Hi.
My tach intermittently stops working and when it does I get a beeping from my dash area when I start to move, not when I'm sitting still. I can turn the car off and start it again and the tach willl start working. I've tapped on my instrument cluster to see if it would help but it didn't. I 've read about a wire going to the trailing coil that might have a intermittent connection? Where's the trailing coil? any oher ideas out there that could help me?

 

Hard to say without knowing what car you have, but I would bet it is the power steering computer, since it needs a tach on some years.

Trailing coil is the one at the rear of the engine compartment, near the brake and clutch masters.

 

Hello Icemark. I've got an 87 non-turbo. You helped me in the past with a logicon problem . I don't mind the tach so much not working but the beeping can drive me insane. I'm guessing that the power stering cpu is in the dash?

 

yeah the power steering computer is located right behind the drivers dash speaker. Silver box mounted on a really long angle bracket.

If you have a digital multi-meter you can check the tach signal coming from the coil and at the power steering computer (and dash). It will be a yellow/blue at all those locations.

With the meter set on AC voltage, and the negitive terminal of the meter grounded, you should see about 2.5 volts AC go up or down as the engine revs up or down when probing the positive lead of the meter into the connectors on that yellow/blue wire.

If you don't see any voltage change your trailing coil may not be firing. You'll need to fix that for the engine to run cleaner.