Gremlins in my Fairlady's Ignition System

[Zed Head]

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?

For future reference, that is your TPS (throttle position switch).

There is one other very simple possible fix, maybe short-term, for your ignition module. In your case (no offense) it might be a quick easy way to test. Your 1977 car probably has two ignition circuits in the module, like my 76 did. It may be that one is damaged, but the other is okay. You could disconnect one,leaving the other in control.

But you really need to confirm that the problem is in the module first. You could easily damage the HEI module when installing it (they're sensitive to wiring) and you wouldn't know any more afterward than you do know. The meter will tell you what you really need to know before you make any changes.

[dasmoover]

I can confirm it is the stock distributor. The car ran before the live spark damage. I'm set on the idea that the TIU was damaged when the sparks flew. This could explain why I do not hear the door buzzer when I turn the ignition on.

The fuse is fine, hazards work. Turn signals do not light up on the dash.

[Zed Head]

I'm set on the idea that the TIU was damaged when the sparks flew. This could explain why I do not hear the door buzzer when I turn the ignition on.

Not quite. You probably have other problems besides the ignition module.

Meter, meter, meter, meter. You have the meter and you'll have to crawl up by the fuse box anyway. You can actually take the voltage measurements at the ignition module before you disconnect it. Which you will have to do anyway if you install an HEI module. If you disconnect the blue wire at the ignition module and still measure 8 volts when the battery has 12+, then your problem is elsewhere.

Turn key On, measure voltage on blue wire at module to ground, turn key Off, do same.

[Captain Obvious]

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

Chas, Did you do that, or are you thinking of doing that? Did you take those pics?

[EuroDat]

Chas, Did you do that, or are you thinking of doing that? Did you take those pics?

Im in the proces of doing it. The TIU is finished, but haven't had the time to build it back in.

Ill start a new thread about it when I get back at it.The car is driving ok now with the module behind the coil so the pressureis off to get it finished.

Chas

[Captain Obvious]

Im in the proces of doing it. The TIU is finished, but haven't had the time to build it back in.

Well you got it bad, my friend. You know... That car guy thing that makes some of them do weird stuff? You got it bad.

Not saying I'm any different. I'm just sad that I didn't think of that TIU mod first. :laugh:

[SteveJ]

The TIU case would provide a nice heat sink for the HEI.

[dasmoover]

I did a test with the multi-meter. I get 12v with ignition off. With ignition on I get absolutely no voltage on the blue wire. I'm holding off on the HEI module until I figure out why I lose voltage.

Any thoughts? I've overlooked all wires that are exposed outside of the main harness. No loose connections/grounds there. I'm worried it may be somewhere inside the harness.

Perhaps fusible link on battery terminals?

[Zed Head]

It's not clear where you're measuring. Blue wire at the module, at the coil, at the ballast, or the mystery blue wire?

Does anything else that should have power not have it when the key is On? Like the positive post of the coil?

[dasmoover]

At the ignition module passenger side as Steve suggested.

[Zed Head]

Is that with the wire connected or disconnected? Sorry, but these things make a difference. What you might be seeing is voltage from a pullup resistor in the module, that goes away when the other side of the transistor gets power (full disclosure - I don't really know about this). Transistors and the way they're used is not typical electrical stuff.

I'm just trying to get you to something that makes sense. It shouldn't be that hard. If you're tired of my comments, I can bow out.

I asked about the positive terminal on the coil because it should be connected to the blue wire you measured, through the coil. Module-blue wire-ballast-short blue wire-coil negative-coil windings-coil positive. If you don't see the same thing at the positive terminal it will give you a clue about where the break in the circuit is.

Edited July 10, 2014 by Zed Head

[dasmoover]

To clarify I am testing the transistor ignition unit at the passenger panel as suggested by Steve. My wiring is 100% correct as far as ignition system goes. The ballast and coil are wired properly.

I disconnected the blue wire from the Transistor Ignition Unit and tested for voltage with key off and on. At off I get 12v to it from the battery as suggested is correct. With the ignition on, wire still disconnected from TIU I get no power.

I believe this wire is shorted somewhere.

I AM NOT TALKING ABOUT MEASUREMENTS UNDER THE HOOD.

I am doing these measurements at the blue wire at the TIU.

I repeat, my wiring setup is OEM Stock and have confirmed it is correct tracing the wires.

This is NOT at the ballast, coil, etc. UNDER THE PASSENGER KICK PANEL with the TIU.

No disrespect, I appreciate all input, thank you Zed Head.

I just want to provide the correct information to expedite the car's revival!

Edited July 10, 2014 by dasmoover