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Stumped on HEI wiring
https://www.slantsix.org/forum/viewtopic.php?t=56061		 Page 1 of 1
Author:  dartresurector67 [ Mon Aug 25, 2014 7:08 pm ]
Post subject:  Stumped on HEI wiring
Hi all! I've been collecting parts for an electronic ignition for a year now and I finally had time to tear into it this weekend.

I eventually got everything hooked up right (using diagram below) and got it to start, so while it was warming up I went to grab my timing light. When I came back, I shut it off, hooked up the light (the instructions said to never hook it up while running ), and went back to start it, but nothing happened.

What's weird is the altimeter needle in the dash goes way past dead whenever I turn the key to run, and doesn't change at all when I move the key into the start position. I also am smelling hot (possibly melting) plastic whenever I leave the key in the run position.

My only guess is that there is something wrong with the ignition switch... Any ideas?

Image
Author:  xjarhead [ Tue Aug 26, 2014 4:55 am ]
Post subject: 
Do you have proper fuse's?
http://1drv.ms/1wwcoud

Dave
Author:  dartresurector67 [ Tue Aug 26, 2014 2:44 pm ]
Post subject: 
Nope, no fuses... I must have overlooked that step :(
Author:  Jerame_c [ Tue Aug 26, 2014 8:53 pm ]
Post subject: 
Id carefully check your wiring for melt through or cut through causing you to short out. You had it running but then it quit so I would try to think of anything else that could have changed from running (vibration, heat, etc.)
Given the way the relay is set up in that graphic a bad ignition doesn't seem like it should cause problems. Did you have a heatsink for your HEI module? they need more cooling than the big mopar ignition bricks. Lastly see if your coil is overheating. a mismatch in coil / ballast resistor vs your ignition module could cook your coil.
Author:  wjajr [ Wed Aug 27, 2014 5:51 am ]
Post subject: 
Quote:
What's weird is the altimeter needle in the dash goes way past dead whenever I turn the key to run, and doesn't change at all when I move the key into the start position.
As you know there are two current paths to coil in stock configuration, one when key is in start position bypassing the ballast resistor, and second in run position where 12 v is stepped down via ballast resistor by around 2/3's which I assume you have now bypassed with a jumper or such with this installation.


Somewhere you have a short, it's probably not a dead short where conductor is in clean contact with ground which would cause a quick melt-down of harness, but some sort of connection to ground via some resistance which causes heat build up hence smell of hot wire. Electrical system sees a short via resistance as just another load not unlike a bulb or heating element for an electric choke, and slowly heats up conductor that is feeding that path to ground.

With a relay operated ignition, you need to examine each of the "parallel conductors" or current paths from ignition switch to coil. If you disturbed the bulkhead connector during this conversion, this would be a good place to start looking as these connections are prone to corrosion, heat damage, and will melt.
Author:  dartresurector67 [ Wed Aug 27, 2014 12:18 pm ]
Post subject: 
Thank you for the advice! I'm going back to the shop now and I'll let you know if I make any progress.
Author:  dartresurector67 [ Mon Sep 01, 2014 11:24 am ]
Post subject: 
What a long labor day weekend! I ended up finding the short and now it starts up and idles fine, but any time the rpms get up to around 1300 it misses like crazy, and then it seems to go away at higher rpms. I've tried different settings on the air/fuel mixture and it didn't get any better. I pulled the plugs and they are black from carbon but no oil. To me it seems like a fuel related problem, but everything was working fine before I did the switch. Any suggestions?
Author:  Jerame_c [ Thu Sep 04, 2014 9:56 pm ]
Post subject: 
First try disconnecting your vacuum advance. Then use your timing light while you have someone rev the motor slowly so you can watch what your ignition signal is doing around 1300 rpm. if it is going nuts with no vacuum advance then it is an ignition issue. if the ignition is firing steady and not jumping around then it is likely fuel. Lastly you could be getting too much advance too early so if nothing seems to work you could try backing off the distributor a bit and see if it goes away then.
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