Ok guys having trouble wiring this Unilite into a 75 280Z...help please

[RPM Resto & Custom]

So I've been trying to wire this new Mallory Unilite into my customers 75 280Z and I'm a bit confused as I'm finding conflicting information. Along with the Mallory I'm also upgrading to the Crane PS20 coil. Motorsport Auto says to retain the factory ballast with this coil. I did some quick checking and it doesn't appear that any of the posts on the factory ballast get less than 12V with the key in the on position. Am I wrong on this?

Also I've read that you must run a ballast that drops the voltage down to the 6-8V range to keep from frying the module on the Mallory...so how do I make this work with a stock ballast that doesn't seem to be cutting the voltage? My new coil came with a ballast that I wired in for now but with the key in the on position it start to SMOKE!

Right now I have the distributor wired as such....12V ignition and red dizzy wire to one side of ballast. Other side of ballast to Coil +. Green dizzy wire to Coil -. Brown dizzy wire to engine ground. The timing should be close enough to start however I don't think I'm getting an injector pulse....which I think is due to the stock blue wire being removed from the Coil-. However when I do hook this wire up I lose my spark.

What am I doing wrong here?

[SteveJ]

When the key is in the Start position, the ignition circuit bypasses the ballast resistor. Keep in mind that there probably is some voltage drop by virtue of the draw of the starter motor. Even if it is above the 6 to 8 volt range, you shouldn't have this circuit live for long.

The stock ballast resistor does drop the voltage to about 9V.

As for the smoke issue, you aren't very clear. What was smoking? No offense, but my guess is that the smoking component is something you wired. You probably grounded out something, and your fusible link just didn't blow (or has been replaced by wire).

[RPM Resto & Custom]

Steve,

I installed the ballast that came with the PS20 coil as a standalone ballast for the distributor and that was what was smoking.

Which terminal on the stock ballast should I see the reduced voltage one?

[Zed Head]

The ballast resistor might have connection markings molded in to it. The factory unit does. I don't think that you will see the lower voltage unless current is flowing.

You're probably right about the blue wire and the injector pulse. You might be losing spark because you haven't disconnected the factory ignition module.

Which brings up the general point of why are you installing a new distributor, with its own ignition module (not sure if all Unilites come with their own module but I think that they do), when the 75 came with its own? Did the old module go bad? Did you unplug it?

[RPM Resto & Custom]

I did not unplug the old module. It's in the driver area kickpanel correct? I'm installing the Unilite upon request from my customer. He basically came to me with a list of upgraded parts he wanted to install. The ballast that came with the coil has no markings...and if my electrical theory is correct it's just a resistor and can be installed in either direction. The factory ballast has 4 posts while the new one has only 2.

[Zed Head]

Your customer does not know what he's asking, I think. But, of course, he's right.

If you don't unplug the factory module, the circuit doesn't break and you won't get spark. Just unplug it, it is a branch off of the blue wire. The ECU and the tach need the blue wire to be connected to the coil - terminal. No, the module is in the passenger kick panel area. You should download the FSM and read the Electrical section.

The factory ballast has two resistive circuits, one low for starting and one high for running. If you just have two then you'll need to run the starting circuit and the running circuit both to one side and the output to the coil + from the other end.

The smoke means that the resistor is getting hot because there's a short on the coil side, which might mean that the module wire is not corrected properly. The module is the "breaker" part of the spark circuit. Sounds like your circuit is always "made".

[RPM Resto & Custom]

You're correct he probably doesn't....although ignition upgrades to Z cars isn't my specialty either. I talked to him on the phone and we may ditch the Unilite but I do also have an XR3000 here that he is interested in installing instead because of the optical trigger system. Still don't think the fancy doo-dads are needed for his setup but to each their own. I know the 3000 requires disabling the factory module as well which I've done. It does call for you to bypass the factory ballast however which I'm still a bit unclear on how to do.

[Zed Head]

You might explain to him that he already has electronic ignition. Maybe he thinks that he has a 240Z, which came with points.

The "lite" in Unilite mean optical I believe. Unilite - optical, Crane XR3000 - optical, Nissan 1975 280Z, variable reluctor. All three are electronic.

They'll all do the job, but not together. You'll still have to disconnect the factory unit, since it will still be running current through the coil if you don't.

[RPM Resto & Custom]

Got it all squared away. The Unilite is going to the side for another customer's 240 project I'm currently working on.

I disabled the factory module and installed the XR3000 with no ballast jumper as I believe that disables stock tach function. Everything seems to be working properly at this point. Tomorrow I need to install one of those add on fuel pressure regulators which should be another adventure. This car may benefit from it however since it's got a stroker kit, a larger cam and some head work.