Tachometer Hook-Up to HEI

[HG72]

I am restoring a 72 Chevy Truck, I am having trouble hooking up my stock tachometer to a new HEI distributor. Every time I connect the Tach. the truck will not start when I disconnect it starts up just fine. Does anyone know what might be happening here, is there some trick to this hook-up?

 

[2tons of fun]

check your dist to cap plug, the 3 wire that clips in to the cap, you may have it backwards.

the tach works of ground signal, when yours shuts the truck of you are shorting the power straight to ground.

is the dist the only thing you did or have you added/replaced some other stuff?
did the tach work on the last dist?

 

[HG72]

Hello 2tons of fun,

Please explain quote: check your dist to cap plug, the 3 wire that clips in to the cap, you may have it backwards.



When I bought the truck the engine was blown (small block 350) it was all original including the original tach, it was hooked up to the original point system.


I since have had the engine rebuilt and had an HEI distributor installed, I also replaced the wiring harness with a painless kit for the exact year of my truck, it included a single tach wire connection with this kit. I hooked up one end to my tach side on my disributor cap and the other end to a brand new exactly the same tach I also purchased , which has a two clip connection backside to it. I have plugged it into both sides and what happens is on one clip side the enging starts up fine but no Tach , on the other clip when cranking the engine I get tach movement but the engine won't start. I have also tried groundng the opposite clip in that same scenario and got the same results. I am also having no luck with my gas gauge ( relocated gas tank), which is on another post here might they be related?

ps- I do have sufficient grounding throughout my truck!