[caball]

I have a 1971 dodge Challenger 318 auto with a electronic ignition. The car stumbles and stalls when you come stop. It will restart easily but if you sit in gear at a light or in gear it will stumble and stall. I can turn up the idle and that seems to keep the car from stalling. I rebuilt the carb with a new fuel filter. I have replaced my electronic ignition without any improvment and exchanged my distributer. I have also checked for vacume leaks around the carb and replaced my vacume lines still without fixing the stalling problem. I hope someone here may have a solution.

Thanks Carl

 

[Bob Lincoln]

Welcome to Allpar!
Will it still stall in neutral, or only in drive? If it stalls in neutral, try idling it while monitoring battery voltage to see if it's normal while idling (should be about 13.5 to 14V).

Did you rebuild the carb in response to the problem, or did the problem start after you rebuilt the carb?

 

[caball]

Welcome to Allpar!
Will it still stall in neutral, or only in drive? If it stalls in neutral, try idling it while monitoring battery voltage to see if it's normal while idling (should be about 13.5 to 14V).

Did you rebuild the carb in response to the problem, or did the problem start after you rebuilt the carb?

I rebuilt the carb because of the problem and it runs fine in neutral. It only stalls after the engine gets hot, at a stop while in gear.

 

[Bob Lincoln]

That could be a vacuum problem, a misadjusted float or idle mixture screw, ignition timing or a host of other problems.

What is the engine vacuum while idling in Park, and is it steady or does it flicker?
What did you set the ignition timing to?
Have you ever checked the reluctor gap in the distributor, and if so, what did you set it to? Did you make sure to use a non-magnetic feeler gauge?

 

[caball]

That could be a vacuum problem, a misadjusted float or idle mixture screw, ignition timing or a host of other problems.

What is the engine vacuum while idling in Park, and is it steady or does it flicker?
What did you set the ignition timing to?
Have you ever checked the reluctor gap in the distributor, and if so, what did you set it to? Did you make sure to use a non-magnetic feeler gauge?

I will have to check the vacum, the timing is 3 btdc and I have never adjusted my reluctor gap. I have had the car for 20 years and never had this trouble.

 

[KOG]

Heat riser valve stuck closed?

 

[thebluesguy54]

I also suspect a vacuum problem and it can happen at a stop sign with your foot on the Brake. Could be the brake booster is leaking vacuum internally. To find out you can pinch off the line going to it, vice grips or a c-clamp will work , now in the drive way put it in gear and use the safety brake and see if istill stalls if it doesn't then it's your brake booster or the line going to it.

 

[caball]

That could be a vacuum problem, a misadjusted float or idle mixture screw, ignition timing or a host of other problems.

What is the engine vacuum while idling in Park, and is it steady or does it flicker?
What did you set the ignition timing to?
Have you ever checked the reluctor gap in the distributor, and if so, what did you set it to? Did you make sure to use a non-magnetic feeler gauge?

My vacume is about 20 idling in park and steady, my timing is 3 btdc, I have never messed with the reluctor.

I also suspect a vacuum problem and it can happen at a stop sign with your foot on the Brake. Could be the brake booster is leaking vacuum internally. To find out you can pinch off the line going to it, vice grips or a c-clamp will work , now in the drive way put it in gear and use the safety brake and see if istill stalls if it doesn't then it's your brake booster or the line going to it.

I plugged my vacume lines to the brakes, pvc, distributer and the air cleaner, used a vacume gauge also. The vacume is steady and the engine still stalls when it gets to operating tempurature and when I put it in gear.

 

[Bob Lincoln]

Just to eliminate it, check the reluctor gap. It may not have been set correctly on the new distributor. Spec should be .008 inches.

Also check voltage at idle in park and in gear (with brake set for safety).

It probably still is a carb or air/fuel mix issue, but let's rule out other things. KOG's suggestion is a good one, with the engine cold, check to see if the heat riser valve is stuck. If it's stuck in the cold position (supplying heat when the engine is warm), it can cause a vapor lock condition in the intake. Driving lots of short trips tends to make the valve stick in this position.

 

[CudaPete]

Check the vacuum advance for the distributer.

 

[Bob Lincoln]

I forgot to mention the obvious: first be sure that a full tuneup was done within the last 15K miles or so - plugs, wires, cap, rotor, air and gas filters, PCV valve, clean breather cap.

 

[caball]

Check the vacuum advance for the distributer.

I have checked the heat riser and it moves freely. It has had a tune up with all the above parts.
What is the best method for setting the air fuel mixture?

 

[Bob Lincoln]

Put a vacuum gauge on a port that always has full vacuum (below the throttle plate). Turn both mixture screws in fully (without crushing them in), then back off 2 full turns each. Start the car, let it warm up fully so that the choke is fully open. Slowly adjust both screws in equally in tiny increments, until the engine just starts to stumble very slightly,and the vacuum needle begins to bounce or move unevenly. Then back both screws out equally just enough to get the vacuum gauge needle steady - no pulsing and no engine stumbling. The idle should be smooth at this point. Then set the fast and the hot idle speed screws to specification.