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HEI upgrade from points need wiring help

3K views 12 replies 6 participants last post by  sargas3 
#1 ·
HI everyone,

I have a 1974 cj-5 4.2 and I am trying to replace the old points with an HEI. The instructions with the distributor seem to be missing how I connect the wires. I have no tach but im not sure if I remove the coil what I do with those wires and what wire needs to go into the distributor dongle. In the pictures you can see what I'm talking about. The wire with the blue connector is plugged into the coil positive spliced to what I think is the ignition module, and runs to the blue connector on the starter solenoid. Also there is the green wire connected to the coil negative. Not sure where it goes. Ive been looking for the answer for a few days. I could really use the help.
 

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#2 ·
Very simple:
Remove the ballast resistor.
Take the ignition wire that was connected to the ballast (bottom wire in pict 2) and hook it up to the green wire coming off the dist.
The wire that was connected to the - side of the coil goes to the points (old dist). It can be removed.
The bypass wire running from the solenoid to the coil is no longer needed and can be removed as well.
You can remove the old coil and bracket as well.


HEI's like a lot of voltage. Most folks run a heavier gauge wire from the battery through a relay to power the dist.
 
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#3 ·
Very simple:
Remove the ballast resistor.
Take the ignition wire that was connected to the ballast (bottom wire in pict 2) and hook it up to the green wire coming off the dist.
The wire that was connected to the - side of the coil goes to the points (old dist). It can be removed.
The bypass wire running from the solenoid to the coil is no longer needed and can be removed as well.
You can remove the old coil and bracket as well.

HEI's like a lot of voltage. Most folks run a heavier gauge wire from the battery through a relay to power the dist.
Thank you, If the weather holds up ill get to work on it this afternoon and let you know how it goes. Really appreciate the help!
 
#4 ·
So good news bad news. So I followed the instructions and I was able to start the jeep. It was running but timing was off and I could not read the line with the light so I went to turn it off to mark the line better but it would not turn off. I panicked a little pulled the battery but it stayed on. Then I remembered If I plug the carb it will stop. Anyway im not sure why I did wrong between the ignition switch and the distributor wiring. I'm not quite sure where to look but I am guessing its in the ignition switch. in the last picture the loose red wire with the blue end was disconnected last week so I figured it just fell out while I was working under the dash. I put it on the ING where it looked like it came from. So when the Jeep would not turn off I figured that wire should not be there. Well without it the Jeep doesn't turn over so I guess that's not it. However when I it touches the ING I hear a click from the thing in pic 3 and 4 with no key in it.

The top red wire was also loose with no end on it. I had thought I pulled it out of the end connector with the other red wire when I went to fix the first wire. now im not sure it was connected.

Jeepdaddy2000 had said "HEI's like a lot of voltage. Most folks run a heavier gauge wire from the battery through a relay to power the dist." Can you tell ne what kind of relay id need and does it go from the dist right to the battery?

Thanks for all the help! I love this site!

p.s. the box on the drivers side fender in pic 2 was warm when I got started. not sure what it is but I think my connecting the wrong wires may have had something to do with it.
 

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#5 ·
The thing you are pointing at it in your last photo is the ignition switch.

Your wires may not be following standard Jeep colour coding methinks so start with verifying.

Get a voltmeter or test bulb and verify what you are getting at each terminal and see if those same colour wires run out to the distributor and starter solenoid.

You should have a BATT feed, a permanently live feed. This would be large and Red. Find out which ones in STOP or OFF are live. They will connect to one side of the starter solenoid to the really big wire from the battery. that floating red wire you have your finger on may be the main feed from the battery.

There is an IGN terminal. These should be red with tracer. Only live in RUN and START. They should connect to your HEI distributor and other things. make sure that when they are live, the HEI is live and at no other time.

there is an ACC terminal. These are yellow. They are non essential stuff such as the voltmeter which does not operate in Start.

There is a START terminal. This should be light blue. Live only in Start. It is connected to the starter solenoid, it becomes a light green wire. When the solenoid is energised it then connects to the coil via the I terminal on the solenoid. This I tab connection is no longer needed and the ballast resistor or resistor wire should have been cut out. Disconnect it from HEI circuit, take that wire out from the i tab of the solenoid.

The white block on the coil is a ballast resistor. It reduces voltage from 12 Volts to 7 Volts so in normal running this is all the coil uses. to get a stronger spark in Start for a few seconds you have the wire from the I tab on the solenoid feeding 12 Volts. When you changed to HEI you did away with the need for it, the HEI runs on 12 Volts all the time.


Now back to the engine bay.

Ignore a lot of the stuff you have, it is now a 1974 with HEI. The large silver box is not relevant to your HEI.

The light green wire from the HEI is spliced (open that insulation up, make sure it is soldered or connected properly) to a black wire that goes to the ballast resistor and is spliced with the wire from the I tab on the solenoid at the coil +ve. Cut all this crap out and connect it solely to a good supply from the IGN which should be red with a white tracer.
 
#7 ·
Doesn't the HEI install sometime needs a diode to the alternator to prevent it from running on?
x2 what John said with the "engine run-on". After I installed my HEI, it would keep running with the key off. If you have a manual transmission, you can always just pop the clutch and kill the engine. Anyhow - a diode fixed the problem.

To power my HEI, I installed a relay with a fusible link from the battery like others mention above - it's really easy and ensures you have the full voltage. The diagrams below should help. I'm not sure who to credit for them - but they are what someone sent me and they should answer all your questions. Good luck, report back.
 

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#12 ·
Why did you decide to go with the HEI conversion? Recently our 74 decided that the points wouldn't stay in adjustment and I converted the distributer with a solid state Pertronix system. In less than 30 minutes after delivery I was driving it. Cost was very affordable. I could have got cheaper but it would have taken longer than the two days Summit took to have it in my hands. Works with the stock coil too.

https://www.summitracing.com/parts/pnx-1162a/make/jeep/model/cj5/year/1974
 
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