MSD - tach wiring, Success !!!!!! Options

[watsonrx13]

OK, I have finally wired the tach using ALL MSD supplied parts.

First, the MSD tach adapter has to be an 8920. (Can someone (DD) please contact PP and have them change their MSD ignition tech article?

Anyway here's the wiring:

1. Red and Black wires from the 'front side' of the MSD box to the battery. Red to + (positive), Black to - (negative).
2. Orange and Black wires from the 'front side' of the MSD box to the coil. Orange to + (positive), Black to - (negative).
3. Violet and Green wires from the 'back side' of the MSD box to the adapter then to the Mallory distributor. (There's only one way the wires will connect using their supplied quick connect.)
4. Red and White wires from the 'front side' of the MSD box. The white wire is not used (please cover with electrical tape). The red wire will connect to a 'pig tail'.
5. There are 4 wires that come out of the tach adapter. Red to 'pig tail'. White to the tach output on the 'back side' of the MSD box. Violet to the purple/black wire (from the car's wiring harness) that used to be connected to the negative (-) side of the coil, originally. Black to ground.
6. Finally, the black wire (from the car's wiring harness) that used to connect to the positive (+) side of the coil originally, connected to the 'pig tail'.

Once everything was wired correctly, the car started and ran great. Also the tach worked.... (IMG:style_emoticons/default/biggrin.gif)

BTW, my car is a '74 2.0l. The tach is the silver dot, with the (2) turn indicators.

Before purchasing the tach adapter, I would recommend wiring the purple/black to the tach output on the MSD box first. If the tach doesn't work, then purchase the 8920 tach adapter. I purchased the tach adapter locally for $50.

I hope that this will help others that have tried to use the original tach. There have been several members that have recommended either purchasing a new tach or sending the tach out to 'convert' it.

Here's a shot of everything hooked up....

I'll post a wiring diagram tomorrow...

-- Rob