EDIS Tach?

[woodsbuggy1]

I am running MS1v2.2 with EDIS and have my tach hooked to the tach wire from the EDIS module but it doesn't work. What do I need to do to have a properly functioning tach?
Thanks
Kenric

[Piledriver]

It depends on the tach...
You need to know if the tach can or needs to be hooked up directly to the coil...

there are basically 2 (maybe 3) setups that work on older and factory tachs that need the HV kickback from a coil to work:
1)msXextra programmable output and a "fake" coil, using a relay coil and a diode and a driver transistor.Scroll down a bit to the one with the relay coil.
http://www.msextra.com/doc/ms2extra/MS2 ... m#tachoout

2)Array of diodes (2 in this case) directing all the kickback pulsed back to a common point without shorting all the coils together. Needs a tach expecting waste spark. This is also buried in the msextra docs somewhere near the previous one.

3)Hook up tach directly to one of your EDIS coils - side. I'm thinking it's firing on compression and exhaust on 2 cylinders is the same # of firings as a std 4 banger single coil setup would deliver, but it's late.

Big Fat Warning:
The above idea just occurred to me, I have never heard this suggested, and I haven't tried it (as I don't run EDIS) and seems way, way too easy... May also be done all the time.

[Clonebug]

Hey Kenric,

Which pin are you hooked to on the EDIS???

I had two different tachs that worked just fine off of pin #2 on my EDIS module.
One was a Sunpro 2 1/16th inch el cheapo tach and the other is an anniversary tach put out by "MAC Tools" at least fifteen years ago.

The funny thing is I can't get either one to work on my wasted spark MS-2 Ver. 3.0 even after using the tach adapter you can purchase that hooks to both coils.

[miniman82]

IDM pin on the module has worked for me so far, even ran the factory dash tach in my Corvair that was previously wired to the coil.

[woodsbuggy1]

Thanks for all of the input guys. I am currently hooked to pin 11 CTO, which I thought went to the tach but I will try pin 2.
Thanks Again
Kenric

[Clonebug]

Now I have to think about it.........it might have been pin eleven.....I'll go look for my wiring diagrams if I wrote it down.......

[andy198712]

http://www.shoptalkforums.com/viewtopic ... 3&t=140215

try this

[jhoefer]

3)Hook up tach directly to one of your EDIS coils - side. I'm thinking it's firing on compression and exhaust on 2 cylinders is the same # of firings as a std 4 banger single coil setup would deliver, but it's late.

You'd only get 1/2 the rpm reading doing that. Unless your tach has a 2-cylinder mode. This is the reason you need to connect both coils together with diodes from your option #2.

[Clonebug]

I verified my wiring and I did have it connected to the #2 pin.

Pins #1 and #3 are the pip and saw wires and #2 is tach.

[woodsbuggy1]

I think that my tach is bad, doesn't work on pin 11 or pin 2. Have a new one ordered.
Thanks
Kenric

[woodsbuggy1]

Finally got my tach working on pin 2 after I repaired a bad connection .
Thanks for all of the help
Kenric