Installing HEI Distributor / need help

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j5ball

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I bought a HEI Distributor for my 1968 pontiac lemans 350. This has the ignition coil on top of the distributor. There were two wires going to my old ignition coil when I was running points & condenser distributor. What are those two wires? I soldered those two wires together and connected them into the Battery connection of my new HEI Distributor. Now I have a short somewhere . . not sure where. Thoughts and ideas? I was thinking one of the wires came from my ignition switch (key turn switch) and the other wire was a hot wire coming indirectly from the battery or maybe from the starter. Ahhhh. Thanks . . . JIMB
 
Ok. Going through and deciphering diagrams I think I have found the wires that were going to my ignition coil. One wire was for Ignition position 1 (normal operating and running position) and the other wire was for Ignition position 2 (starting position). Can someone confirm this for me?

I really don't see a problem with putting these two wires together and running them to the Battery connection on my MSD distributor. After all they were connected into the old ignition coil as one wire. So, why am I shorting out. I can connect the battery and all the lights work, I can put the key to ignition position 1 and all seems ok, when I put the key to position 2 (start position) I hear the starter kick for a split second then all lights go off and I get nothing. I can disconnect the battery then reconnect the battery and all the lights come back on and all seems normal. Until I push the key to Ignition position 2 - and the same thing happens - no lights and all is dead. Very frustrating. Any help? Thanks . . . JIMB
 
Did a little testing this morning. Test 1: No battery hook up then no volts going to new HEI distributor. Test 2: Battery hook up and key inserted into ignition but no ignition turn then no volts going to HEI distributor. Test 3: Battery hook up and key inserted into ignition and key turned to ignition position 1 then 12 volts reaching HEI distributor. So my wiring theory seems to holds true at least for ignition position 1. Still, no understanding of why I am loosing all power when I move key to ignition position 2.
 
You can not use those wires for HEI. There should be a terminal in your fuse box marked IGN, if not find one that is hot both with the key in the RUN position and the CRANK position and run a wire from that terminal to your HEI.
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Melsg5 . . Thanks for the info. Not questioning your advice. Just looking for a reason so I can better understand why what is happening is happening. Thanks . . . JIMB
 
The two wires that connect to the positive side of a points style ignition coil consist of one wire that only has power while cranking and supplies full battery voltage and typically is connected to the starter solenoid. The second wire is a resistance wire and only supplies power once the engine is started and is typcially connected to the ignition switch. Hope that helps.
 
Ok. You are getting me there. So why does this short my entire car out when I try to start it. Logic tells me that when I turn the key to ignition position 1 (before the car has started) there are 12 volts pushed to the MSD then when the key is pushed to ignition position 2 (to start the car) there are 12 volts pushed to the MSD then when the key returns from ignition position 2 to ignition position 1 (after the car has started) there is still 12 volts pushed to the MSD. So at any given time the MSD is getting only 12 volts. What am I missing? Thanks . . . JIMB
 
I think these r some of my options to tie into to supply the MSD the consistent 12 volts it needs once the key is in the ignition. Which line is the best: Radio. Oil sensor gauge line. Brake sensor gauge line. Engine temperature guage line. Or something else? Thanks. JIMB
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Find an unused circut to hook it too. If all else fails, hook it to the battery. I think MSD recomends this.
 
Lets say I hook the MSD directly to the battery because its the easy way out. How does the car turn off when I turn the key off? Tx. Jimb
 
Use a voltmeter to determine which fuse is hot both in the run and crank position of the ignition switch.
 
Don't have a drawing in front of me. Don't remember how it was switched off and on. The car will stop when the signal from the distributor stops.
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Mystery solved. Finally back home tonight to spend some time with the car.
Invited my neighbor over to help me.

Through all the work I have been doing on the car (rebuild carb, removing of fenders, removing of inner fender wells, raising engine, replacing manifolds with headers, replacing motor and frame mounts, replacing starter, replacing plugs, replacing plug wires and I am sure I am missing something) the negative cable on the battery post came loose enough that when the engine was trying to start it created a short. The negative connection was tight enough though that when I pushed the key to Accessories or Ignition 1 all was good. But the connection on the negative side was not tight enough when pushing to Ignition 2 and starting the engine - thats when the short occurred. When I tried to start the engine my neighbor noticed a small puff of smoke come from the battery. Sitting in the car I would have never seen this. This is when all lights went out. Then he wiggled the negative cable and all lights came back on. Whew, that was easy.

Back to the new MSD. I used the two wires that were attached to the old ignition coil. One wires supplies 12 volts when in position ignition 1. One wires supplies 12 volts when in position ignition 2. You need both wires so at any time the MSD is only getting 12 volts. If you hook the MSD up directly to the battery the car will start but when you pull the key out attempting to shut down the engine the engine continues to run. Because the MSD is still getting the juice it needs by being connected to the battery. The MSD does not know to shut down.

Let me know if there are any questions.

Thanks . . . JIMB
 
Are you still running the old ignition wires? like Mel said, the wire for position 2 is a resistance wire. It wont carry the full 12 volts. Points ignitions cant handle 12 volts. The resistance wire knocked it down to 8 or 9 volts. This will effect your MSD ignition performance.
 
Yes, I am still running the original ignition wires. Ignition 1 position wire does supply 12 volts (tested and verified.) Ignition 2 position wire only supplies 9 volts (tested and verified.) And when Ignition 2 position wire is carrying 9 volts Ignition position 1 wire is carrying 0 volts. (tested and verified.) And vice versa (tested and verified.) But Ignition 2 position wire is only for starting. Which seems to be enough to for the new MSD coil. Once the car starts and the key returns to Ignition 1 position the MSD is getting a full 12 volts until the engine is turned off. Do you think only have 9 volts during the starting sequence will damage the MSD? I bought my MSD from the Charlotte Auto fair 2 weeks ago for $45.
 
You have it backwards the MSD is getting the 9 volts with the engine running, assuming nobody miswired something, and you get 12 volts when cranking. This is why you should not be using those wires and find a hot fuse both cranking and running and tap off that.
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Someone must has mis-wired. I tested the individual wires and I get the 9 volts when starting and 12 volts when running. Better to be lucky than good some days.
 
I would check the wiring at the starter solenoid.
 
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