Sudden misfire problem

[Larry P.]

60 283 was running great. Battery went dead and either from charging or trying to start it quit running. It tries to start but sounds like it's running on about 3 cylinders like theres not enough spark.
What should I look for first?
Larry

[Jack H.]

Re: Sudden misfire problem

First, disconnect your battery and fully charge it. Let 'er sit overnight, disconnected after you charge and measure the battery voltage in the AM (SB a touch over 13VDC). You're doing this to make sure you don't have a shorted cell(s) in the battery to eliminate a bad battery as the root of your problems.

If the car then starts & runs, but the problem recurrs, it suggests there's an excessive load (partial short) somewhere in the electrical system that's driving your battery into the dirt. If so, it's time to start troubleshooting to find the source of the drain.

A qualified auto electric shop can make short work of such diagnostics for you if you can drive the car there....

[William V.]

Re: Sudden misfire problem

Two easy things to check come to mind

1. Do you have old gas? Old gas can cause hard starting or no starting and rough running.

2. Check the ballast resistor for an open. If the resistor is open the car will sound like it wants to start but then dies when the key is released from the start mode.

[Larry P.]

Re: Sudden misfire problem

I should have mentioned that I replaced the battery with new. I know about the ballast resister allowing the motor to run until the starter is disengaged. It's more like lack of voltage. Gas not being ignited and it won't run enough to move it. It has been running perfect for 300 miles. All ignition parts are new. Coil, cap, resister, wires, all wireing, frustrating!
I'll start trouble shooting tommorow.
LP

[Roy B.]

Re: Sudden misfire problem

Bad Vacuum advance unit

[Terry R.]

Re: Sudden misfire problem

Check the points,during battery problem could ign. switch have been left on?

[mike cobine]

Back to Basics - Re: Sudden misfire problem

Only two things make an engine run - spark and fuel.

Divide and conquer.

Put a timing light on the coil wire and watch while starting and when it sort of runs. If it is flashing, you have spark. Then check each wire to be sure you have spark on each plug.

If not, then begin checking points, condensor, voltage on the coil positive (+)(about 3-4 v when ON, almost 12 when START). Check the rotor and distributor cap.

If it is a new condensor, replace it with an old one. I have had new condensors fail in the first few hours of service and old ones run through many, many tune-ups. As such, I always took my old points and condensor and put them in the glove box or trunk with a screwdriver just in case. A lot better to run home rough at 3000 rpm max than spend the night on the side of the road.

Gas. Squirt some gas down the carb vent to be sure the bowl is filled. You didn't say how long it rattles along on 3 cylinders, so it is possible it is just not getting any gas. Try shooting some down the carb with a squirt can while it runs. Be sure to watch the tailpipe for black smoke or white smoke.

Make sure the choke is opening. If stuck closed, it will start fine but then just chug along.

If it runs with gas or starting fluid, then you need to check carb inside for the float or needle/seat or check the fuel pump for delivery.

You didn't say what happened prior to all of this other than the battery went dead and then it wouldn't run. Shut off funny? How long had it been running before? Months, days, half hour for break-in?

[george romano]

Re: Sudden misfire problem

Check for moisture inside the distributor cap. Spray it with WD-40 if its wet.

George

[Rob Dame]

Re: Sudden misfire problem

If you find that it is not getting enough gas one of the most overlooked things to check is the filter on the sending unit in the tank. Rob

[Larry P.]

problem resolved

After about 2 minutes of serius trouble shooting the problem is solved.
The air cleaner had rotated and was blocking the choke closed. Sorry, with ALL new parts from gas tank to carb and all electrical, I was frustrated. I guess it's just to easy to lean on you guys. Thanks again for all the help over the years with my project.
Larry

[Rob Dame]

Re: problem resolved

Ya gutta love the easy fix.