I have an intermittent problem with the tachometer on my 1985.
At times it works fine, then just goes to zero, stays there for awhile and then reads fine again. Does not work at all when the car is up to operating temperature. Works during warm-up.
I checked the connections at the coil, in fact replaced the coil with an Accel unit, no change.
Have any of you been through this problem?
Submitted by: Thomas Shusko
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Test the tach output from the ignition module. Later model cars do not use the coil as the tach output but rather rely on a circuit in the ignition module which is much more accurate. If the output signal from the module is good recheck it where it goes into the computer or the back of the instrument cluster. Some signals go to the car?s computer where they are used for various rpm control functions and copied and forwarded to the tach while others go straight to the tach.
If you have a good output from the module and nothing at the back of the cluster or computer (depends on configuration of your system) then look for high resistance somewhere between the two points. But if you have a good signal all the way to back of the cluster unplug the cluster and treat the wire connector with a contact enhancer and retry. If it works you?re golden if it doesn?t start shopping for a cluster repair.
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Posted by Administrator on
2/5/2014 3:49:12 PM
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