Passed Down 72 Charger Need Some Help Diagnosing

[Mike Dorn]

Hi Everyone, need some help diagnosing what’s going on here, essentially it sounds like a backfire but happens every motor rotation, not sure what’s really going on my first thought was timing but any help would really be appreciated. My background is electrical stuff but this has me stumped. I have linked a video below of what it’s doing

Thanks in advance!

 

[diesel_lv]

Your video hasn't downloaded yet. So, guessing here but 2 possibilities. Distributor 180 out. Easy check, pull it and install 180° and try it. Other is firing order. Small block rotates clockwise. Check that wires are in correct order and clockwise.

 

[davek]

I would check your wires first

 

[Red63440]

I am in full agreement with diesel_lv… have you changed spark plugs or spark plug wires? Had you pulled the distributor for any reason? A possible 3rd reason could be that the timing chain is stretched and has jumped. The firing order is cast into the intake manifold and general info is available on the internet.

 

[Mike Dorn]

Your video hasn't downloaded yet. So, guessing here but 2 possibilities. Distributor 180 out. Easy check, pull it and install 180° and try it. Other is firing order. Small block rotates clockwise. Check that wires are in correct order and clockwise.

Thank for very much for the info, something weird happened with iCloud I changed the link to one that works, it’s is a 440 and what’s really stumping me is that it used to run fine then started having this issue, put a few thousand miles on it and ran smooth prior to this. Video should be good now if that’ll help.

 

[Mike Dorn]

I would check your wires first

I pulled and cleaned each plug and tried to inspect each wire as well, could they be damaged even if there’s no visual issues?

 

[Mike Dorn]

I am in full agreement with diesel_lv… have you changed spark plugs or spark plug wires? Had you pulled the distributor for any reason? A possible 3rd reason could be that the timing chain is stretched and has jumped. The firing order is cast into the intake manifold and general info is available on the internet.

Ignition components were my first thought as well, plugs are newer but I cleaned them just in case, would be be worth it to grab a new set of wires to remove that as a potential issue?

 

[Red63440]

Did you do each plug one at a time or one side at a time. It sounds like the wires are crossed, you may want to check them just to make sure.

 

[Mike Dorn]

Did you do each plug one at a time or one side at a time. It sounds like the wires are crossed, you may want to check them just to make sure.

I did one at a time, pulling one wire and one plug each go, I was hoping there was an obvious plug/wire issue but no luck, the issue started prior to any plug/wire removal

 

[davek]

I meant did you check the firing order on the wires/cap? Do you know if the car ran before you got it?

 

[davek]

for some reason I cant get the video to play.

 

[Mike Dorn]

I meant did you check the firing order on the wires/cap? Do you know if the car ran before you got it?

Yep ran fine about 4 months ago, no changes or new components just started doing the misfires in the video, to me sounds like a misfire on 1 cylinder every rotation but not sure as to what could cause it. I saw it running perfectly prior to the issue.

 

[Mike Dorn]

for some reason I cant get the video to play.

https://youtube.com/shorts/DDSDG5rFRfM?feature=share

I uploaded it to YouTube, let me know if that helps, and thank you!

 

[Red63440]

Do you know which cylinder? Maybe pull the valve cover and check things once you know what cylinder. Check your wires and firing order, it’s spitting through the carb on the video.

 

[Mike Dorn]

Do you know which cylinder? Maybe pull the valve cover and check things once you know what cylinder. Check your wires and firing order, it’s spitting through the carb on the video.

Not sure which cylinder, could be a dumb question but is there a common way to determine which cylinder? Definitely looks like it’s spitting on only 1 cylinder every rotation

 

[davek]

What carburetor is on that car?

 

[NoCar2023]

Valves binding after sitting for a while—now has bent pushrod?
If you are confident the firing order is correct—pull the valve covers.

 

[Red63440]

The spitting is being caused by the engine firing on the intake stroke and it blowing through the carb. It’s being caused by the timing either through a crossed wire or in the distributor, pull the valve covers like I said earlier and check for possible bent pushrods.

 

[Mike Dorn]

What carburetor is on that car?

Currently a Holley sniper but had an edelbrock carb on it and both don’t effect the issue

 

[davek]

bad gas?