tach options....what to do :( [Archive] - SaabCentral Forums

: tach options....what to do :(


1oldsaabman
15th April 2006, 09:49 AM
Here's my situation, my 88 SPG has a autronic ecu with a MSD DIS-2 direct ignition. Unfortunantly the MSD is to powerfull for my saab tach thus above 4K or so it freaks out & goes dead. So I need to add something else to the car & I have no clue what to do or where to put the $#%ing thing. Any suggestions/pics?

speedysaab
15th April 2006, 10:25 AM
which autronic are you using?

on the sm4 theres a tacho output that you can plug upto where the ignition amplifier used to be - have you tried this?
otherwise id leave a post to rayhall on the autronic forum

1oldsaabman
15th April 2006, 02:05 PM
I have the older SMC :( Still a great ECU just not as great :)

That's a good idea to throw Ray Hall a question, totally forgot about that & I purchased it from him :)

900t
15th April 2006, 08:26 PM
Here's my situation, my 88 SPG has a autronic ecu with a MSD DIS-2 direct ignition. Unfortunantly the MSD is to powerfull for my saab tach thus above 4K or so it freaks out & goes dead. So I need to add something else to the car & I have no clue what to do or where to put the $#%ing thing. Any suggestions/pics?

Put a resistor in the line or something.

1oldsaabman
15th April 2006, 10:58 PM
we tried a handfull of different resistors with no luck

then tried the MSD parts which caused the ECU to not work at all

I just talked with someone who deals in autronic ECU's & he stated there is a autronic resistor that might work, I didn't know there was such a thing. So he's going to try to find it & stated that this should do the trick.

fingers, arms & legs are crossed :o

Boosted Shoe
16th April 2006, 12:51 PM
Aside from that you could just put in one of those big 5 inch tachs. Some places also sell small 2 1/16" tachs. I'd be interested in knowing if that resistor actually works. Keep us posted.

ejenner
17th April 2006, 05:42 AM
Normally the tach is driven by the ignition module. Pin 7 IIRC? Couldn't you find a way to re-connect the ignition module so it drives your tach? Maybe you could feed the signal from your autronic through the ignition module? Into Pin 1 maybe?