Weak spark

[patjamejam]

MY 72 240 stock BABY HAS BEEN DYING ON ME EVERY SO OFTEN, ONLY TO START BACK UP LATER....MOST OF THE TIME! TODAY SHE DIED.....AT THE SHOP... THE MECH WAS TESTING THE SPARK AND SAID IT HAS A WEAK SPARK FROM COIL

HE WAS NOT USING A METER JUST A VISUAL ....

WHY WOULD I HAVE A WEAK SPARK?

Car runs great most of the time, has been doing this dying thing more and more often. PLEASE ADVISE?

Thanks in advance.

Pat

[FastWoman]

Hey Pat,

NO NEED FOR THE CAPS LOCK KEY! WE'LL HELP YOU EVEN IN lower case (which is easier on the eyes)!

I assume you have points ignition. It's not a very complicated system. You could start with the standard major tune-up items, which need periodic replacement anyway:

plugs

wires

points

condensor

distributor cap

rotor

If that doesn't do it, you might also need a new coil and/or drop resistor.

[SteveJ]

If you have a stock distributor with points, the gap and dwell could be off.

[patjamejam]

FastWoman Thanks, I have changed many of those items listed: plugs ,cap wires. Have not changed points, condenser or rotor. Or coil

what and where is the drop resitor located?

Thanks

[patjamejam]

Dave, thanks.Yes Stock Dist. Would the car run most of the time and then die sometimes if gap and/or dwell is off?

The nightmare about this issue is it is intermitent.

[SteveJ]

Okay, I missed the part about it being intermittent. One thing to do would be to check the voltage going into the coil when it's giving you fits.

The problem coming and going suggests heat cycling of some sort. Can you give more details on when the problem happens? Is it after driving a few miles? Stop & go traffic? More information would help.

The "drop resistor" is also referred to a ballast resistor.

[patjamejam]

Stevej

ok Car will start cold great......drive for 5miles to 50 miles stop...not long....starts up but then dies within 2 miles. Always does this after a stop......doesnt descriminated 5min or two hours it will start drive and die within 5 miles . Seems to do it under load....running 70 miles per hour and then it will die....then cut back on a sec later, then die......I throw it in nuet. and it idles but at like 700.....i put it back in gear power foe a sec but then starts cuting out under load.

[patjamejam]

When i say stop i mean turning the car off.

[SteveJ]

Try replacing the coil (and ballast resistor).

[patjamejam]

stevej

got it back from shop, they cleaned up the wiring from coil to dist. (there were some janky connections) of course the car ran .....but time will tell. seemed to idle lower and ruffer.....Also learned i have that petronix inside dist electonic ignition....not points.

Removing the cap the brass rail thing looks worn......the middle is black the rest is still brass......do these wear out?

[FastWoman]

Well, they get tired. You can actually clean the tip of the rotor and the terminals inside the distributor cap, but these parts are fairly cheap, and it's better practice to simply replace them once in a blue moon. Otherwise they get deposits that can short the spark, and the cap can crack.

[patjamejam]

So I looked at this mechs work, he wired it with out anything connecting to the ballast resistor? Is this a major problem ? shorts? The amp meter is bouncing in the + side when driving. please asdvise?