Weird Tachometer problem in a 1993 Tercel

[bumedout]

I have a 1993 tercel which runs like a champ. Some time ago i acquired a tachometer for free. I installed it and the tach worked just great until my dad decided to replace my distributor cap and spark plug wires. Since then the Tach will only work for a couple of seconds once the car is turned on. Then it usually stays constant at 1000 rpms and then at times randomly spins around. The reader is clipped to the spark plug wire not to far from the distributor cap. I noticed that the new spark plug wires are noticably thicker than the old ones (i"m not sure if that has anything to do with the problem). I really enjoyed having the working tach even in my old beat up 93 tercel, if you have any ideas please share them. Thanks.

[bkftl]

spark plug wires inside are two wires

Fatter = better insulated

Did i read that right you CLIPED IT? Without actualy cutting the insulation or wire?
why not simply splice into it? Make sure u get the right wire...
or splice into the distributor box for the electric signal

You will have to re-insulate the wire though.


Ive heard of a wire with a special port for instaling a tach liek that i think.

I hope that helps

Im still working on my tercel. I plan on putting a Tach in too. Yeah retarded that it doesnt come with a TACH.

[WilliamRobert]

A little off topic, but I just went to Pick-and-Pull and got a gauge assembly from a wrecked paseo that had a factory tach and switched it out with my original that did not. Cost 20 bucks, and took only 20 minutes to do. The wiring harness's are exactly the same and now it looks like my '91 Tercel came from the factory with a tachometer. The only difference is that the mileage were on the new one was 20,000 km less than my original. But with over 400,000km, I don't think that it hurt my resale too much.
Food for thought.

[SR20DETT]

If I read that correctly it sounds like you have a tach with an inductive pickup. If that's the case the insulation may be too good on the new spark plug wires for the inductive pickup to read the signal. This happens with my timing light sometimes so I keep a crappy old spark plug wire in my tool box. You might want to investigate if that tach has the option for a direct connection then you can just tap right into the negative side of the coil right at the distributor.