After Market Tach Options?

[mcgee]

Hi All,

First time posting here on the CS forum, but I'm hoping for some help on my '85 Celica GT-S 'Vert. I'm sure this has been discussed before, but hopefully someone can point me in the right direction for help.

I've got an 85 GT-S Convertible with an MS2 and LS Coils. I had a local shop and tuner install the MS2, and after it was done they let me know that the stock Tach on the 85 wasn't compatible. I'm looking for some feedback on what my best options are for aftermarket Tachs. I'd like to go in-dash if possible, but am open to attaching it to the column too. From what I've seen here, the CS dash from this era is identical, so I'm hoping I'll hear more from here than I did on my celica-gts post.

Thanks for any help/direction on this.

McGee

[CarFreek]

We will need more info, to give an intelligent response. Does the coil setup use an external ignitor/control module(Edis, GM HEI, etc)? How is the signal input sent to the MS, by modified distributor, or by a crank sensor/wheel? Depending on how it was configured, you may be able to use either aftermarket, or homemade tach signal adaptors to make stock tach work.

[mcgee]

We will need more info, to give an intelligent response. Does the coil setup use an external ignitor/control module(Edis, GM HEI, etc)? How is the signal input sent to the MS, by modified distributor, or by a crank sensor/wheel? Depending on how it was configured, you may be able to use either aftermarket, or homemade tach signal adaptors to make stock tach work.

Thanks for taking a look at this CarFreek...

The way we set it up, there is no external control module, and the signal comes from a crank trigger wheel. Does that help?

[CarFreek]

Without knowing more about your specific MS setup, I will hazard some guesses. First off, to the best of my knowledge, MS2 can only trigger coils directly on a 4 cylinder using a waste spark configuration-2 internal drivers for 4 coils. Each driver fires 2 coils at once. There are some homemade tach adaptor schematics on Toysports that may help you. Basically, each driver would feed a diode, those signals would be both inputted into the correct transistor, and a signal your tach could read would be produced. I dont believe any of the aftermarket tach adaptors will help you. http://www.celicasupra.com/forums/ar...p/t-20273.html Obviously, the schematics posted are for jz 6 cylinders, so just 2 diodes used for your 4 cylinder instead of of 3. Good luck.