Testing Pertronix Ignition Module

[z3beemer]

When I did the restoration on my 73 240Z I purchased a Pertronix ignition to replace the points system.  I had problems with it at the time, so I decided to go back to the points system temporarily until I got everything lined out.  Got the car up and running late last year and everything seem fine.  After setting all winter with only occasional starts, I started having starting problems. To make a long story short (after much frustration) I decided to try to go back and install the Pertronix system.  I wanted to be sure it was functioning properly before injecting another problem into my already frustrating situation.  So, I called Pertronix to see if there was any way to check the module out before installing it or buying a new one.  The tech guy at Pertronix was most helpful and walked me thru a test procedure.  I thought I'd pass it on.

The test can be accomplished with the module on or off the car.  I found it easier to do it on the bench using a 12V motorcycle battery I keep around for testing purposes.  You will need a long piece of 14 or 16 ga wire with an allegator clip on each end, a 12V source, and a digital volt meter.

Take the wire w/ allegator clips, attach one end to the module mounting bracket; connect the other end to the negative battery post.

Set the meter to volts DC. Connect the black meter lead to black wire coming from the Pertronix ignition module

Connect the red meter lead, and the red module wire then to the positive battery terminal.  Your meter should read 12V.  If it does not, recheck your wiring, if it's correct and you're still not reading 12V, Module is bad.

If you have 12V, continue the test by passing the magnetic ring pass the ignition module. (use the same orientation of the ring to the module as if it were in the distributor). 

Watch the meter, each time the magnetic ring passes by the module, the voltage should drop to around one volt or so .  If it does, the module is good; if it stays at 12v when passing by, the module is shot.  Mine was. I ran this test again when I got the new module and verified the procedure. It worked as described.

CAUTION!! DO NOT LEAVE THIS CONNECTED FOR A LONG PERIOD OF TIME OR YOU WILL BURN UP THE MODULE

On a related note; you may have seen post cautioning you that if you leave the ignition on without the engine running you will burn up the Pertronix module.  This is true and I think this may have happened with my first module. I asked the tech about this and he confirmed it was true.  I asked how long it would take to burn up.  He said about 2 MINUTES!  This does not apply if the car ignition is in the Accessory position.

[Patcon]

2 minutes!! That's not very long!

[SteveJ]

9 minutes ago, Patcon said:

2 minutes!! That's not very long!

It would explain why they fail.

[zKars]

I heard the rumor once that the “old” or initial Pertronix are prone to the burn out if left on issue, but the later models don’t have that problem. Pertronix I vs II. Searching I see lots of references to I vs II comparisons, but not Datsun 1761 related.  

Pertronix web site does however list a “II” for 240z. PN 91761.   1761 is the old version one. 

So I suggest we get the 9 version from now on. $185 vs $135 of course

There is also the L4 equivalent, 91761 vs 1741. 

They also list replacement modules for both in case it does blow up so you don’t have to buy a whole new kit. 

 

Edited May 5 by zKars

[grannyknot]

I have burned out 2 of the P1's, now I add bullet connectors on the positive side so I can do electrical trouble shooting without risking damage.

 

[Captain Obvious]

On 5/5/2024 at 2:47 PM, z3beemer said:

CAUTION!! DO NOT LEAVE THIS CONNECTED FOR A LONG PERIOD OF TIME OR YOU WILL BURN UP THE MODULE

On a related note; you may have seen post cautioning you that if you leave the ignition on without the engine running you will burn up the Pertronix module.  This is true and I think this may have happened with my first module. I asked the tech about this and he confirmed it was true.  I asked how long it would take to burn up.  He said about 2 MINUTES!

Seriously?? The technology to prevent that has been incorporated into modules for decades. Even the 74 260Z with the stock module has provisions to prevent that. Sheesh.

Trying to save $0.10 worth of components??