Bouncing Tach
Thread Starter
Intermediate
Joined: Mar 2005
Posts: 49
Likes: 3
From: Anderson, Indiana
Bouncing Tach
I have a 67 390 and the tach needle has suddenly started to bounce. It seems to be most prevalent when decelerating and revving the engine. At idle and constant speed it's fine. I know I have seen others on the forum with this problem in the past but I wasn't able to find anything in a search. Any suggestions on a cause/fix would be appreciated.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Yank the distributor and unscrew the coupler - if the cross gear and mainshaft gear look like the photo below, it's time to replace them both. If you only replace the cross gear, the new one will be eaten up in no time. 
Pro
Joined: Mar 2001
Posts: 608
Likes: 4
From: houston, texas usa tx
I am pretty sure I have this problem. Everything behind that distributor is new or been redone. I think I will unhook the cable and spin the cable with a drill to see if the tach needle moves normally. Then yank the distributor if that needle moved normally with the drill.
