tachometer 81 ohm specs problum

[gravismaximus]

i have had a very big problum and i know people will say no, not possible but it is i tell ya. any way ill be driving my 81 and outta the blue my tach goes to 0 and my car dies (same time) while im coasting to a halt becuase it died :ugh sometimes it will come back to life tach jumps to say 2200 and enginge starts to run again:confused . been happing for 2 years now. one day as i was getting to work it died on me and i had, had it. so i tried to figure it out, i put a test light on my tach wire at the cap and started the car, test light lit up and when car died so did the light. ok heres the part that gets me ?????? somtimes the car wont start back up again after i come to that very furstrating halt. this was one of those times. out of pure intrest i unpluged the tach wire at the cap and it fired up and ran fine. as soon as you put it back on it would kill the car:crazy , just like if i was going down the road. so im pretty sure it is my problum somehow in the tach circut. simple fix was leave it unpluged and i didnt have a problum. got a new job and my guru boss said the tach has nothing to do with my spark (reason its dieing) and we pluged it back in, about 2 months later my ign moduel died got very weak so the spark signel it put off wasnt enogh. replaced the coil and the moduel, ran good again for about 2 months and i need a new moduel again. screw this unplged the tach again no problums scince. diffently has somthing to do with tach. so i checked the tach ground, have replaced the tach wire, check and recheck connections. ?????? for chirstmas i got a new printed curcit (tach), a tach filter (didnt have one befor oem??) a ign moduel. and will try again. will be getting a new tach and board. anything else in the circit im missing? however i do want to test my tach, what are the ohm readings for the tach itsself not the board.
this all started when i tried to install a autometer tach and ended up saying forget it becuase of the mods i would have to make and i made a short to power err ground on the board testing it outta the car.:W i went and had the board fixed, and it does work but i suspect it being the problum (started when i had it fixed)
i know the tach should not be able to short out my moduel but it is. there is no computer on the car i use a 4 pin moduel. any other insight would be nice just in case ive overlooked somthing.:cry

 

[bill81vette]

If you plug in your tach,the vette quits? you plug it back in and have a poor spark,or no spark?
seems to me something is wrong(shorted out or shorting out)in the distributor.I would start there.take the coil out and check to see if there was any arcing,burning,melting inside the top of the distibutor.

 

[gravismaximus]

ive done that also, took apart like i said and replaced the coil, saw no signs of arcing, melting, etc... wires and the coil. i have also replced the hole distributor after it started to happen the first year. there is one thing that ive noticed with it----even with the stock distributor it wears at the dis cap button weird. takes some of the plastic around it with it, not alot but enough to notice, before someone recomends it i have replaced the cap as well....... is this common for vettes to do with hei and why?? anyway thanks for at least asking.