260Z Will fire with starter, quits when key is released.

[Jeff Z]

74 (early) 260Z, It turns over fine and will fire when started is engaged. As soon as the key is released it dies. I heard this may be the ballast resistor. Any  suggestions would be appreciated. I need to get this car winterized, but must get it to run again, before that happens.

Edited November 24, 2018 by Jeff Z
misspelled word

[SteveJ]

Do you have a multimeter or test light?

[SteveJ]

PM sent

[Mark Maras]

 I'd look into the ignition switch first. That's a common symptom when they fail.

[SteveJ]

With a multimeter or test light it would be easier to check at the ballast resistor first.

[Jeff Z]

44 minutes ago, SteveJ said:

Do you have a multimeter or test light?

Not accessible to me right now, so no. Do you suggest I go get myself one?

 

 

Edited November 24, 2018 by Jeff Z
added to message.

[Jeff Z]

44 minutes ago, Mark Maras said:

 I'd look into the ignition switch first. That's a common symptom when they fail.

Is there a way to test the switch?

[SteveJ]

Get at least a test light.

Turn the key to On.

Clip the wire on the test light to chassis ground. A common point is one of the bolts on the shock tower.

There are three wires on the ballast resistor: white/black, black/blue, and black white. With the key in the On position, you should have voltage at the black/white wire. It has the arrow next to it in the picture

Lift the cap on the black/white wire and touch the pointer of the test light to the wire.

If the test light lights up, lift the cap on the white/black wire (opposite side of the resistor from the arrow) and touch the test light to that wire.

If you didn't have a light on the black/white wire, you have a loose/bad connection or bad ignition switch. You might want to talk to me on the phone about tracking that down.

If you have a light on the black/white but not on the white/black, you have a bad ballast resistor. You can move the black/white wire to the same terminal as the white/black, but you shouldn't run it long that way. 

[240Znomad]

I had the same problem on my '71 240Z.  Car would crank and start fine but as soon as I let the key return to the "ON" position it would die.  I replaced the ignition switch thinking that was the most likely source of the problem but it didn't make a difference.  I finally tracked it down to a loose/dirty connector on the ballast resistor.   I removed the connectors, cleaned them real well, and made sure they were nice and tight when I put them back on and everything works fine now.  I believe on the 240Z the ballast resistor is bypassed when in the START (ie. cranking) position but comes into play when the key returns to the ON position.  I haven't looked at the 260Z electrical diagram but I would imagine that it might be similar.

[Jeff Z]

Thanks for the help! I'll let you  know when I am able to try out the suggestions.

[Jeff Z]

I finally got time to get back out there and it turns out one of the posts on the resistor is loose and comes right out. I am assuming this is the problem. Does anyone know where I can find a replacement for this resistor? Or should I do an upgrade?

Jeff

[SteveJ]

The 260Z ballast resistor is NLA. You might be able to get away with a 240Z ballast resistor. You would have to move the start wire over to the same terminal as the coil wire. 

The problem with that is that I don't know why they introduced a small amount of resistance in the starting circuit. If you're worried about that, there is a kludge I could describe to you, but it's not very elegant.