BOLO

iTrader: (40)

I don't know if this is the right section for this specific tech question, but any info is appreciated. I did the LS1 pcm conversion for my LT1 and wanted to wire my AutoMeter#3980 tach. Since I'm now running multiple coils, what cylinder do I set the tach for?(involves cutting some wires back of tachometer)And where do I get tach signal from? Any suggestions is greatly appreciated. Thanks.

fastgmc98

iTrader: (15)

I usually just hook up green tach wire to PIN#10 on Red PCM connector...
Never had to cut any wires...

BOLO

iTrader: (40)

So, the tach is then set for 8 cyl? 4cyl? 6cyl? Need more info here

Doubledip

4 cyl

BOLO

iTrader: (40)

Thank you. 4 cyl it is.

408tony

How do you set it for 8cy or 6cy or 4cy?

oange ss

iTrader: (50)

should be DIP switches on the back of the tach to set the cyl mode

BOLO

iTrader: (40)

Just an update info on this. I did not have to cut or adjust anything on the back of the 5" tach #3980. Works flawless.

LS1MCSS

iTrader: (18)

A lot of Autometer tach's have two wires looped out the back of them. Depending of what cylinders you want it set for determines if, or how many of the wires have to be cut apart.