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intermittent tachometer issue

Started by the_kirkwood, December 03, 2019, 03:43:20 PM

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the_kirkwood

December 03, 2019, 03:43:20 PM
Tachometer is bouncing erratically at idle.  When riding it normally drops to zero rpm with some random twitching from time to time.

Is this likely to be a bad tachometer, bad signal to tachometer or maybe a bad ground?

Is it common for these tachometers to go bad?

thanks in advance
1986 fj1200

FJmonkey

#1
December 03, 2019, 03:55:30 PM
The ground connection is almost always the issue.
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

the_kirkwood

#2
December 03, 2019, 04:10:11 PM
Right on.  Thanks
1986 fj1200

Pat Conlon

#3
December 03, 2019, 04:46:40 PM
Also to check is the grey signal wire coming off your right side #2/3 coil. Clean that connection.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3
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