shakey tac
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 807
Likes: 2
From: VIRGINIA BEACH VIRGINIA
shakey tac
I have a 1979 L48. When I am cruising down the road the tach sometimes start jumping all over the place from 2500rpm up to 4000+rpms. Not sure why. It is mainly when I am stepping on the gas. I checked the wire going from the dist to the tac and it seems fine. Not sure what it could be. I took the top cover of the dist off and it looks like a big coil there. that is what the tac is connected to. The wires and plugs are new. Any ideas? Thanks.
Le Mans Master
Joined: Jan 2007
Posts: 7,999
Likes: 3,338
From: Omaha NE
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2022 C3 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
Start here & you might get lucky. I got a bad connection after I painted the intake & didn't scrape the mounting spot clean.....
Intermediate
Joined: Dec 2008
Posts: 47
Likes: 0
From: cary nc
i have a 79 L 48 and i had a jumpy tach for years. i tried a new tach circuit board and that didnt work, actually made it worse. i wired up a temporary 2nd tach i had laying around and it would jump also. i played around with different coils and modules seeing if that would help, but no luck. a guy at work tried to tell me that something wasnt right with the distributor. finally, i broke down and purchased a new pertronix flame thrower hei distributor and the tach needle was rock steady. i guess something electrical had broken down inside the distributor after 30 years. good luck.
