66 Dart stutters when under load, sometimes stops when putting in drive.

[Motivator]

Very recently my dart, 225, has been doing this thing where it will "cough" or buck when accelerating. Seemingly it seems to happen more often on inclines, but that may just be me.
Regardless, today it decided its had enough and has drastically upped the antsy. At lower speeds it's a bit of a struggle to keep a steady rhythm, the only "solution" is to keep speed and throttle up. All that really does though is make it power through whatever trouble its having.
At worst though itll stall out whenever I come to a stop. Turning it back over is always easy, however putting it into drive nearly always results in a stall, usually getting out, waiting for a bit and trying again will give me a second chance to limp somewhere... its not optimal, but at least I was able to get back to my house.
Frankly its got me rather confused, and its a bit late to be tinkering with it. However, I intend to figure it out tomorrow! I'm guessing it has to do with fuel delivery (I also have all the stuff to fix fuel stuff, so I hope its that)
I figured it wouldnt hurt to ask if anyone has experienced something similar to this though, thank you all!

 

[RustyRatRod]

Sounds like a fuel issue. I'd start by doing some diagnosis on the fuel system. Have you ever had the tank out and cleaned it out? That's always the first thing I do on an old car. I would remove the tank, remove the line at the fuel pump, blow compressed air through the line to clean it out. Then, remove the line from the pump to the carburetor and do the same. New fuel filter and probably get a rebuild kit for the carburetor. After all that, a new fuel pump probably wouldn't hurt. Jump over to mymopar.com and download a copy of the service manual for your car. I just looked and that's one that they do have. Free download. That will tell you step by step how to work on it.

 

[MadScientistMat]

This could also be an ignition problem. What ignition system is it using - points, stock Chrysler electronic, aftermarket?

 

[Motivator]

This could also be an ignition problem. What ignition system is it using - points, stock Chrysler electronic, aftermarket?

I'm should be rocking the stock system that came with the car, I believe it to be points!

 

[RustyRatRod]

This could also be an ignition problem. What ignition system is it using - points, stock Chrysler electronic, aftermarket?

Therein is the rub. Unfortunately, it could be lots of things. S'kinda why I don't even like answering online problem car threads.

 

[RustyRatRod]

I'm should be rocking the stock system that came with the car, I believe it to be points!

I should have mention that the FIRST thing you should do is check to assure the car is in good tune. Point dwell correc, plugs, wires cap and rotor all in good condition and so on. As Matt said, this could well be ignition related too, so you want to address the condition of the tune and all associated parts. As I mentioned, grab you a copy of the service manual over at mymopar.com. All the tuneup specs are there.

 

[toolmanmike]

Therein is the rub. Unfortunately, it could be lots of things. S'kinda why I don't even like answering online problem car threads.

I am often here:

 

[sam69sat]

My guess is junk in the carburetor. Got a rebuild kit?

 

[RustyRatRod]

I am often here:

View attachment 1716510382

lol Yeah. It's a popular place to be around here.

 

[Killer6]

Very recently my dart, 225, has been doing this thing where it will "cough" or buck when accelerating. Seemingly it seems to happen more often on inclines, but that may just be me.
Regardless, today it decided its had enough and has drastically upped the antsy. At lower speeds it's a bit of a struggle to keep a steady rhythm, the only "solution" is to keep speed and throttle up. All that really does though is make it power through whatever trouble its having.
At worst though itll stall out whenever I come to a stop. Turning it back over is always easy, however putting it into drive nearly always results in a stall, usually getting out, waiting for a bit and trying again will give me a second chance to limp somewhere... its not optimal, but at least I was able to get back to my house.
Frankly its got me rather confused, and its a bit late to be tinkering with it. However, I intend to figure it out tomorrow! I'm guessing it has to do with fuel delivery (I also have all the stuff to fix fuel stuff, so I hope its that)
I figured it wouldnt hurt to ask if anyone has experienced something similar to this though, thank you all!

A sharp jolting hiccup is usually an ignition breakdown, bad wire, fouling plug, carbon tracking in the cap,... failing condensor will start shutting down then 'kick' back in w/a nice unburned fuel bang...lol.
Bad/contaminated fuel, clogged filter, failing pump etc. Be sure to check for fuel in the oil as well, as Slantys will leak into the crankcase before leaking/squirting out the diaphram breather hole.

 

[MadScientistMat]

I'm should be rocking the stock system that came with the car, I believe it to be points!

You'll want to have a look in the distributor. Stock ignition would be points. If that's what you have, make sure they're gapped properly and don't have any wear issues. But after 60 years, it's anyone's guess what might be in there. It could be a factory ignition, but not a 1966 factory ignition. Or a factory ignition, just from another factory. Or an aftermarket module hiding inside a stock distributor. Or even something completely out of left field. So please figure out what you've got here first.

 

[memike]

Looking in my crystal ball...hmmm timing to low, to high or points set to close or far..

 

[Oldmanmopar]

Check the timing chain slack. Could cause many performance issues as described and Its a free and easy check. Take the distributor cap off and turn the damper back and forth to see how much slack is in the chain before the rotor moves. Even a new cheap chain doesn't last very long

 

[slantsixdan]

Tune-up parts and technique suggestions in this post. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. Between those two posts and the links they contain – you'll find and squash the bug.

 

[Motivator]

Of course it wants to rain when its time to do work
My old man and I started chipping at it today. We blew air through the fuel lines, checked the pump/filter, and fixed a small fuel leak from the tank to the hard line.
We also replaced all the spark plugs for good measure.
For the most part, none of that really put a dent in it. The new spark plugs seemed to make things right, but pushing up the hill bogged it down and it stalled out as I was turning around.
Good news though, we took turns dabbing at the fuel mixture and curb idle speeds and that seemed to, at the very least have a decent affect on it. Our last attempt, which was more on the leaner side, was a total struggle bus. The idle was fine, minus the occasional cough, but putting it into gear would almost always stall it. Managing to keep it in gear would result in a need to constantly keep pressure on the accelerator to keep the engine from offing itself.
Its a bit too dark and wet to keep messing with it, but I think ive weened it down to a carb thing or a timing/distributor thing. Hopefully the former, since Ive never messed with the all of that.
Again, thank you all for replying and offering bits of wisdom!

 

[Bewy]

Points ign. The rubbing block wears & retards the ign....which causes problems like yours. While it could be fuel related, checking the points gap AND ign timing is easy to do & should be done FIRST.

 

[Mattax]

OK I'll be the one to say it.

We blew air through the fuel lines, checked the pump/filter, and fixed a small fuel leak from the tank to the hard line.
We also replaced all the spark plugs for good measure.
For the most part, none of that really put a dent in it.

Of course not. Those things wouldn't cause the symptoms described. The small leak could cause them but not under the conditions described.*

The new spark plugs seemed to make things right, but pushing up the hill bogged it down and it stalled out as I was turning around.

But what did the old spark plugs look like?
That's one of the things to look at when figuring stuff out like this.

Good news though, we took turns dabbing at the fuel mixture and curb idle speeds and that seemed to, at the very least have a decent affect on it. Our last attempt, which was more on the leaner side, was a total struggle bus. The idle was fine, minus the occasional cough, but putting it into gear would almost always stall it.

So the idle isn't fine because a properly set idle will be reasonably strong in gear, especially if its non-smog.
1. Find out what is on the car before throwing ideas at it.
You know more than we do. Is it a California car? Any mods?
If you post photos then people here can help with identification.

2. If its stock, then factory specs will work. If parts have been replaced, like MSMatt posted above, then that may change things a bit.

3. Self Help Resources
Scanned shop manuals for most years and Master Technician Service Conference
www.mymopar.com

Master Tech Service Conference Index (go back to mymopar if you want the pdf and youtube version)

Master Technician Service Conference - Chrysler's Training for Mechanics

The Imperial Mailing List Online Car Club is dedicated to the preservation, appreciation and restoration of Imperials and Chrysler Imperials of all years, models and body-styles.

www.web.imperialclub.info

Dealer Info about options, TSB and more
The 1970 Hamtramck Registry Library Page (1965 - 1969)


For a stock tune-up you will need feeler gages, tach, timing light, golf tee, and a way to check dwell is helpful if it has points.

You may also want to pick up an in-line spark checker for diagnoses. They're usually pretty cheap and the easiest way to see if there is spark and roughly judge the quality.

*The fuel pumped from the tank to the carb is simply to replace fuel in bowl. The fuel pump doesn't feed the engine. The bowl supplies the fuel that get's pulled into the airstream. There's some good explanations of a carb works in the Master Tech Conference.

 

[BillGrissom]

My 1969 Dart 225 would idle rough and like to die when leaving a stop. Dealt with that for decades and no mechanic could diagnose it. I was sure it was idling lean. Why I learned to DIY and not trust them (pay $$$ for no help). Still did it after a whole new long-block, so decided it must be the carburetor. The 4th Holley 1920 finally fixed it. It it purr'ed like a kitten at idle, with no stumble off the line, and became a joy to drive. All the others (rebuilt from Auto Parts) were bad. They have a sealed metering block that rebuilders don't unclog (some here know how to blow them out). But you didn't relate what carb you have. The Carter BBS doesn't suffer that problem.

A weak ignition is first noted under WOT at low speed, like trying to accelerate on a freeway on-ramp (when cylinder pressure is highest). My 1996 Plymouth 2.4L started misfiring bad under those conditions. I lowered the spark gap from 60 to 50 mil, per a factory TSB for the turbo engine (not mine), and no more problems. Personally, I wouldn't fuss with points since changing to a GM 8-pin HEI ignition is easy and fixes all, but need a 1971+ e-distributor.

For anyone to help you, you need to give more details, like carburetor, OE points ignition, adjusted valves, changed points and checked gap and measured dwell, ... Another common problem (not yours) is if cold starting is problematic and can't adjust the choke to fix 'er, at least between Winter and Summer. That is often a failed vacuum pull-off. Check the diaphragm is still sound, using a hand vacuum gage or the poor-man's test of push it in and block the vacuum nipple with your finger and see if the rod stays in (will move out slightly then stop).

 

[Motivator]

Oh shoot what a fool I am, I forgot I had this thread kicked up.
Thankfully though, I bear great news! The problem indeed lied with the ignition. Specifically, the points as many have mentioned before. Taking a glance at them before I wasn't able to really see anything wrong with them, but after doing research into how a points and condenser system actually worked gave me the insight to realize "Oh shoot those are supposed to have a gap and are *not* supposed to be burnt out!" Listening to people and doing research really does wonders huh...
Replacing the points and adjusting the timing by feel had things running significantly better, I also checked the valves for good measure, and they were surprisingly in spec... at least I think, a lot of firsts have been happening! After everything was said and done, I took the car to a trusted shop for a proper tune up where they honed in the timing and adjusted the idle accordingly. The dart runs better than ever, so good in fact I'm struggling to get used to it... I keep thinking I'm stalled out at stops because the engine is humming so quietly.
Intermittently the idle will act a little rough, but driving presents no issue. I believe the carb just needs to be cleaned, which will probably be the next order of business. I thank everyone for dropping in and providing insight, I'm learning a lot about how these older engines work; frankly it's all rather amazing.