Gremlins in my Fairlady's Ignition System

[Zed Head]

Glad that you can take some constructive criticism.

Look at picture #4 in Post #1. You can see the negative sign above the positive cable and the positive sign above the negative cable. Steve was right. I'm guessing that picture was taken after the sparks flew?

It's not uncommon. My car has some burned wires in the harness, probably from the backwards connection. I'm not sure what damage occurs when this happens but there are many cars out there that have recovered. It will take some time with the meter to figure out what's right and what needs fixing.

[dasmoover]

Photos were taken the day of the post weeks after the incident. I think the first line of business it to get the voltage readings in different states and then isolate that extra blue wire. From there if that doesn't solve it, I'm going to have to get to know my meter quite well.

[dasmoover]

I've confirmed my wiring is correct as far as the ballast resistor, coil, and transistor ignition unit go. I'm going to buy the HEI module and wire that in. I imagine since the battery is directly connected to the TIU it may have caught that spark and may have been rendered damage. Here are photos detailing the mystery wire, ballast and coil. Any inspiration beside TIU? Maybe fusible links by battery? Thanks.

I am getting 8volts with ignition on so it seems circuit carrying the high tension power is not available. Which is the high tension wire so I can fully trace and test? This is why I imagine the TIU is damaged.

[Zed Head]

8 volts implies that you have a short circuit, maybe in the ignition module. I assume that you're measuring from one of the terminals on the ballast or at the coil, to ground. 8 volts would happen if current was flowing. Your coil would probably get hot also.

Disconnect the blue wire that comes from the harness (going to the ignition module, on the ned in your picture with the brass nut showing) and connects to the ballast and see if the 8 turns to 12. If it does, then disconnect the blue wire at the ignition module (inside the cabin) and reconnect the blue wire at the ballast and check again. If you get 12 again, then you can be fairly certain that your ignition module is shorting out.

I think that the mystery blue wire connects to the condenser/capacitor. It's a small silver can-shaped thing that usually bolts to the coil bracket, I think. It's not necessary and having it disconnected takes it out of the picture as a problem source.

[EuroDat]

That mistery blue wire is for the AC compressor clutch. If your car has factory airco it should be connected to a black wire that comes from the compressor just behind the pulley. Its not causing the problem the way it is now.

Its shown in the 77 FSM in section AC37 and AC38.

You should do the checks Zed Head posted. Sounds like it could be a defective ignition module.

Chas

Edited July 6, 2014 by EuroDat

[dasmoover]

Just to be sure, you guys are talking about the little black box next to the distributor? Here's a picture without the cap, looks golden. Or are you guys discussing the TIU like I am talking about up in the passenger kick side?

I only get 8v with ignition on, have not tested while cranking yet. Will do those tests as soon as I can confirm that I'm testing with the TIU. Thanks.

[SteveJ]

You only get 8 V because the circuit goes through the ballast resistor as I said in post #4.

[dasmoover]

You only get 8 V because the circuit goes through the ballast resistor as I said in post #4.

That's what I had initially thought. I am going to replace TIU with HEI module. StevebJ, what other tests can you recommend or items to look at? Thanks.

[SteveJ]

Just to be sure, you guys are talking about the little black box next to the distributor? Here's a picture without the cap, looks golden. Or are you guys discussing the TIU like I am talking about up in the passenger kick side?

I only get 8v with ignition on, have not tested while cranking yet. Will do those tests as soon as I can confirm that I'm testing with the TIU. Thanks.

The TIU is on the passenger side footwell. The picture you posted is part of your AFM.

Please post a picture of your distributor before you go the HEI route. Many owners have swapped in a ZX distributor. That has the ignition module mounted on the distributor. If a previous owner did that to your car, the HEI is superfluous.

[Zed Head]

We're on a do-loop for picture taking.

Actually, the GM HEI module can be made to work with the ZX distributor. Same red and green wires, just contained inside the distributor.

If we pull enough of these teeth, this engine will eventually run.

[EuroDat]

The wiring looks too stock to have a ZX dizzy, but I could be wrong. A photo of the dizzy would certainly clear that up.

Here is a phot of the blue wire in my 77 280Z. It shows the connection to the AC compressor.

I had a lot of problems with my TIU when it was warm and i did a crude HEI Module swap to see if it would help. Here is a photo of it now. I made it completly reversable so I could return it to original if it didn't solve the problem.

I am planning to build the HEI module into the old TIU casing and get it back to stock looking.

Not saying you should now change to the HEI module. There is still some checking you should do before you make that move. I just wanted to give you an idea what it is.

Chas

[SteveJ]

We're on a do-loop for picture taking.

You noticed that, too?

I know the HEI would work with the ZX, but I didn't want to go into all of the permutations given the OP's lack of experience. I would just suggest swapping in a new ignition module at that point.