1970 383 in 1969 Charger Not Running Right

[glrestomod]

Hey everyone! I posted previously about some issues I was having with my 1969 Charger not running right. The responses were very helpful and we thought we had the problems resolved, but now they're worse than ever. What's weird is that the more new parts we put on it, the worse it runs. The car sat for 10 years until last June, and I drove it all summer. Once up to operating temperature (160 degrees) it runs rough and wants to die at idle under load. When I get on the gas with any urgency it stumbles and stammers. We have had the carb rebuilt and tuned, put on a brand new alternator, a new voltage regulator on the firewall, 2 sets of new plugs and two sets of new plug wires, brand new battery, we did the amp gauge bypass, new coil, and the ballast resistor was missing and the "jump wire" was getting really hot, so we added a ballast resistor.

The wiring is rough under the hood and behind the dash and it needs rewired, and I have a short somewhere that effects the hood mounted turn signals that I'm trying to remedy. We cannot find a vacuum leak anywhere even though I haven't ruled that out. It has a Mopar Performance black box electronic ignition system that we added on back in the late 1990's. It seems to be functioning just fine according to my mechanic friends who have looked at it.

I'm not sure what else to do. Someone on Instagram posted he had a similar issue with a 440 and as wild as it sounds, he flushed and re-cored the radiator and it fixed his problem which he says sounds exactly like what I'm dealing with. Mine has the wrong radiator (from a 1970 C Body according to the part number) and overheats if I'm in traffic too long because no fan shroud will fit it. When I'm not in traffic it stays at 160 degrees.

Any suggestions would be MUCH appreciated! Thanks in advance to anyone who weighs in and tries to help!

 

[#41]

So to clarify, it runs fine when cold?

 

[glrestomod]

So to clarify, it runs fine when cold?

It actually doesn't, but it isn't so bad that it dies on me at idle under load (in drive or reverse), just when it's up to operating temps. The miss is still there but no where near as pronounced. In park it's pretty rough only when it comes up to operating temps, but the rpm's are high enough that it won't die on me if I don't give it the gas. Sorry! Meant to write that above!

 

[#41]

I did not see your first round, so I may be repeating other's thought here. It's always a crap shoot diagnosing a car from thousands miles away, but here are some ideas/questions:

If your choke is working properly it would have a richer fuel/air ratio when cold. That might be a clue that you have fuel delivery or vacuum leak issue.
Sometimes it can look like its getting spark and fuel, but it may not be enough to run ok past idle speed. Check that the spark is strong (snap!) and that you really are getting enough fuel flow (lines, tank pickup, filter, pump, pump push rod).
You say the wiring is really bad. Try running it with the lights off and see if you see something sparking that should not be.

Other questions:
What do the plugs look like when you pull them and do they all look the same, or is one different indicating a problem with one cylinder?
Does it run good enough to check the timing? Is the timing steady or does the mark jump around?
Have you run a compression test?

 

[glrestomod]

I did not see your first round, so I may be repeating other's thought here. It's always a crap shoot diagnosing a car from thousands miles away, but here are some ideas/questions:

If your choke is working properly it would have a richer fuel/air ratio when cold. That might be a clue that you have fuel delivery or vacuum leak issue.
Sometimes it can look like its getting spark and fuel, but it may not be enough to run ok past idle speed. Check that the spark is strong (snap!) and that you really are getting enough fuel flow (lines, tank pickup, filter, pump, pump push rod).
You say the wiring is really bad. Try running it with the lights off and see if you see something sparking that should not be.

Other questions:
What do the plugs look like when you pull them and do they all look the same, or is one different indicating a problem with one cylinder?
Does it run good enough to check the timing? Is the timing steady or does the mark jump around?
Have you run a compression test?

Thanks for the advice! We have checked the timing and it is steady and holding in place and is about 12 degrees (same as my buddy who has a roadrunner with a 383 and runs perfect; both are virtually stock builds, no big cam, etc.).

The electric choke is working properly according to my carb guy who tested it and tuned it. That makes total sense about the cold start up and the fuel/air mixture. The mechanical fuel pump is working properly as well. No sparking from anything electrical when the lights are on. Forgot to add that I replaced the fuel filter and all of the fuel lines from the top of the fuel pump to the carb. No leaks anywhere that we can find and no fuel smell.

The plugs all looked the same when I had previously pulled them, but I may do that again this weekend just to make sure. I have not run a compression test but definitely plan to!

Thanks a million for the help! Once I've been able to check the things you've mentioned I'll update the thread!

 

[Don Frelier]

It runs fine when the lights are off.

Please explain?

 

[glrestomod]

Please explain?

Sorry! I meant there's nothing sparking, etc. when the lights are on. It actually wants to die quicker/easier with the lights on. I need to go back and edit that comment! I appreciate your help in my previous thread! I pulled the plugs one at a time (my friend did) and the wires. Found out we had a bad set of plug wires! I replaced them and now it still does this rough running and idling and is pronounced and much worse when up to temperature.

 

[RemCharger]

Rough wiring, electric choke, hot wired ballast .. hmmmmm.....
Wonder what @dadsbee would say...

 

[WileERobby]

So, you haven't done a compression test, but you've thrown parts at an unknown problem... I take it you haven't done any vacuum gauge readings, either.

 

[glrestomod]

So, you haven't done a compression test, but you've thrown parts at an unknown problem... I take it you haven't done any vacuum gauge readings, either.

Well, to be fair we didn't really "throw parts" at it, as the voltage regulator went out in the alternator, the fuel lines were old, the carb needed rebuilt as it sat for so long, the wires were old and starting to go bad (according to a mechanic friend), we replaced the plugs as a standard procedure for a car that sat for ten years, etc. Once we did all of that the problem became way more pronounced. So, we did those things not to fix this specific issue (at that time this was very slight and barely even noticeable), but it made this problem much worse the more maintenance parts we replaced for whatever reason. Any input you may be able to offer would be more than welcome.

 

[glrestomod]

So, you haven't done a compression test, but you've thrown parts at an unknown problem... I take it you haven't done any vacuum gauge readings, either.

Also, I don't yet have a way to check the compression. I do have some friends who do and have offered to help, but their schedules and mine haven't yet permitted us to get it done.

 

[Don Frelier]

Maybe recheck the firing order.
Did you look under the cap?

 

[dadsbee]

Rough wiring, electric choke, hot wired ballast .. hmmmmm.....
Wonder what @dadsbee would say...

LOL... Jam the butterfly open and unhook the electric choke.

 

[glrestomod]

Maybe recheck the firing order.
Did you look under the cap?

Yeah, we did that several times. We ended up thinking we had that wrong because it wouldn't start after fixing the firing order. Then, found out the timing was way off after we fixed the firing order. Turned the distributor and it fired right back up! Still has this rough running issue. So frustrating! I appreciate you're trying to help!

 

[glrestomod]

LOL... Jam the butterfly open and unhook the electric choke.

I'm not against that at all if that would fix it lol!

 

[dadsbee]

Humour me and do it...

 

[glrestomod]

Humour me and do it...

I will, and I'll report back! May be this weekend though, but I definitely will

 

[Geoff 2]

What carb? What dist? What is the voltage at the battery, engine idling?

 

[glrestomod]

What carb? What dist? What is the voltage at the battery, engine idling?

The carb is a Holley 600cfm 4160 (Part # 0-80457S from the early 2000's), Mopar Black box electronic ignition kit from 1996/1997, my mechanic friend checked the voltage at the battery and it wasn't correct until after we replaced the things I mentioned above. I can't remember what it was. I'll recheck it this weekend to verify!

 

[Rusty knuckles]

I'm convinced it's a vacuum leak. Have you pulled all the lines off the intake then capped them and see what it does?