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Timing marks jumping around

 
Old 02-13-2019, 06:09 PM
  #16  
Mrmerlin
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did you pull the rotor off and look for the small roll pin that holds the inner fingers
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Old 02-13-2019, 06:10 PM
  #17  
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The erratic advance generally won't cause a misfire, but it will contribute to sluggish performance and the erratic timing you report.

The RPM-limiting rotor can cause a misfire if there's internal damage. Verify the part number and do some searching for whether the one you have is a RPM-limiting version. In those, there's a spring and a sliding weight that open if they are spun too fast. Worth at least a look.

Otherwise... Inspect the green wire carefully for kinks and connector issues. There's nothing "smart" about the system that screws up. It's all mechanical in the distributor and electrical from the distributor to the box, the coil, and back. Known wear pieces include the green wire on the low side, then the ignition wires and spark plugs on the high side. The cap and rotor can easily play a part in a misfire especially if the cap is cracked or is suffering from "carbon tracking" inside; any metal or carbon deposits on the inside of the cap should be completely removed (soap and water), and then inspected for cracks.
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Old 02-13-2019, 06:19 PM
  #18  
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Originally Posted by Mrmerlin View Post
did you pull the rotor off and look for the small roll pin that holds the inner fingers
Actually forgot to look at that - I will pull it off again tonight and double check.
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Old 02-13-2019, 06:24 PM
  #19  
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Originally Posted by dr bob View Post
The erratic advance generally won't cause a misfire, but it will contribute to sluggish performance and the erratic timing you report.

The RPM-limiting rotor can cause a misfire if there's internal damage. Verify the part number and do some searching for whether the one you have is a RPM-limiting version. In those, there's a spring and a sliding weight that open if they are spun too fast. Worth at least a look.

Otherwise... Inspect the green wire carefully for kinks and connector issues. There's nothing "smart" about the system that screws up. It's all mechanical in the distributor and electrical from the distributor to the box, the coil, and back. Known wear pieces include the green wire on the low side, then the ignition wires and spark plugs on the high side. The cap and rotor can easily play a part in a misfire especially if the cap is cracked or is suffering from "carbon tracking" inside; any metal or carbon deposits on the inside of the cap should be completely removed (soap and water), and then inspected for cracks.
Will check into the RPM limiting and report back -

The Cap, Rotor and Wires are all brand new and appear to be in good shape. Is there any way to test the green wire? - I have done some searching and cannot seem to find any info on this.

thanks again for all the help here guys.
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Old 02-14-2019, 12:02 AM
  #20  
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So the misfire was there prior?
Is the engine surging or any misfire with the timing change?
If not.....
You’ve replaced everything else.
Green wire.
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Old 02-14-2019, 02:38 AM
  #21  
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Oh, wait a minute! This car has a spark box mounted on the inside fender well, right?
BradW's street beast 82 has a bad misfire at off idle RPMs that we (the collective we) found with an ocilloscope. The ignition signal just completely deteriorated at the same time as the misfire. We replaced that spark box with an extra I had (for some unknown reason)and never looked back.
I had never heard of one of these going bad before that time. The problem only happened beyond a certain RPM.
If all else fails, check that spark box.
Good Luck.
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Old 02-14-2019, 01:31 PM
  #22  
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I won't be able to get back into this until the weekend now. I will do some more checking then and report back.

Just to confirm - It seems to me this is for sure some kind of electrical issue - do you all concur ? Is there any way this could be an air/fuel mixture issue ? I want to make sure Im not going down the wrong path here
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Old 02-14-2019, 09:51 PM
  #23  
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It can easily be an air/fuel issue.

Troubleshooting is a process of elimination. The selection of what possible causes to eliminate is important. Electrical, at least for me, is the easiest to diagnose and eliminate. It's also the most common cause of odd running in my experience, if you disregard storage-related issues. I have a hammer, and all my problems look like nails.
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Old Yesterday, 10:23 PM
  #24  
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I would remove the connector from the computer on the fenderwell and put deoxit 100 on it then plug it back in,
same for the green wire connections.

Also pay close attention to the fingers inside the distributor,
if one of them is bent then it can hang and make the dizzy seem dizzy best to turn the engine over by hand to observe the operation of the distributor,
and confirm the roll pin is in place.
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