1974 260Z electronic ignition control unit help

[Shawninvancouver]

Can   this unit be tested?  are there any after market units i can get that will just plug in?

does this look fried?

i get power to coil but cant get spark, is this the culprit?

 

thanks

[Shawninvancouver]

this is on ebay but the last number in the part is different.. what is the difference in these 2?

thanks

[Zed Head]

Yours looks in pretty bad shape.  But even the eBay one is old and could fail at any moment.  Probably easier to wire in a GM HEI module.  The eBay module might be from a 75 280Z.  Looks like it would work though if the wires are the same.

Here's a couple of links about the GM HEI module.  No offense, but, considering your problems with plug wires I'm not sure you'll get the wiring correct.  Be careful.

https://www.classiczcars.com/files/file/64-1977-280z-replacing-the-tiu-with-a-hei-module/

 

 

[SteveJ]

I'm not sure if the connector on the other TIU lines up. Do you feel adventurous enough to modify the ignition? With an HEI ignition module, a couple of diodes, a heat sink, heat sink paste, and a connector from Vintage connections, you could make a replacement ignition unit that would be pretty darn reliable for about half the price of that TIU you have in the last photo.

(@Zed Head are saying the same thing.)

Here is how you would wire the HEI for the TIU connector in the 260Z with the 6 pin rectangular connector. (Edit: Changed for the revised diagram in my later post.)

Note: the connector as I have is drawn is a mirror image to the connector shown in the FSM wiring diagram per the Nissan drawing practices.

 

Edited June 6, 2021 by SteveJ

[Zed Head]

If he wires it in the engine bay then he can just use the red and green directly to the W and G pins, B from the coil's + terminal, and C to the coil's negative terminal.  Then unplug the module in the cabin.

That's the quick and easy test method if a person is not sure the module is bad.  If it works, then it can be moved to the cabin.  Or not.  

That's a nice diagram for in-cabin mounting.  You could make a pdf and ask Mike to put it in the Downloads area for 260Z applications.  @Mike

P.s. are the diodes necessary or is that your engineer side saying that they couldn't hurt?  Just curious.  What happens if they're not used?

Edited June 6, 2021 by Zed Head

[SteveJ]

The problem with doing it in the engine bay is that the 260Z has a connector that does not match the 280Z distributor connections that you are thinking of.

I didn't trace out all of the circuit paths for the B/Y vs B/W wires, so I included diodes to prevent backfeeding out of a sense of caution. However, from a more detailed look at the EE and EC section, I have determined that the B/Y wire would not be needed for the HEI conversion. Therefore the diodes aren't necessary. 

Here is the revised diagram.

[Shawninvancouver]

oh man,... is there a way for me to just test my unit when its out of the car? if i open it up?

or is there an after market unit that will plug right in??

if i have the coil wired up correct and still no spark does it just make sense to get a new electronic ignition unit?

[Shawninvancouver]

is there a way for me to test this thing>>>????

is there a cheap after market one that will just plug in.. ya know.. plug and play 🙂

[Zed Head]

There is no easy way to test the ignition module.  SteveJ's diagram can be used to install a $25 GM HEI module.  That's about as cheap and easy as you'll get.  

One of your main problems in your posts though is that you describe one issue then don't follow-up to show that you corrected it, then you come back with a completely separate problem.  You started with plug wires that are obviously wrong by your picture.  Then you started looking at your ignition module,  Then you said that you had power to the ballast resistor but no power out of it.  Maybe you meant no spark when you said no power.

There are many small things that you can do to confirm that other parts are correct.  Measure resistance through the distributor pickup coil.  Confirm voltage at the coil itself with the key on.  Measure resistance through the coil.

You can even create a spark by disconnecting and connecting the positive wire to the coil with the key on to confirm that the coil itself will produce a spark and is wired correctly.

You can take your meter and confirm that the ignition module is getting power.  Confirm that it is properly grounded.  Confirm that it is connected to the pickup coils in the distributor,

There's a bunch that you can do and should do if you want to save money and have the best chance of getting it to work.  Plug n Play is only really possible for things that are already working properly.

Edited June 6, 2021 by Zed Head

[SteveJ]

The old testing units are LONG gone from Nissan. Testing with the coil wire near the shock tower is one way. If you aren't ready to fix the issue with the ballast resistor, you can look for resistance to ground at the negative terminal of the coil. Holding the key in start, you should see the resistance fluctuate as the TIU closes the circuit to ground.

As for plug and play? Nope. However, I did lay out most of what you would need to do to create an affordable alternative.

[Shawninvancouver]

Thanks zed..  will try to explain this to you as good as i can,  describing this in print is hard. for reference.. when i say power i mean turn the key only to the power position, when i say ignition / start the car i mean turn the key to the ignition position.

 

when key is on power position - power goes to black white...  that wire goes to one end of ballast. other end of ballast comes out and goes to pos on coil. neg on coil is blue wire.

now  -  i have tried to test for power / spark  coming out of the coil by unplugging coil wire from top of distributor - holding it close to a ground, and turning key to ignition position,, no spark.  i did see a small spark when key was being released from ignition position.  

but no sparking like a spark plug..

ballast got warm ...

coil is a MSD 8203 - is there a problem with coil model??

 

[Zed Head]

10 minutes ago, Shawninvancouver said:

holding it close to a ground, and turning key to ignition position,, no spark. 

i did see a small spark when key was being released from ignition position.  

That's not how a person tests for spark.  The fact that you saw a small spark when you turned the key off suggests that the coil and wiring are correct.

It looks like you don't have a meter or a test light and are just poking around, taking things apart and putting them back together.  Sometimes that works but not often.

Go back through the suggestions and write down what you did for each one.  Where is the rotor under the distributor cap?  Without that you'll never get a spark out to the plugs.  Show that the plug wires are in the correct positions.  Show that the rotor is pointing to #1 when the damper pulley mark is at zero.

At this point it's not even clear that you have ever had a rotor in the distributor.

https://www.rockauto.com/en/catalog/nissan,1974,260z,2.6l+l6,1209181,ignition,distributor+rotor,7136