Pertronix Installed No Spark

[Groosh]

Hi. I recently installed Pertronix on my Marelli distributor. The car ran before hand, this was the only change.

Both the positive and negative were hooked directly to the coil as instructed. The wire that used to power the points was taped off. However, I'm not getting any spark.

I tested my coil and have 3.5 ohms. I tried hooking to the red Pertronix wire to the lead for the points. Still the car doesn't fire. No spark through a timing light on cylinder #1.

I did have to pull the distributor to install the Pertronix. But I've pulled it before and am pretty certain I installed it back as before.

Any thoughts are appreciated. Thanks, Paul

[ossiblue]

Two things to check. First, if you, at any time, connected the wires incorrectly, it's possible that the unit is damaged. Second, you need to have the correct air gap between the magnet on the distributor shaft and the sending unit.

Try reinstalling you points and see if you get spark/firing. If no spark something is amiss with the wiring from the CDI/coil to the points or your distributor is way out. If there is a spark, reinstall the Petronix carefully and let us know what happens.

[47silver]

Post a diagram of how you wired it

[Groosh]

Thanks for the replies. When I test voltage at the coil with the key switched on, I read no volts. I'm not sure what changed. The car was running on points just the other day.

There are 12 volts at the wire previously connected to the distributor points. Those wires are not connected to anything. I feel like they should go to the positive of the coil. They are black with purple stripes. The wires currently on the positive of the dizzy are blue with yellow and blue with white.

[Groosh]

The wires on the bottom with black tape around them (black with purple and black) were on the distributor plugged into the points when the car was running.

[47silver]

Power goes to pertronix red
Pertronix black goes to the cdi
Look at pertronux site

[Jonny H]

If this is a non CDI car then the connections should be ok (12v on coil primary)


If this is a CDI car:

1) you have probably destroyed the Pertronix unit as the coil has 300V on the blue/yellow wire.
2) you have the wrong coil. Just an observation.

[mb911]

I recently had the same problem . went to there website and found proper instructions for wiring with a cdi and how to properly test the unit. I even talked to pertronix and they were a huge help.

You have it wired wrong..

[Groosh]

Darn. So I read the Pertronix instructions and they said I needed 3.0 ohms in the coil. The coil I had was only showing .3 ohms so I swapped it out because I wasn't getting any spark. I thought maybe the coil was bad.

This is a stock 1971 2.2T, so the original CDI is in place.

[Jonny H]

Originally Posted by Groosh

Darn. So I read the Pertronix instructions and they said I needed 3.0 ohms in the coil. The coil I had was only showing .3 ohms so I swapped it out because I wasn't getting any spark. I thought maybe the coil was bad.

This is a stock 1971 2.2T, so the original CDI is in place.

Just to be clear, the coil change won't have damaged the Pertronix but the way you've wired it might have done. It depends whether the CDI unit actually fired as to whether it is toast or not.

Connect the Pertronix red wire to a 12V feed (e.g. one of the terminals the 3 way fuse panel). Do not connect it to the coil.

[dicklague]

Think of it this way. The Pertronix are electronic points.

They have electronic components them and they need 12volts DC to run. So the red wire is how this voltage gets into the electronics. The black wire is the signal to the coil or the CDI that the old points would have produced.

So everything is the same.....BUT YOU HAVE TO PROVIDE 12 VOLTS TO THE RED WIRE.

You want this to be switched 12 volts, so it only energizes the Pertronix when the key is on.

I have had Pertonix in my 1973 911 for 15 or more years and it has worked flawlessly. It is a very good system.

[Quickstep192]

Here's a link to the wiring diagram for a CDI. I don't know why they don't include this n the uvstructuons that come with the kit. Would sure make life a lot easier for us CDI folks.

http://www.pertronix.com/support/tips/pdf/porsche_cd_diagram.pdf

[Groosh]

Thanks guys. I'll have a look later in the week. Does anyone know how to test the Pertronix unit to see if it will still work? I'm kinda assuming it's toast though...

[dicklague]

Originally Posted by Groosh

Thanks guys. I'll have a look later in the week. Does anyone know how to test the Pertronix unit to see if it will still work? I'm kinda assuming it's toast though...

I think you would need an oscilloscope to test it. Feed 12volts to the red wire on the pertronix and attach the scope to the black and watch for a square wave pattern when you turn the distributor.

[Quickstep192]

Originally Posted by Groosh

Thanks guys. I'll have a look later in the week. Does anyone know how to test the Pertronix unit to see if it will still work? I'm kinda assuming it's toast though...

I wouldn't assume it's toast. Before I found the proper wiring diagram, I wired mine a zillion different ways and didn't toast it. I did toast my tach though.

If it's still installed, I'd think the easiest way to test it is to wire up it up properly and see if it works.

[Groosh]

I followed the diagram above (thank you Quickstep192) and confirmed with Pertronix my previous foibles of connectivity did not burn out the unit. The car is up and running!