Topic: Tachometer Problem

[78blkice]

I put a new water pump on my 1978 Y88 (that part went perfect), however, when I reattached everything (alternator followed by the battery) and fired her up, the tachometer was not working.  It was working fine before the install. Could something have gone wrong or is it just a coincidence?  The funny thing is when I turn the key on, the needle goes from 500 back to zero then won't move off of zero while she is running.  Any help would be greatly appreciated.

[oreobadr]

sometimes this happens to me, and i just give her a quick rev, and its restablizes, also you can open the wire attachment near the motor and clean it with some electrical cleaner

[78blkice]

Thanks oreobadr.  Which wire attachment are you referring to?  Thanks again!

[eroc022]

green wire connected to the distributor

[brian c]

Actually it would be a white wire running to the distributor (brown plug if I recall) that connects to your tach.

The green wire Evan is referring to is for engine temp

[eroc022]

Actually it would be a white wire running to the distributor (brown plug if I recall) that connects to your tach.

The green wire Evan is referring to is for engine temp

sorry for some reason I was thinking VW engines.... oops..

[78blkice]

I appreciate the feedback.  Everything is checking out with the wires.  I just cant figure out what is making the needle go backwards when the ignition is turned on.  The day goes on =)

[eroc022]

does it do it while the engine is running or only when you turn the key on? might be a voltage spike......

[brian c]

Try this....run a dedicated ground (from lets say your parking brake assembly) to the GND terminal on your gauge cluster. Now try your trach again.

I ran into an issue where my tach wasn't getting a good ground and it acted the way you mentioned. Once I ran the ground, it worked.....or at least for me