Electrical problems

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Moparsrul

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I bought a 72 dart that we dumped the gas put fresh in threw it on the charger the battery was shot dumped gas in the carb it started and ran great. We tried to fire it up again and it hasn't run sense. I believe it burned up the Mallory module from the battery charger. I replace the Mallory module, installed the correct ballast resister and a blaster coil. It still wouldnt start. Now it is only getting 9 volts at the brown wire for the 12volt in start position for the coil. changed the ignition switch same thing. I have had Mopars for a long time and have had my share of electrical problems, but this one has wore me out. I will say electrical is not my stong point, but I always fix my own stuff. It has a GM style one wire alternator with wire run to the starter relay. Battery is in the trunk with heavy cables to a isolation block in the front one cable to the starter one to the starter relay. I have checked all grounds and the battery is new and charged. It does have weak spark and will try to start sometimes very first thing but then nothing like something is getting hot? Any help would be greatly appreciated as this is a replacement car for the one my son lost in the fires here.
 
Measure voltage from coil+ to ground with key in "run." You should have less than 12 (assume you still use a ballast?) and that should be about 6--10

Now crank the engine with the key and watch the meter. Should be very close to the same as battery. Measure battery + post also cranking to get that reference.

Don't know why the charger would have burned up the Mallory, did you leave the key on?
 
It has 13.3 at the battery and a the + side of coil with key on when it is cranking it has around 9
 
Is it a 16 V Battery or a 12 Volt battery?
That will effect the readings!
Reread 67Dart273's post carefully. Measure exactly as he describes.
A 12 Volt battery should be above 9 Volts at the battery during cranking.
 
It's a 12 volt battery. I did it exactly as 67Dart273 said. The second time I checked the battery was 12.9 and the positive side of the coil was 12.9 with the key in on position. When it is cranking it has 9 volts. Thanks for the help.
 
Sounds like it has lost the IGN2 leg that gets battery voltage when starting.
 
Moparsrul said:
The second time I checked the battery was 12.9 and the positive side of the coil was 12.9 with the key in on position. When it is cranking it has 9 volts.
Click to expand...
So the battery positive is dropping to 9 volts as well as the coil positive while cranking? If so, sounds like you've got something seriously pulling the battery down during cranking, or a bad battery.

If they are coil voltages (12.9 in run and 9 in crank), to me it seems like the ballast is in the wrong circuit.
 
CFD244 said:
So the battery positive is dropping to 9 volts as well as the coil positive while cranking? If so, sounds like you've got something seriously pulling the battery down during cranking, or a bad battery.

If they are coil voltages (12.9 in run and 9 in crank), to me it seems like the ballast is in the wrong circuit.
Click to expand...
THAT is an interesting thought. Can't happen unless someone has been messin with the wiring. I think at this point I would separate wherever the Mallory gets power and jumper 12V direct to it.

NOTE!!! These voltage readings depend on a factory "like" module. It occurs to me that I do not know if the Mallory draws current when not cranking. For example, a GM HEI module does not, meaning, you can turn on the key, and the coil will not draw current, so the coil connection will read full battery, against the stock Mopar which will draw the reading down.

What I'm saying here, is that I screwed up because for the readings to be meaningful you have to know WHAT IS NORMAL for a functioning Mallory system.

"I don't know."

Hence, hot wire power to the Mallory.
 
The battery is brand new Napa. I have put a new MSD blaster ballast resistor which is correct for the coil it has the same 12.7 v with key on and 9 v when cranking. I'm thinking that I have read some where on here that a certain year jeep starter relay has another tab on it that you can get 12 v only when cranking. That will fix the 9 v that I'm getting out of the brown wire that is supposed to put out 12v when cranking. The question I have is why is the coil getting 12 v thru the ballast resistor with the key on is that normal? As some has touched on. Thanks again for the help.
 
I tried to explain. Read my post.

IF YOU HAVE a module--a WORKING module, the factory Mopar ECU DRAWS COIL CURRENT with the key on/ engine stopped. This means the current goes from key to ballast to coil to ground through the ECU switching wire. This will DROP the coil reading through the ballast

IF YOU WERE to use a GM HEI WITH a ballast, it WOULD NOT do this---because under same conditions, the HEI does NOT draw coil current. There is nothing to DROP the ballast voltage.

As I said earlier, I DO NOT KNOW if the Mallory is this way

Possibilities?

Miswired?
The module is no good?
The module is not grounded?
The module works like an HEI and does not draw coil current when stopped?

This is why I suggested "hot" wiring the ignition to bypass the ballast and harness, then you can concentrate on the trigger device, the module, coil, and power to the ignition system.

Do a search and find the Mallory web info on troubleshooting.
 
So getting back to this voltage issue. I tried running a 12v hot to the coil no start. The wiring on this car has been messed with pretty good. I have cleaned up all of of the bad connections that I could find. I have done the mad wiring like the show. Like I said before it has a one wire alternator. Still only had 9.5 coming out of ignition 2 wire from the ignition switch out in crank position. Replaced the ignition switch same thing no change. I have installed a new starter relay for a Wagoneer with the extra lug that my understanding is will give you 12 volts at cranking. It is the same 9.5 volts when cranking from that as well. From everything that I have read ignition 2 should have 12v when cranking? Im sure it is not theonly problem because it didn't start with a hot 12v but one thing at a time . Like I have said before wiring is not my best attribute, but I can usually get there. Thank ahead of time for any help.
 
What you say about the later start relay is true, and if it is only giving you 9.5, then you need to check right at the battery when cranking. If the battery is "let's say" 11 and the relay 9.5, you have a gigantic voltage drop somewhere

Having said that, the later relay should not be needed. I would not stray too far with modifications, that is,some of us have a saying, "fix what is there." What that means is, it did work, and sometimes making mods can ADD problems and REALLY throw you off

Did you try "hot" wiring to the coil from the battery?
 
Problem, of course, is "we ain't there" (can't see.). Might be time to see if you can scare up some local help. HAS to be either a Mopar guy or at least someone who understands auto wiring around you.
 
Not sure what the Mallory is? Pictures would be nice.

There is a lot simpler easier way to do this that runs straight 12v and no Ballast Resistor.

☆☆☆☆☆
 
Screenshot_20230615-031145_Gallery.jpg


Screenshot_20230615-031217_Gallery.jpg


Need a true E-Coil where the above Yellow Coil is pictured, to make it work correctly with the HEI module.

Screenshot_20230615-031115_Gallery.jpg


Nice simple 2 post E-Coil + and - these are what the '95 Ford F150 use.

Works great, works simple, quicker starts than Mopar Electronic Ignition and the spark plugs burn cleaner with the much higher voltage e-coil.

☆☆☆☆☆
 
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