I'm running a stock HEI distributer and just converted from an internal accel coil to external MSD blaster SS coil and have no tach.

I'm using MSD cap,rotor, modified dust cover, SS coil, and wires. No box. Car fires up and runs good, but no tach.

I've got both pink wires off the dizzy hooked up to pos on the coil and the brown to the neg on the coil. 2 black wires are not being used. Anyone know whats going on? Maybe a filter/resistor might be needed?

 

Take the 'tach' wire off the large cap and place it on the negative terminal of the external coil. If you used stock wiring for the external coil there should be a white pigtail already there to connect too.

RBob.

 

From the dizzy cap?

I have 5 wires on the cap two pink two black one brown. One pink one black and the brown are in a three prong harness the other pink and black are individual single prong harness. Don't see white? I assumed brown was my tach wire?

 

Yes, there is a terminal on the cap marked 'tach'.

I know little about the stock distributor wire colors. They varied too much over the years and models.

The white wire would be if you used the STOCK GM TYPE EXTERNAL COIL and CONNECTORS.

RBob.

 

I dont have the white wires, its a carb HEI.

I talked to msd, they are going to send me an inline resistor to try out but the guy on the phone didnt sound too sure about it.

Nobody has had this problem before?

 

As Rbob said, the wire that was originally connected to the "tach" terminal on the "in cap coil" HEI will need to be connected to the negative terminal on the external coil. If there was no resistor between the original HEI and the tach, you won't need one for the external coil setup. Some tachs require a resistor but that is tach specific, not distributor or coil specific. HTH!