Ignition / Tach

[pbtv]

Hi folks!

A while back my tach started jumping jumping around. Eventually, it just stopped working. I wasn't too worried about it, but now im chasing down the problem. I opened up the dizzy and had a few questions in the attached photo.

1. The FSM does not name what the "floating" thing is in the attached photo. I assume its some sort of junction for the wires leading into the dizzy. How/where does this attach?

2. One of the wires coming from the dizzy (blue, circled) was just bare. I could not find where this goes and the FSM wiring diagram left a lot of questions.

Thanks for any help; Im tripped up on where these go. Anyone have a photo of their setup? anyone solve a dead tach before?

TIA!

tercel_tach.jpg

[Petros]

the first item, the floating thing is an electrical condenser. it gets mounted on the screw that holds the cap in place (one of three screws w/8mm hex). it is required to run, it acts like the equivalent of a damper to prevent arching when the coil field collapses to create a 20,000 volt spike for the spark plugs. The condenser just needs to be attached to a ground point, and the distributor cap screw is the easiest place to install it.

The other blue wire could be the tach signal wire. it is hard to tell in the photo. There should be a large green barrel connector from the distributor with two wires, that plugs into a mating connector that goes into the wire harness. One supplies 12 volts when the ignition switch is in "run" and "start" position, it powers up the ignition system. The other wire is the tach signal wire. It will run without the tach signal wire, not without 12 v. to the other wire.

There is also another connector i think a test plug, or something. It is not used. Every tercel I have seen with this distributor has a cover over the end of the second connector. And I have seen a lot of them.

[pbtv]

Thanks, Petros! I figured the condenser attached on the hold down screw, but didn't want to ground it in case it did not. That third "blue" wire most likely is the test port you speak of. After looking at pictures of dizzy's from various other 3A's, that test port comes out of the same harness that connects the dizzy back to the fuse box, as this wire does. It looks like the p/o probably broke it off or lost it somewhere. At any rate, it has power for a while when the ignition is turned on.

We'll see if grounding the condenser is what the tach needs when i get home tonight.

[garyfish]

pbtv, did you resolve your tach issue?

if so, would appreciate you posting here what you found out