Is it me or does the E12-80 module need to be replaced?

[yoshi_w]

Hi, so I just finished rebuilding the engine on my 1973 240z and it turns over, but no start. Its getting air and fuel so it seems logical the only reason its not starting is the spark. My car has an MSD blaster 2 coil and an e12-80 module. We used the multimeter and determined that both the positive and negative side on the coil are getting around 12v, is this right?? Same thing goes for the b and c on the module. I am assuming the negative is supposed to be grounded, so am I missing a connection on the wiring harness? Or is the module messed up? Thanks for the help! I have it hooked up like this diagram:

Edited April 13, 2013 by yoshi_w

[Zed Head]

Your voltage measurements are right. The making and breaking of the primary circuit, to make the spark, only happens when the distributor is turning and the pickup coil is producing voltage changes (positive and negative current). The module breaks the ground circuit to protect the coil and module itself if the distributor's not turning.

Ignition modules are hard to diagnose with just a meter. Your best bet is to pull a spark plug wire and stick a spark plug in. Ground the plug threads, spin the engine and watch for spark across the gap.

The reluctor magnets on the ZX distributors are quite often broken, from the ones I've seen. If you have a used one and have never run it.

[SteveJ]

Hi, so I just finished rebuilding the engine on my 1973 240z and it turns over, but no start. Its getting air and fuel so it seems logical the only reason its not starting is the spark.

Not necessarily. It is also logical that the timing is off. An inductive timing gun could tell if whether or not you have a spark and if the timing is correct. Are you sure you had the engine at TDC on the compression stroke when you inserted the oil pump?

My car has an MSD blaster 2 coil and an e12-80 module. We used the multimeter and determined that both the positive and negative side on the coil are getting around 12v, is this right?? Same thing goes for the b and c on the module. I am assuming the negative is supposed to be grounded, so am I missing a connection on the wiring harness? Or is the module messed up? Thanks for the help! I have it hooked up like this diagram:

[ATTACH=CONFIG]62582[/ATTACH]

Now, when you measured either side of the coil to ground, you got 12 VDC. That sounds correct. You were doing your measurements with an inductor in the circuit.

[yoshi_w]

We timed the oil pump and everything, we made sure the pistons were at tdc when we installed it, and we tried a screwdriver and turned the engine over but the spark was a little weak, we also tried turning the distributor for rough timing and nothing changed, if the coil isn't properly grounded could that be the issue?

Edited April 14, 2013 by yoshi_w

[SteveJ]

One way to test the coil:

1. Disconnect the wires from the coil.

2. Measure resistance from the positive to negative terminals. (primary)

3. Measure resistance from the center post to negative. (secondary)

The resistance of the secondary side of the coil should be several thousand times more than the primary side. If it's significantly less, the secondary side of the coil is bad.

The primary side should probably be about 1.5 ohms or so. If it's less than an ohm, the primary is bad.

Also, post clear pictures of the rotor and the inside of the cap. If they are worn/bad, you won't have a good spark.

Finally, you can download the 1980 FSM and read pages EL-24 to EL-26.

[Pop's Z]

Also, be sure to connect the wires together that were on the ballast resistor. If you don't the car will not start. I assume you removed the ballast resistor when you added the new distributor.

Cheers, Mike

[yoshi_w]

Steve, I am about to go work on the z so I will definitely try that test, and Mike, that could be the issue because I cannot remember if we remembered to do that, do you by chance have a picture or way to reference which two wires go together? Sorry, my wiring is a mess.

[SteveJ]

Good point, Mike. If the black/white and green/white wires aren't both on the positive after deleting the ballast, the car will start, but it won't run. Oh, and since the tach was changed to a later year tach, you also have to bypass the tach on the positive side. It looks as though the OP did that.

[yoshi_w]

Alright, I'll see if I can locate those wires and go from there, thank you for all the help and if anything I'll post up results of all this.