What is the most common cause...

[Mat M]

:nervous: OK, now what?

I will still try to connect the hanging wire. I do not know if the previous 2 owners did any guage swapping. I know the PO tried to make an ignition ECU that was completely FU'd, as well as 2" tailpipes and header. hmmm.

[EScanlon]

...snip...I have changed the original dizzy with the ZX and the e12-80 module....snip.... I thought the tach was like the speedo with a sensor at the crank, or something...

Now that you have asked me those Qs, there is a loose wire from the loom with the wires that attach to the coil that comes from the passenger side...

[edit] no, I haven't noticed any spikes or play with the tach's needle at all

The Z's tach and wiring are just one of the wonderful anomalies you'll discover.

Arne's diagram is correct. However, what the diagram does NOT show, is that you MUST have the Green/White and Black/White wire that originally went to the resistor connected to each other. If that is NOT the case, then you'll end up with "extra" wires and a non-op tach.

With a non-op Tach and a SINGLE loose wire near the coil, that USUALLY means that you have TWO wires connected to the (+) terminal of the coil. This is true whether you have the electric dizzy or points.

If so, and one is a B/W and the other is a G/W, AND the loose wire is B/W then simply disconnect the G/W wire from the Positive terminal of the Coil and connect it to the B/W wire that's loose. That will complete the circuit on "RUN" through the Tach as it should be. The tach should now operate. If it does not, try swapping out the two B/W wires.

There should two wires to the (+) terminal of the coil and that should be a B/W wire (the return from the Tach) and the wire from the B terminal of the dizzy module.

If the LOOSE wire is Green with a White Stripe? And the two wires connected to the (+) terminal of the coil are BOTH Black/White, then you have to figure out which B/W is which for the circuit to the tach. This hook-up is entirely possible, the car will run but you've completely eliminated the tach from the circuitry...in the RUN mode, it will be operational ONLY during START.

This is more troublesome as it can cause problems if you hook up the wrong B/W to the Green/White wire. Hook it up ONE way and you'll have spark to the plugs ONLY when you crank, and the other way only when the key is in RUN.

I just checked MY wiring, but unfortunately it's all taped up because the P.O. had done such a "mahvelous" job of cross connecting wiring. (MY tach was non-op when I bought the car, which is why I'm personally familiar with this problem.) I did do continuity checks through the wiring from the module to the coil and tach with the ignition in RUN, not in START as I did not want to disconnect more wiring to keep the engine from starting. (Hard to do continuity checks with other electrical pulses going through the system.

But check it out and let us know what you find.

E¢

[Mat M]

The Z's tach and wiring are just one of the wonderful anomalies you'll discover.

Arne's diagram is correct. However, what the diagram does NOT show, is that you MUST have the Green/White and Black/White wire that originally went to the resistor connected to each other. If that is NOT the case, then you'll end up with "extra" wires and a non-op tach.

With a non-op Tach and a SINGLE loose wire near the coil, that USUALLY means that you have TWO wires connected to the (+) terminal of the coil. This is true whether you have the electric dizzy or points.

If so, and one is a B/W and the other is a G/W, AND the loose wire is B/W then simply disconnect the G/W wire from the Positive terminal of the Coil and connect it to the B/W wire that's loose. That will complete the circuit on "RUN" through the Tach as it should be. The tach should now operate. If it does not, try swapping out the two B/W wires.

There should two wires to the (+) terminal of the coil and that should be a B/W wire (the return from the Tach) and the wire from the B terminal of the dizzy module.

If the LOOSE wire is Green with a White Stripe? And the two wires connected to the (+) terminal of the coil are BOTH Black/White, then you have to figure out which B/W is which for the circuit to the tach. This hook-up is entirely possible, the car will run but you've completely eliminated the tach from the circuitry...in the RUN mode, it will be operational ONLY during START.

This is more troublesome as it can cause problems if you hook up the wrong B/W to the Green/White wire. Hook it up ONE way and you'll have spark to the plugs ONLY when you crank, and the other way only when the key is in RUN.

...snip...

But check it out and let us know what you find.

E¢

EScanlon...Now YOU are a Z GOD, too!

I had a look this evening, last night I couldn't get to her. It was a G/W wire that was loose, and there were two B/W wires on the + side of the coil! While I had the car running I disconnected one of the B/W wires, and nothing happened, I replaced that one, and disconnected the other B/W wire, and the car died. So, I am ciphering that the B/W that had no effect would be the one to connect to the G/W.

I am going out to try this remedy RIGHT NOW!

Thanks, BTW. You are Arne kick A$$!

[Mat M]

Still NO GO. I connected the benign B/W wire to the G/W wire to no avail.

The lights on the tach work, still. I guess that's a good sign. But now, it seems there is a ZZZZZZZ sound coming from the engine bay when the throttle is hit from idle. ALL the lights, including the headligts get real bright for about half a second during this ZZZZZZZ sound, and then all goes back to normal when the sound dissapears.

This tach seems to be stock, yellow line is at 6500 RPM, red at 7K.

I wish I had paid attention in electronics class. I lost my mind when they started talking about opamps and such...

I am at a loss...

[EScanlon]

...snip...While I had the car running I disconnected one of the B/W wires, and nothing happened, I replaced that one, and disconnected the other B/W wire, and the car died. So, I am ciphering that the B/W that had no effect would be the one to connect to the G/W.

...snip...

The "no effect" B/W is the one that goes to the coil in all cases, the one that killed the engine IS the one to connect to the G/W now that the resistor is gone. That's the initial power source for the resistor and then the tach.

As you have it now, the tach should be exhibiting "spikes" while starting the car.

Trust me on this, if you want a better understanding then continue reading.

When the engine is RUNNING (+) power from the battery goes through the fuse box and then to the ignition switch (via a W/R wire). From there it gets sent to the Resistor (via B/W wire #1) which then returns it to the Tach (G/W wire), the Tach then sends it to the Coil (B/W wire #2) and the system is energized and you can have spark at the plugs.

When the engine is being STARTED (i.e. the starter is engaged and running) the (+) power from the battery also goes through the fuse box, to the ignition switch (W/R). Here there is a "detour", the (+) is now sent DIRECTLY to the tach (G/W wire that receives the return power from the resistor), and from there to the coil (B/W wire #2 above). As you can see the fuse is totally bypassed.

When the engine is running the G/W wire FROM the ignition switch, used in the starter sequence is inop. The power gets returned to the G/W wire from the resistor and then to the tach. When you are starting the engine, the B/W wire that killed the engine when you removed it, is inop as the power is being sent DIRECTLY to the tach via the G/W wire and then the B/W wire that had no effect.

The power to the coil goes through one of two circuits BOTH of which go through the tach.

Hope this makes some sense. Trying to explain electrical circuits is tricky and can be very confusing.

As far as the "buzzing" that you're hearing, taking a WAG it might mean that your Voltage Regulator is having fits. But, with you having a couple of MAJOR wires (the B/W and G/W wires being mis-connected) let's first fix the problem with the tach, then let's tackle the VR...it might be that the buzzing goes away.

E

[Mat M]

Escanlon, I bow to you.

As usual, I was 100% wrong. I should just remember to do exactly opposite of what I think should be done.

I will try that fix tonight.

Since you brought up the VR, I have a ZX alternator, will I have to use a larger VR if I swapped it in?

I got another problem now. The last couple of times I have had the car warmed up, after shutting down, when I try to restart, I hear the solenoid click, but the starter does not engage. It's intermittant. Sometimes if I just hold the ignition all the way to the start position, it will engage the starter, sometimes not. Sometimes the starter will engage right away.

[jmortensen]

Mat why don't you try swapping in one of the other 40 or 50 starters you have and see if that helps the starting issue. You can usually clean the armiture inside and the contact points, but you've got so damn many why bother...

Search and I think you'll quickly find a guy who was selling a little wiring connector that plugs into the stock harness and then directly to the back of the ZX alternator which is internally regulated IIRC. You don't have a big stereo or any of that yet, so for right now what you've got (40 amp) should be fine.

[Arne]

Search and I think you'll quickly find a guy who was selling a little wiring connector that plugs into the stock harness and then directly to the back of the ZX alternator which is internally regulated IIRC. You don't have a big stereo or any of that yet, so for right now what you've got (40 amp) should be fine.

That'd be me, if I was really doing it. But I ran out of time before I actually got the first batch made. I plan to build some eventually, but right now I've got too much going on with my own car to find the time to build and ship these gadgets. Maybe later this summer, if all goes well.

[EScanlon]

...snip...

Since you brought up the VR, I have a ZX alternator, will I have to use a larger VR if I swapped it in?

I got another problem now. The last couple of times I have had the car warmed up, after shutting down, when I try to restart, I hear the solenoid click, but the starter does not engage. It's intermittant. Sometimes if I just hold the ignition all the way to the start position, it will engage the starter, sometimes not. Sometimes the starter will engage right away.

Arne will be your best info source on the ZX alternator, I've not worked with one and would be hesitant to even hazard a guess. But that being said, here's what I recall about the ZX alternator....they're internally regulated, as such you need to eliminate the external regulator on the side of the engine bay. Again, ask Arne, he was in the midst of making some form of plug to connect it into the older wiring harnesses, but had hazzles in getting the proper connectors.

As far as the "starter malfunction", it isn't your starter.

It's in the ignition switch.

The solenoid you hear clicking IN the passenger cabin is the ACCESSORY relay that is being energized when your switch is in the "RUN" position, and off when the switch is in the "START" position. This is the relay that powers the fog lamps, rear window defrost, and other accessories (fan, radio, etc).

The STARTER Relay is on the Starter itself, I'm not sure you could hear it very well from inside the cabin. (Hey, maybe you can!)

But, and here's the kicker, I also have this problem, and it IS the Ignition Switch.

Attached to the back of your Steering Wheel Lock is the Ignition Switch. These have a funny habit of getting loose, and not making good contact when actuated. It isn't that they're not MOUNTED onto the lock properly, it's that they are a rotating switch, and internally they get sloppy..INSIDE.

But, thankfully, there are switches available, since Nissan used the same switch in various models. I'm having computer "fun" so I can't look up the part number, but if you have the club's microfiche you should be able to get the part number and call your local Nissan dealer.

Taking it apart is EXTREMELY difficult and putting it back into operation afterward would probably border on the impossible. The switch components are crimped onto the switch body and it's that same "pot-metal" type body that resists any kind of bending.

If you check your switch you'll probably find that like mine, the electronic contacts in the bake-lite, are not being held firmly in place by the surrounding metal collar crimp. As a result, the bake-lite can rotate slightly and it does, which makes for a poor contact when you rotate the switch via the key. I guess you could try gluing the bake-lite in place but I've not tried that yet.

Hope this helps.

Enrique

[jmortensen]

I've had starters fail in that same way that Mat describes and have fixed them by cleaning the armiture. I don't think we have enough info to say what the problem is yet. He does have 50 starters though, and it's 2 bolts and a plug or two to swap them out.

I've also seen the switch go bad on a number of Z's, so that is a good possibility too. I just wouldn't rule out the starter yet.

[Mat M]

Thanks to all, especially to JM who reminded me...

I guess I will be trying one of the 400 ignitions I have. Is there a way to re-key an ignition so I can have only one 4 inch key on the ring that will work with all the locks?

[jmortensen]

A locksmith should be able to re-key a lock.

The iginition switch is separate from the lock cylinder though. The switch unscrews off of the back of the cylinder. If you look at the back of the lock, the key goes all the way through and sticks out the back of the lock cylinder, and it's that last 1/4" of the key that twists the plastic switch.