4 throttle.

    Basics first.
    Is the nitrous management unit grounded properly?
    Are you connected to the correct tps wire?
    Is the tps voltage set correctly to begin with?
    Are you programming the unit correctly?
    Is the throttle body butterfly operating correctly in relationship with the throttle pedal?
  3. man am I frusterated! ok so I reprogrammed the nmu and it will fire a full throttle now, unfortunately after wireing in the traction control switch setting thr rpm range from 3000-5800, I hit full throttle reach 3000rpm and........nothing! I'm sure I have everything programmed right and I know it is wired correctly. The rpm displayed on the switch matches the rpm on my tach so that is fine. MY feul pressure is good and its not the cut off switch preventing the solenoid from opening. Do I have a bad traction controll switch? One more question and maybe this is the problem. I'm a little confused with this progamming step on the tcs. What type of system is stock on a 87 gt 5.0?

    A. individual coil per cylinder systems where the TACH wire is connected to the coil

    B. coil packs that fire in pairs (waste spark systems) and the TACH wire is connected to the coil

    C. number of engine cylinders, from 2 to 12, where the TACH wire is connected to the tach
    from the engine electronic controller or distributor

    Thanks again!!!
  4. Well it don't come stock with coil over plugs, and it don't have a waste spark system, so I would have to say C.
  5. You have an 87 GT with traction control? Did you put that on there or was it stock cause I had no idea they had that in the 80s
  6. zex traction controll switch = rpm window switch
  7. Give ZEX a call... they should be able to offer some help. Good people over there and no one know more about their product than them.
  8. Zex has a Traction Control/Window Switch for their systems


    Tyler did you program the nitrous management before or after the traction/window switch install? The NMU has to be programmed 1st before the traction/window switch is installed because the traction/window switch works by interupting the tps signal to the NMU. Secondly, did you program the Skip-Shift? 0 turns it off iirc. Tach signal should be 02 or 12 iirc. Activation should be 030 for 3000 rpm. Deactivation should be 058 for 5800 rpm...
  9. Yes I programmed the NMU before installing the window switch, and also have the skip shift set at off or "o". What do you mean 02 or 12 iirc? Which one would it be on a stock ignition 87 gt?
  10. I said that wrong, I was still half asleep, I meant 2 thru 12 depending on the # of cylinders you have.. The tach settings should be 00 if it is coil on plug, which is not an 87 GT, 01 is for coil packs, which is not an 87 GT. You want to say 08 for 8 cyl.
  11. thanks Bubba that is what I set it at unfortunately it still wont fire. I cant see the problem. Its wired correctly, I programmed the nmu before wireing in the window switch, I am now certain the window switch is programmed correct. It was fireing at wot before I wired in the window switch. Its getting a proper tach signal because it matches the tach in the car. any other ideas. thanks a million!!! Jeff
  12. Here's what I would do to troublseshoot and I know this seems arbitrary and repetative:
    Step 1 - Unhook the NMU white wire from the TC. Also unhook the other white TC wire from the tps. Hook the NMU white wire to the tps. See if the kit is working correctly without TC. If it is proceed to step 2. If it isn't working correctly you found where the problem is.

    Step 2 - Keep both TC white wires unhooked for now. Completely remove the power and ground to the TC. Wait a good 30 seconds. Re-attach power and ground. Now reprogram the switch without the white wires attached. Now you can check the contintuity of the white wires (because the white wires are simply one wire that the switch normally keeps open (breaks them apart)and when the rpms that are programmed are met the switch closes the "break" for a complete path). To check this will take 2 people and a digital multimeter or ohm-meter. Unarm the NMU. Set the multimeter to continuity & put both leads of the multimeter together - the meter should chime or buzz. This tells you the meter is working correctly. Now put the red lead of the multimeter to a white wire from the TC. Then put the black lead from the multimeter to the other white wire. Start the car and go to the activate rpm when the switch is suppose to activate the multimeter will buzz or chime and stop when the you let off the throttle. If this test passes unhook the white wire from the NMU to the tps and hook it back to the TC. Hook the TC other white wire to the tps. System should work now. If the continuity test fails I would call ZEX as I would suspect a bad TC.
  13. ok so no continuity at all. The switch is always off no matter what you program it at or what rpm level you reach. I guess I'll be calling zex tommarow. I gotta tell ya I would not go zex again. The bottle pressure gauge they sent me was leeking fluid when it arrived and now the tcs is bad. On top of that I have sent them 3 friendly emails over the last week and not a response to one, so they are going to have one dissatisfied costomer on the phone tommarow. Thanks for all your help!!!
  14. That sux. Did you buy directly from Zex or through a retail store? I like their TC switch but I always go with the MSD window switch because they are only $80 and I have a box full of the rpm pills. You can usually find them used on Ebay for about $40.
  15. I bought the pressure gauge directly thru zex, and nitrous kit,purge,fuel pressure cut off switch, and tcs thru Brenspeed. I'm starting to wish I would have saved the money for a supercharger. Damn If I wasnt such and impulsive buyer! Now I gotta pay 25 bucks to reship it to.
  16. :notnice: I think Brenspeed sells junk/returned/demo/something Zex parts. 2 of my buddies bought Zex stuff from them. One got a bad gauge & a nozzle that had a broken jet mount and the other buddy got a NMU that was bad. I have always bought my Zex parts from Zex or Summit.
  17. ya well I'm not to happy at this point I've been waiting to see what she can do for 2 weeks and there is no tellin how long it'll take to get this stuff reshipped. I am gonna give someone a piece of my mind, 3 emails with no reponse after spending $1300 with someone dosnt go over well with me. thanks again for all your tech help. I am longtime mustang lover with little mechanical experience but I really am enjoying learning!!!