My 280Z cranks but doesn't stay running once started

[K Koehn]

On 1/25/2019 at 7:00 PM, Zed Head said:

Check the little yellow wire to the starter solenoid.  It might be loose or disconnected.

You're standing right there by the coil with the key on.  Might as well take a measurement.  Sometimes people take the same measurement multiple times.

I checked that wire on the top of the starter and its was on tight, but it looks like my ignition coil is leaking now and the + and - sides aren't reading any voltage across eachother twice and the test light showed no power to that yellow wire going to the starter as well in the on position

Edited January 26, 2019 by K Koehn

[Zed Head]

The yellow wire only gets power when the key is turned to Start.  No power there when the key is on.  No offense, but you need to go through the sequence of how things work.  It will help your troubleshooting efforts.

Sounds like the points might have been closed when the key was on, or the points distributor is wired incorrectly with constant power, and the engine stopped with the points closed.  Looks like you overheated the coil.

Voltage is not measured across + and - , it's measured from + to ground, and - to ground.

You're making progress.  Good luck.

[K Koehn]

11 hours ago, Zed Head said:

The yellow wire only gets power when the key is turned to Start.  No power there when the key is on.  No offense, but you need to go through the sequence of how things work.  It will help your troubleshooting efforts.

Sounds like the points might have been closed when the key was on, or the points distributor is wired incorrectly with constant power, and the engine stopped with the points closed.  Looks like you overheated the coil.

Voltage is not measured across + and - , it's measured from + to ground, and - to ground.

You're making progress.  Good luck.

Ok, thank you

[Jughead]

@K Koehn:  Did you resolve this issue?  I'm having the same issue with a '72 Z running carburators.  Mine starts for a second then stops.  I"m getting no spark when I turn with a remote starter, BUT when I start with key, and hold the key on the START position it runs.  Ignition switch issue?  How would I diagnose this?    

[SteveJ]

28 minutes ago, Jughead said:

@K Koehn:  Did you resolve this issue?  I'm having the same issue with a '72 Z running carburators.  Mine starts for a second then stops.  I"m getting no spark when I turn with a remote starter, BUT when I start with key, and hold the key on the START position it runs.  Ignition switch issue?  How would I diagnose this?    

Likely suspects include the ballast resistor, tachometer, and ignition switch.

This diagnosis assumes the car to be stock. Put the key in the ON position. Use a voltmeter to measure voltage to ground at each terminal on the ballast resistor. If one side does not have voltage to ground, replace the ballast resistor. If neither side has voltage, the problem is with the module in the back of the ignition switch.

If both sides have voltage, then lift the negative wire off of the coil. Measure voltage to ground on positive side of the coil. If you do not have voltage, the problem is the tachometer. Check to make sure the tachometer is firmly connected to the dash harness.

[Zed Head]

Here's an old thread about problems with the ignition switch.  Test at the ballast and coil first like SteveJ says, if there's no power there, work your way back.

 

[Jughead]

@SteveJ:  Thanks for the advice.  I measured the resistor at both sides  No current.  So I swapped the module in the back of the switch with a "new"  module from an old ignition switch that came in a box with the car.  Same result as originally described - no voltage at either resistor terminal and same (non) starting symptoms.  What would you try next?  A new module?

Thanks!

[SteveJ]

What do you mean by "no current"? I asked you to check voltage to ground. How do you know the swapped module is good? Could you tell if the key was turning the module?

[SteveJ]

And if you're wondering where to get a new ignition switch (back portion)

https://www.rockauto.com/en/catalog/nissan,1972,240z,2.4l+l6,1209169,electrical-switch+&+relay,ignition+starter+switch,4700

[Jughead]

Update:  Found a broken female spade connector om wire to resistor.  Renewed it and now I have voltage to resistor....and the car runs nicely...THANKS!!!

[K Koehn]

Hello everyone, my apologies for not concluding on this issue, My issue ended up being the EFI control module itself, as well as a short near the ballast resistor. I hope this helps anyone in the future.

[SteveJ]

4 minutes ago, K Koehn said:

Hello everyone, my apologies for not concluding on this issue, My issue ended up being the EFI control module itself, as well as a short near the ballast resistor. I hope this helps anyone in the future.

I thought you said it was a 72. That year doesn't have any EFI components.