ignition issues

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schwinger

schwinger

1972 Dodge Dart Swinger
Joined
Jun 24, 2008
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Location
Fresno, California
having trouble figuring this problem i have. car starts and idles good but after a couple minutes ballast and coil heats up to where i believe it kills the car.

Its getting fuel, new filter, new fuel pump, carb is good, new sparkplug wires, spark plugs, fairly new distributor, alternator, voltage regulator, coil and battery. Started throwing new parts to it and it hasnt solved the problem.

Points type distributor, and its a 318. Problem started ever since i replaced the distributor with a new one and already went thru 2 new distributors.
 
I'd start by checking the voltage at the battery while the car is running. It should be about 14.2 with the car at a fast idle. If that's ok check the voltage at the coil, it should be a 2-3 volts less because it gets a voltage drop through the ballast resistor.

Throwing parts at a problem is an expensive way to troubleshoot anything!
 
Ballast resistors DO run hot, so that part may be/ is probably normal. RIGHT when the car dies, check the spark. Do this cranking WITH THE KEY, not jumpering the start relay, and if you have spark, and fuel, it should fire.

If it starts "on the key" and dies, THEN suspect the ballast

Might be the coil going bad, this is classic, but I'd try and find a used coil and throw on there before I spent money on a new one.

There is very little in a distributor to cause this----

If the dist. bushings are not overly sloppy, if the points gap/ dwell holds steady, and IF IF IF the condenser is good ("new" does not mean "good") then that part should be OK.

Check your voltage at the 'dark blue' going to the ignition resistor. To do this, turn the key to "run" with engine OFF Use your meter and stick on the dist. NEG post. IF you get battery voltage, bump the engine until the voltage goes low. This shows that (and you want) the points CLOSED

Now put one probe directly onto the battery positive post, the other probe on your "dark blue" connection at the ignition ballast resistor. This is the side with ONE wire connected

You are looking for a VERY low voltage, and over 1/2 volt is too much

(You are measuring the drop from the battery through the harness connections to the ignition.)

To double check this reading, read the battery voltage carfully with your meter

Now check the "dark blue" to engine block, and compare the readings. Once again, there should be an absolute maximum of 1/2 volt difference.

If there is a big difference, this shows a bad connection somewhere from the battery, fuse link, through the bulkhead connector, through the ammeter circuit, the ignition switch connector, the switch, and back out the connector, and then back OUT the bulkhead connector on the 'dark blue' line.
 
ill check it out and hopefully find this problem. also if a condenser is bad would that cause a short to ground? and also when i had the distributor out but wires still connected and when i had the key in the on position the housing on the distributor was sparking like crazy when i touched it on the valve cover and brake master cylinder
 
The points ARE a "switch to ground." So if you had the distributor out and the key on, and the POINTS WERE CLOSED, it certainly would spark to ground, the circuit is.....

ignition switch---ballast----coil----points----distributor housing------ground

If the condenser was bad enough that it was shorted, the car would not run at all.

A point ignition MUST HAVE a good condenser to make spark.

I misread your post. You said the coil heats up as well. Coils do run "pretty warm" but after a couple minutes of idle, you should still be able to put your hand on it for at least a short time.

This IS classic "coil going bad" behavior. I stick by this:

I would normally say replace the condenser, but you say your have replaced the distributor (more than once.) It PROBABLY is the coil. Try to find a used one (cheaper) to try, and if that fixes it, buy a new one.
 
Throwing parts at a problem is a great way to fix electrical problems, just use cheap junkyard parts like I do. I have 3 used ignition coils on the shelf. The only way to operate a classic car easily is to have a well-stocked garage. I do the same for my newer cars, buying new parts when I see a good deal. Nothing like grabbing another starter off the shelf and driving again in 15 minutes. Of course, if you live in an apartment it isn't easy. I have had friends who had a whole engine and transmission ready to go.

To check spark problems, buy the in-line spark tester from Harbor Freight ($3 on sale). I have one in the trunk of all my cars but the diesels (guess why). I just used it last Sunday when my Newport died coming home from church. I thought the erratic Holley Pro-jection TBI, but turned out to be no spark. I had a backup Crane XR700 ignition box in the trunk ($15 off ebay). Hooked it in, good spark, and drove home. What would a tow have cost?, plus no wasting hours on that.
 
67Dart273 said:
I misread your post. You said the coil heats up as well. Coils do run "pretty warm" but after a couple minutes of idle, you should still be able to put your hand on it for at least a short time.

QUOTE]

Coil burns up after a couple of minutes of idle and when i rev it at first it cuts out then gets worse then dies. its a new coil too unless that took a crap but ill double check it and hopefully i can get this sucker running tonite. also i went thru 2 coils, i putted an msd blaster then started having problems, tested it and it went bad, had my stock one so i but that one back on, ran good for a week then started running like crap again, and left me stranded, went to napa to get a new on and installed it. didnt even want to start. had to replace the battery because it was going bad and now it idles but dies.
Click to expand...
 
This is starting to sound like an OVERCHARGING (overvoltage) problem. Did/ does the battery bubble and puke out the vents?

There is absolutely NO reason to go through more than a random couple of either coils or resistors Hell, in my LIFETIME (I'm 64) I don't think I've replaced more than 2 or maybe 3 bad coils on my own cars.
 
no it doesnt, but i didnt have an overcharging problem before, but now since i put in a new alternator in and rewired the wiring to the alternator its overcharging now so i think i got my wiring mixed up.

CHecked voltages thru the balast like you said and its 10.60 volts key on from 12.15 battery voltage and the voltage from - side of coil to engine is .595 and + side from battery to ballast dkblu side is .832 volts

cHecked coil resistance and its 8.62k ohms from - to middle coil post thingy and 1.3 ohms - to + which i believe is ok.

also the wiring diagram shows that my ignition goes thru the horn buzzer which i dont think its right and its an old reproduction wiring diagram from john or james something osborn reproductions thats for a 72 dodge dart but i dont think its right so i took out those wires and it started running better but cuts out laterer
 
schwinger said:
+ side from battery to ballast dkblu side is .832 volts
Click to expand...

WAY too much voltage drop. You have a bad connection somewhere, either (most probably) the bulkhead connector, or the ignition switch connector or the switch itself

THAT 8 tenths of a volt (damn near 1 volt) CAUSES overcharging when the car is running, because it also feeds the regulator along with the ignition. So the regulator, let's say it's at 14V where it belongs, just ADDS that 8 tenths of a volt onto it's own regulating point.

So instead of charging at 14V where it belongs, it will run nearly 15 volts

This might NOT be causing the immediate problem with your ignition, but it won't help

Now measure the battery voltage with the engine RUNNING at a "simulated cruise" RPM and see what the voltage actually is.

By the way, you don't have a situation where you or someone goes around leaving the key on, do you?
 
connections to the bulkhead, were rusty/crapy looking so ill clean them up or replace a few and go from their. Replaced the ignition switch and lock that narrows it down to the connections then. but ill check it when its running like you said and get this figured out soon.

i dont leave the key in the on position alot only listening to the radio with the key turned to accesories or oposite way once in awhile and i dont let anybody else drive my car.
 
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