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My Charger seems weak this year - part 1 ignition system check

furious70

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Trying to go through the subsystems to see if I can find the cause of a general weakness all around. So I started looking at ignition:

1. Cap and rotor do have wear but nothing I think should be causing problems. I'll probably replace since that's simple and affordable.
2. I tested continuity on my wires. They all were between 1500-2500 ohms depending on length which seems good. One of them got burned several years ago and is taped up but the continuity was one of the best so it should be fine?
3. Plugs - tested continuity and they seem fine and I don't get a reading on the porcelain. They are XR5's instead of 4's, I don't remember why. It's a 67 440 short block with 516's on it. Do these pictures look like the right heat range?

The net of it is I don't see anything in the ign system that stands out as a problem

PXL_20210608_004608948.jpg PXL_20210608_004553576.jpg
 
Sounds like you've had it hibernating for the winter? If that's the case the first thing I'd be looking into would be the fuel and fuel system/carb/tune. But it doesn't hurt to re-verify your timing settings even if you haven't touched them.
And honestly if it were me (and I'm cheap lol) since you've got the plugs out, I'd replace them and that taped-up wire. The resistance reading at rest is fine but under operating condition things are getting hot and moving all around... it *could* be causing an issue.

I don't believe the one step colder plug is hurting you; it's hard for me to see the coloring on the threads but too-cold plugs will generally build up more deposits and yours appear pretty clean.

I will say though, I can swap out my Pertronix Flamethrower coil for my spare (known-good) standard Accel coil and the start-up and idle sounds noticeably weaker. And that's with either the FBO or Mopar ignition box. So maybe it's time for a new/better coil...
Good hunting!
 
it's got an orange box ECU and a MSD blaster 2 coil. They are both a decade old. I don't have spares of those to swap in quick unfortunately.
The plugs are clean, I was actually surprised they were 5's. It pings on 87 so I have to run 93 so I think you're right on staying with the 5's.
I did fight the 750 double pumper getting it out yes, I do want to get back around to that but there was nothing that seemed wrong other than the stuck rear float.
 
Okay, sounds like it just needs a good tune-up. If you know, or have reference of, your vacuum readings from when the engine was running better you can compare then to now. That will give you an idea of the carburetor's current state of happiness.
 
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