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Discussion Starter #1
Hey guys so i installed a petronix ignition into my '68 p1800s and boy what a difference! Now i just gotta do the carbs and itll feel like a new car! Only issue i am having is the tachometer. Before the petronix, the points ignition system was installed and with it the tachometer worked just fine. There is a tab that sticks out of the distributor where one of the white wires coming from the tachometer would attach to. The other white wire coming from the tach would goto the bosch blue coil. Well the petronix does not have this tab, so i wired it as per the diagram that came with the petronix from ipd and still nothing. I have burned out two petronix;s trying to swap wires around to see what happens and i dont want there to be a third! Any help would be greatly appreciated!
 

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The tach goes in series with the coil trigger signal.

Original wiring: wire from points -> wire to tach -> wire from tach -> coil negative

New wiring: wire from Pertronix -> wire to tach -> wire from tach -> coil negative
 

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Discussion Starter #3
Thanks Phil! I have the hook up a little different i think, and forgive my stupidity with this. The photo below is how i have it hooked up and i dont have any tach yet.

 

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Your diagram is correct, but is it possible you've switched which white wire is which? The car will run either way, but the tach will only work one way. You won't hurt anything if you experiment with switching them.
 

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Thanks for your quick reply phil! I have switched the wires around, except i have gotten a burnt module when i put the red wire from the ignition to the negative side of the bosch coil as per the ipd diagram.


Im at a roadblock =\
 

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Pertronix red wire goes to the coil positive.

Pertronix black wire goes to the white wire that used to connect to the distributor. That connection floats -- it does not touch anything else.

The white wire from the tach that was on the coil negative stays there. Nothing else connects to the coil negative.
 

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Discussion Starter #7
OK, I had it setup that way but for whatever reason i still didnt get any tach. i will try it again tonight if it warms up as its freezing up here in NYC! Thanks again for the help phil and ill update you once i do it!
 

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Did you resolve the tach issue? I am hooking up mine very soon (pertronix installed) and don't wish to burn anything out...
Can you publish a final diagram of what worked please?

Thanks
 

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Discussion Starter #9
Hey Toomany toys, i havent had the chance to yet as its been really bad weather up here in nyc. As soon as i get a chance i will apply the advice that phil gave me.
 

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Discussion Starter #10
UPDATE-Many thank to Phil Singer! I got the tachometer working finally based on his advice! I dont know how the wire hook up wasnt working before, but it is working now and its wonderful! I have included a diagram of the wire set up i did that worked. In my case, the longer white wire that came from the tachometer was the one that went to the distributor and was the one that needed the negative wire from the petronix. the shorter wire was the one that needed to stay on the Bosch coil. the positive stayed on the positive side along with the ignition wire. Thanks again Phil! I coulda saved myself $110 bucks had i checked here first!

[/url]ignitiondiagram by edavidadorno, on Flickr[/IMG]
 
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