firemedic

OK, for a 2000 GT, 4.6.

Installed a new MSD Tach driver 8913 to run my used MSD window switch 8956.Tied driver into +coil wire, confirmed with ohm meter. Good ground also confirmed.

Hooked window switch up to driver, ground, and fuel pressure safety switch. On pill is 3100, off is 6200. All wiring is secured and checked.

So car flashed up, N2O heated purged and ready with a pushbutton switch wired in in place of the WOT for the "TEST". Rev up to app. 3600 RPM and hit the button......NOTHING.

Retrace and recheck. Look good, but no go. Remove wires from FPSS and it sprays no probs.

Call MSD/NX with only suggestion that FPSS is problem, but it works fine w/o Window switch.

So anyone have any ideas?

Is there a way to check if window switch is getting a signal, or is working?

Thanks. 911 need help!

5PointOHNO

maybe because you're wired into the pushbutton you are somehow bypassing the Switch?

Just a complete guess.... Thats a tough one man.

firemedic

Anyone have any idea's ?

1BADRIDE

Post up a wiring diagram of what you have done.

firemedic

I will try to post a copy, but it is the same diagram as NX shows on thier installation of a fuel pressure switch and window switch.

NXGHOST

I just wired mine up today. You used the wrong coil wire. You need to use the negative coil wire.

firemedic

Well I thank you for the reply, but have to question where you got that from? Following MSD Ignitions own installation guide, as well as speaking with thier techs they both state to tap into the coil posative wire.

"The MSD Tach Driver wires inline to the posative 12 volt supply wire. It senses current on the coil posative wire and converts it to a 12 volt signal output. To install the tach driver, the coil posative wire must be identified for your application".

So my next question of course is does yours work? Who suugested you wire it to the negative?

Thanks for your comments.

NXGHOST

Mine works. Its funny though, MSD told me to use the Negative.....

firemedic

If it works, who am I to argue right?

Is it the 8913 tach driver and 8956 window switch you are using?

MSD advised me to tap into the passenger side wire harness. Where did you tap into and which wire?

Thanks.

NXGHOST

I am using the digital version of the window switch. It requires no pills. I called MSD and got 5 different suggestions from 5 different people. Try the negative and set it on 2 cyl. This is what I had to do on mine. Keep in mind my car is a 96.