car: '87 TII

recently I'm experiencing this symptom more frequently.
i'll start the engine but no tach.
however the tach will come back to life, e.g., if while coasting in gear i turn the ignition off then back on.

is there an explanation?

 

First thing to check would be wiring...sounds like a loose connection or frayed wire.

 

do i check around the leading or trailing coil?

 

Had this happen on two different cars, checked all connections, repluged connections, did not help. Replaced Rear coil pack and the problem was gone.

Good luck

 

I had bad Trailing plugs that would do that too.
Fouled up and lost tach reading.

 

thx 4 the suggestions.

If no tach means the trailing side is not getting getting spark, should the engine idle be weaker. e.g., lower vacuum? I'll have to hook up the timing light on the traing side to see if there is spark when the tach is dead.

 

Check grounds?

The one for the instruments is under the trailing coil I believe.


http://www.aaroncake.net/rx-7/grounding.htm

 

thx 4 the excellent link

 

Most likely either the tach itself or the trailing coil. As cheap as both are, I'd pick up known working used ones and try them out before I started spending my time in the wiring aspect.

You can get an NA cluster and use the tach out of it...you can even just plug it up to your turbo car and see if it behaves better before swapping the individual tach itself into your turbo cluster.

 

Mine was a Bad connection by the harness near the brake cyclinder

 

I thought the tach was related to the trailering rear coil? Fouled plugs, severed ignition wire, or faulty coil pack would cause the tach to be in and out intermittently

 

I thought the tach was related to the trailering rear coil? Fouled plugs, severed ignition wire, or faulty coil pack would cause the tach to be in and out intermittently