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Tach Help

1K views 8 replies 5 participants last post by  TAGFoto 
#1 ·
After 11+ years of going just by ear, and with diminished hearing, I decided to get this tach just to set the idle speed. Don't plan to mount it permanently. https://www.ebay.com/itm/2-in-1-Dig...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Instructions say Black wire : Ground wire, connect battery negtive output (DC - ) Red wire: Power supply, connect battery positive output (DC +) Yellow wire : Speed signal cable, connet to ignitor outlet or trigger lines

My limited knowledge of electronics is sufficient to know where the red and black wires go, but where would you electrical gurus suggest connecting the yellow wire? I've read threads on other tachs where they just wrapped a wire around the spark plug wires. Would this work?
 
#3 ·
I'll agree with Guba
from the ad # 6. Installation guide :
"6.2.2 The high voltage ignition coil inlet wire (if car have no special speed line, we advise connected here)"

Inductive plug wire wrapped type is simpler method but they tend to cost a bit more..
 
#5 · (Edited)
I would think the easiest access to would be at the spark plug coil electrical connector..

Should be able to unplug one of the coils from harness and slip stripped wire into connector and reconnect wire harness as a temporary setup.. for a permanent connection I would strip back some insulation without cutting through wire from Blue/Yellow circuit and solder connection than seal with liquid tape..
 
#9 · (Edited)
Hi, I got a Searon digital tach on Amazon for $22. There are two models - one with a grounding wire and one without. I got the one without. It works great. I recently rejetted my carb and so my idle was high. I wrapped the black lead around my plug wire and it metered 1800 RPM. Two quarter turns on my idle screw (counterclockwise) got me to 1450. It took all of 2 minutes.
 
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