Just installed a digital 6AL on my 88 GTA. At 3000 rpm or WOT the tach went to zero. Here's the fix. Out of the MSD harness is a grey wire dedicated tach signal wire. There is a white tach wire in the factory harness that comes out off of the coil. There is a factory grey connector that attaches the white coil tach wire to white wire in the harness. Disconnect these two, and attach the grey MSD wire to the white wire that goes into the harness. Your tach will work fine. You will not need the 8910 tach adaptor. TA DA!

 

That's how the MSD installation instructions say to do it.

 

That's great but it wasn't in my instructions which is weird. Called MSD and worked it out with one of their techs.

 

It's probably been a dozen years ago but yeah, MSD sold me the tach adapter to try and fix the issue. I need to find the tach lead from the MSD 6AL.

 

Hi Guys,

I am getting ready to install a Digital 6A in my car (87 IROC).

Any updates on the issue?

I talked to MSD Tech support, they indicated that the 6201 should be connected per the harness that was developed for the dual connector coil.

Is this correct?

Best Regards,

Bruce

 

Might not help 100% but this is how I wired mine