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guide to orange box troubleshooting

Billccm

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I volunteered to help a frustrated friend get his 69 Coronet running. Back in the day I had orange box ignition on my B Body cars, but that was over 20 years ago.
Some background
69 440 mostly stock. Ran well and one day just quit. He has confirmed no spark. Everything, and I mean everything is new including the distributor, ballast, multiply orange boxes, coils, etc. He has 4 other B Body cars that run and swapped one by one components and this Coronet does not get spark.
So I have some wiring to trace, but wanted some advice as I dive in next weekend with just a test lamp and my trusty analog meter.
Take care Bill
 
From what I've read and experienced, Orange boxes went to crap in the late '90's/early 2000's. I had an orange box I bought in '89 that was used on multiple different cars over the years and probably had well over 300K on it by the time it started going bad (would randomly cut out and often start right back up on its own if you were driving at the time). I bought another one about '03. Car ran noticeably worse and completely died less than 1000 miles later. I ended up going with a stock parts house one.
With your friends car, first thing I would confirm is that the ECU has a good ground. If its been replaced multiple times, the holes may be wallowed out and not making good ground. On my wagon, I went as far as using a nut and bolt on one side (had access to the back), and running a braided ground strap from this to the engine block.
Aside from that, I would be looking at wiring connections at the ignition switch and firewall.

Good luck!
 
Chrysler Electronic Ignition Wire Diagram 4 pin Ballast & Electronic Volt. Regulator.jpg

Chrysler Electronic Ignition Wire Diagram 2 Pin Ballast w-4-pin module.jpg

Should be the last picture. This and a service manual, you should breeze right through it.
 
I agree with both postings. Especially the grounding part. Myself, I have never had an Orange box fail. I had one that I failed to properly ground when I upgraded my 70 Challenger back in the late 80's. It would run for about 15 to 20 minutes before shutting down just like you turned the ignition off. Then would start again after cooling down. When I finally figured out why it was happening, I checked the ground at the ECU case. Due to the fresh paint on the firewall I had about 40 ohms. Now I make sure I have less than .5 ohms resistance at the ECU and voltage regulator. I have the Orange box on 3 vehicles and no failures on any of them in over 20 years. Maybe I am just lucky but IMO bad grounds cause most of our electrical issues. Check out the upper schematic in post #3. You will see the grounds on the ECU and regulator. Actually, the Alternator, Coil and Distributor case all need grounds too but should be getting a good ground through the engine ground since that is the purpose of the engine ground.
 
I agree with both postings. Especially the grounding part. Myself, I have never had an Orange box fail. I had one that I failed to properly ground when I upgraded my 70 Challenger back in the late 80's. It would run for about 15 to 20 minutes before shutting down just like you turned the ignition off. Then would start again after cooling down. When I finally figured out why it was happening, I checked the ground at the ECU case. Due to the fresh paint on the firewall I had about 40 ohms. Now I make sure I have less than .5 ohms resistance at the ECU and voltage regulator. I have the Orange box on 3 vehicles and no failures on any of them in over 20 years. Maybe I am just lucky but IMO bad grounds cause most of our electrical issues. Check out the upper schematic in post #3. You will see the grounds on the ECU and regulator. Actually, the Alternator, Coil and Distributor case all need grounds too but should be getting a good ground through the engine ground since that is the purpose of the engine ground.

YES....your supposition about grounding is absolutely spot on. Especially the grounding of the ECU. The basic current flow is from the ignition switch thru the ballast resistor to the coil, thru the coil, thru the external switching transistor on the ECU, to ground thru the ECU's mounting bolts. The transistor on the outside of the case of the ECU, turns OFF the flow of current thru the coil to produce the spark. IF the ground connection is poor (high resistance...anything greater than 0.5 ohms), the flow of current to the coil will be lower and subsequently, produce a weaker spark, resulting in a miss or hard start condition. In addition, if the ECU does not have an adequate ground, the voltage spike that is generated by the coil, when the ECU transistor turns OFF, unless adequately grounded thru the case, can and usually results in cumulative damage to dwell determining network, that controls the turn on time of the transistor to begin charging the coil for the next spark. Every failed ECU I've dissected, has exhibited a failed switching transistor and a open diode and transistor in the dwell timing network. (This network processes the distributor's pick-up coil pulse).
A great fix, as suggested, is to run a braided, flexible ground connection from the ECU's case mounting connection to the engine block and for the alternator's voltage regulator as well. Just my thoughts.....
BOB RENTON
 
A friend of mine found some of their orange boxes missing beats untill they stop to work. He removed the black pot on back and found the solded point ground between PCB and case cracked. He resoldered AND installed a ground wire from there to be attached straight to the mounting bolt. Could get to work back some of them.

After the first try, on next one just cut the section of the black pot on back needed to reach this soldering point
 
Funny story time......the last vehicle I had an orange box on was a '71 Chrysler Newport (4dr) that I had installed a 440 and electronic ignition from a '73 Chrysler. This was when the orange box was going bad.
On my way home from work one evening, I was bombing down the freeway, and despite going 70+ MPH, I had a car right on my back bumper. He was close enough I couldn't see his grill! I was looking for a break in traffic so I could move out of his way when it happened........the ECU cut out, and before I had a chance to react, it fired right back up, and detonated BOTH mufflers! :eek: I swear I felt the back of the car lift up, in my peripheral I saw an orange flash, and the idiot that had been on my bumper slammed on his brakes so hard, he almost got rear ended by the car behind him. :p
I didn't stop until I got home, but knew I had blown both mufflers as the car was louder, and the mufflers would hit the road on the slightest dip. Once home, I took a look underneath and found both mufflers blown up to about the size of water melons.......:lol:
 
I got it running, but not totally happy with the fix. First problem was no continuity on one of the wires on the two prong reluctor connector. I ended up slicing the connector rubber and striping insulation and brute force soldered the crimp. Spark came back but was very weak. Key on voltage at the coil was 5V? I noticed a butt crimp at the ballast connector. Again I cut that off and sloppy soldered the wire. Coil voltage was now 8V. HOT Spark returned. Car tried to start and coughed. Bottle feed some gas and it will start and run 10 seconds. I told the guy I would come back in two weeks with my spade lug connector kit, heat shrink, etc and make the fixes pretty and reliable.
Thanks for the help. Take care Bill
 
Sounds like you have the electrical issue solved. Now probably have to deal with fuel issues. Plugged filter or sock. Bad pump? Good luck! At least you are gaining.
 
Photo of the process. Note I printed out the diagrams @Jerry Hall attached.
My trusty Sencore analog VOM has been with me since my TV repair shop days in the late 1970s.

20210409_100312.jpg
 
Funny story time......the last vehicle I had an orange box on was a '71 Chrysler Newport (4dr) that I had installed a 440 and electronic ignition from a '73 Chrysler. This was when the orange box was going bad.
On my way home from work one evening, I was bombing down the freeway, and despite going 70+ MPH, I had a car right on my back bumper. He was close enough I couldn't see his grill! I was looking for a break in traffic so I could move out of his way when it happened........the ECU cut out, and before I had a chance to react, it fired right back up, and detonated BOTH mufflers! :eek: I swear I felt the back of the car lift up, in my peripheral I saw an orange flash, and the idiot that had been on my bumper slammed on his brakes so hard, he almost got rear ended by the car behind him. :p
I didn't stop until I got home, but knew I had blown both mufflers as the car was louder, and the mufflers would hit the road on the slightest dip. Once home, I took a look underneath and found both mufflers blown up to about the size of water melons.......:lol:
What I like about your story, aside from the sorry's you had, is scaring the chit out of the ***-wipe behind you. Some people just gotta ride up da butt crack and I especially don't like it when in my old ride and I'm already going 5 or more mph over the limit...
 
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