260z won't start due to no spark....Help please!

[Clomolina24]

Actually I just saw them above so I will follow them!

 

Thank you

[FastWoman]

FAIW, you might have a weak spark that is difficult to see, or you might have trouble seeing it in strong sunlight.  The starter fluid test would rule out quite a lot of things, and starter fluid is a very handy thing to have on your shelf.

 

Your points ignition system is pretty simple.  It works like this:

1. When you turn on your ignition, the + side of the coil receives +12V.
2. As your engine turns, the cam in the distributor turns, opening and closing your "points," which are a switch.  When the points close, they ground the - side of the coil, allowing current to flow through it.
3. When current flows through the primary side of the coil, a high voltage is induced in the secondary side.  Then when the points open, the interruption of current induces another high voltage.  There's another part, called a condenser, which interacts with the coil to generate a better spark.
4. The high voltage results in a spark that is routed via the distributor's rotor and cap to the correct spark plug.

Your coil should be good (new), but there have been cases of bad ones out of the box.  Your wires are probably good (new).  It's not a bad idea to replace the distributor cap and rotor on a vehicle with an unknown history.  Check your points to make certain they open and close correctly, and make sure that they are clean.  It's probably a good idea to replace your points and condenser anyway, BUT you have to know how to adjust your points and timing!  If you (or your dad) don't know how to do this, or if you don't have a dwell meter and timing light, then work with the points and condenser you have for now.  Check your wiring to ensure that the points ground the - side of the coil.  Check your ignition wires to make certain they run to the correct plugs and are in the correct firing order.  "Blue" has posted a nice diagram somewhere on this forum.  You might be able to search it.

 

Here's an illustrated discussion of how your ignition system works:

http://auto.howstuffworks.com/ignition-system4.htm

[EuroDat]

Sarah, I think his 260Z still has the original TIU. Well I believe it is, havn't seen any photo's to confirm it.

The manuals used the E12-05 and the automatics used the E12-06. The differance being in the automatic version with the dual pick-up in the distributor for the advanced timing in cold condition. A thermoswitch switches it over at a certain temperature, can't remember what...

I think clomolina has a manual, but Im assuming again....and that generally gets me into more trouble than good.

Chas

[FastWoman]

Ah, OK....  I saw the points replacement comment and forgot that the 260Z has electronic ignition.

 

Clomolina, try this:

1. Lift the wire(s) off the - terminal of the coil, turn on the ignition, and measure the voltage of the - terminal.  It should be +12V if you have not mixed up your wires.  The wires you lifted off the terminal should all be 0V.  If so, you're good.
2. Now reattach the wires to the - terminal, and add an additional piece of wire there.  Strip the opposite end of the wire.
3. Pull the coil high voltage wire off the center post of the distributor, and hover it over a ground point, maybe a couple of mm away.
4. Now turn on the ignition, and tap the bare wire (connected to the - post of the coil) to ground somewhere.  (DON'T TOUCH THE BARE METAL OF THE WIRE WITH YOUR FINGERS.)  As you tap the bare wire to ground, you should see a spark from the high voltage coil wire to ground.  If this happens, your coil is good.

Assuming your coil is good, now work forward:

1. Remove the extra wire from the - terminal of the coil, and leave the high voltage coil wire perched above the ground point.  Now crank your engine.  If you get a spark, the transistor ignition unit and distributor pickup is good.  As Chas points out, you might have the dual pickup system.  I forget.

Assuming you've got spark to the distributor, the question becomes whether spark gets from your distributor to the plug wires.  You might have a bad distributor cap (dirty/cracked/old/worn), which might be shorting your spark to ground.  IMO, you should consider replacing the cap and rotor for good measure.