Making 90 Tach work with 91 ECU

[Grip]

Can someone point me in the right direction to get my tach to work correctly after swapping a 91 ECU into my 1990 GSX. It jumps around and doesnt work properly at all. I have read that I can swap in a 91 cluster but I was wondering if there is anything else I can do to get it to read properly.

I have already switched Pins 6 and 14 and the car is running great, I just want to get the Tach to read correctly.

 

[99talongsx]

Here is a 30 dollar Tylenol. DSMChips.com | DSM ECU Chips Enchanced by Keydiver

 

[Grip]

I thought they were out of business? I assume if the site is up and running they are back in business?

I just noticed all of the items arent in stock so I guess I was right in the regards to them being out of business still. Does anyone know of a company producing a similar product to make the Tach work in a 90 with a 91 ECU.