[kuhn-77]

I just replaced my tach becuase the needle would jump up and down constantly, it would only jump back and forth in about 250 rpms over what the engine was really running at, but my new tach is all over the place it will sometimes jump up past 6000 rpm at idle activating my shift light and everything even at idle it will nto go below 2000rpm it just jumps back and forth between 2 and 6 thousand rpm......any idea's.....its on a sbc, with Mallory HEI........could my wirring be wrong and somehow be doing this? if so what is the bast way and places to wire your distributor? any idea's? thnx guys

 

[Redlined]

Sounds like the tach isn't set right? Is there a setting for the number of cylinders, and 2nd, what vehicle is this? Electronic or are you using the ballast? Check your instructions carefully and go back over everything slowly. If you don't have instructions, search online and get them. Too many things can upset the balance... On that Mallory, there is a plug in on your cap, but that ran off an original? Was it originally HEI? I have the same distributor. Maybe I can get you a pic or 2 of what is connected at that end and you can see if yours is different? The car runs right? So I don't think you are plugged in wrong. Big plug then 2 small ones. One small one is a + and the other is your tach. Right?

 

[kuhn-77]

thnx i fixed it, i put on an accel super coil and it fixed my tach and it has better throttle responce.....that makes me mad though i kust spent like 50 bucks on the mallory HEI coil too that was like two months ago ...ohh well thnx for your help anyways