Ballast resistor

[Xp29h]

has the OP checked the coil's requirements (presumably an MSD coil and which model) in terms of if a ballast resistor is required, and its value, or not. And can the Chrysler electronic ignition work with the MSD coil?

Great questions! Usually the only time to completely remove the ballast is when installing an MSD ignition box like the 6AL etc.. I don’t know about just coils.. I bet the MSD coil and Chrysler ignition aren’t playing well together.

 

[Nacho-RT74]

damn, too much words and nothing conclusive really said!

first OP hasn't specified the exact setup he has
second OP hasn't said what's the exactly failure

Starts up and stall ? stalls while running the car ? never starts up ?


now, about MSD coil ( blaster 2 ) and Chrysler electronic ignition match. This setup has being run for YEARS on dozens of cars ( including mine ) without a failure related with ballast at least. I have used dual ballast with primary 1 ohm and the "MSD" ballast which is 0.8 ohms. Working good with both. Some pieces will match better than others but doesn't mean will fail.

OP has tested all ballasts and all read good! so IS NOT a ballast issue.

I bet is a WIRING issue.

Bulkhead connections ?
Pickup coil plug connection ?
ECU conection?
some wire internally broken ?

do you have the brake ( and oil if is the case ) light(s) on cluster dimming while cranking ? or do it turns off ?

Do you have voltage at ballast with ign key in RUN ?, do you have the same voltage at blue with yellow trace wire on ECU plug ?, the same but lower voltage at + lead of coil ?

Can you check for continuity in dist wires at ECU plug ? ( it should be on 150-900 ohms rate, but tipically goes on to 250-350 rate )

4 pins or 5 pins ECU module ?

is the ECU correctly grounded with chassis ? you can check it like this:

 

[RJRENTON]

Yes sir, replacement is definitely in the cards - but can that phenomena be directly related to using
the wrong ballast resistor?

Possibly....if the ballast resistor is wrong (too low) MORE CURRENT will flow to the coil's primary winding, producing more internal losses (heat) which, if continued, will ultimately result in failure. Electrical devices do not recover spontaneously, once damaged, will fail eventually.
BOB RENTON

 

[RJRENTON]

Somewhere I read the unsealed ones are called “thermal” and the sealed ones “non-thermal” alowing or not to be affected by the engine bay temperature to provide more or less current per requirements.

Construction has nothing to do with ambient surroundings; it is a manufacturing technique, unless the resistor is purposefully built as either a positive or negative temperature compensated device. Please state the article /source you noted, I would like to know for future reference.
BOB RENTON

 

[moparedtn]

Possibly....if the ballast resistor is wrong (too low) MORE CURRENT will flow to the coil's primary winding, producing more internal losses (heat) which, if continued, will ultimately result in failure. Electrical devices do not recover spontaneously, once damaged, will fail eventually.
BOB RENTON

Makes perfect sense, which makes me wonder why MSD says in their literature that no ballast resistor is required with
these coils at all when used with electronic ignitions?
Perhaps the Mopar electronic ignition operates at similar "juice" as the point type equivalent?
I know when converting older to electronic, the kit from Mopar came with a 0.8 ohm ballast to replace
the stock point ballast with....so maybe I go back with one of those when replacing the coil this time
and the heck with what MSD says?
I mean, what's the harm - slightly less spark to the plugs at worst?

 

[Nacho-RT74]

Construction has nothing to do with ambient surroundings; it is a manufacturing technique, unless the resistor is purposefully built as either a positive or negative temperature compensated device. Please state the article /source you noted, I would like to know for future reference.
BOB RENTON

wil post when I find it... Is just something I remembered have read, not saying by myself is on that way.

 

[Bee1971]

Keep it simple

Inductive ignition systems versus CD ignition systems and there respective matching coils

 

[PolaraFury]

Bought two new ballast resistors. Put 1 on the car and it fired right up. Ran about a minute and it quit running. Would crank no fire.

Put the other new ballast resistor on and it fired right up and seems to be running fine.

thoughts?

 

[PolaraFury]

Side note. The resistor hot to touch

 

[Bee1971]

Hot = Normal

The car should still start even with a bad ballast resistor

It’s when you release the key to the run position and the ballast is bad the car will die

You have wiring issues somewhere else

Ground on ECU Ignition Module

Bulk Head Connector

Volts at positive side of coil

 

[Demonic]

You need to measure the current flow through the ballast. You'll need a DC test meter able to read current. As others said above, something else is amiss, causing the problem.

 

[PolaraFury]

How much current flow am I looking for

 

[RJRENTON]

Bought two new ballast resistors. Put 1 on the car and it fired right up. Ran about a minute and it quit running. Would crank no fire.

Put the other new ballast resistor on and it fired right up and seems to be running fine.

thoughts?

What was the RESISTANCE of the new ballast resistors? YES they will get hot. Using ohm's law E = I X R, given the ohms (resistance), ÷ Voltage drop by the RESISTANCE to find current or E/ R = I. The heat (Watts) generated by the resistor is a function of the current and the resistance or W = I^2 X R. If the current is too great because the coil is incorrect, the resistor will get too hot and burn out.
BOB RENTON

 

[PolaraFury]

Pulled the coil out of the harness and it is a “bit” squished. Apparently someone’s really torqued down the clamp.

installed a new coil.

 

[Ranger16]

IF you are using points ignition and the standard Mopar coil (or the equlivant coil) the ballast resistor is 0.5 ohms. IF you are using the Mopar electronic conversion ignition system ("Orange box") the ballast resistor is 0.8 ohms.

You got me thinking. I am running the Mopar electronic conversion (orange box). It was installed before I bought the car I assume the ballast resistor came with the conversion kit, but could be wrong. Basic black oil filled coil, I just ohm'd it and it reads 0.5 ohms.

Jegs says "1.0 Ohm Ballast Resistor is recommended for most applications on street driven & high performance general purpose applications."

Am I running the wrong resistor? Color me confused.

 

[RJRENTON]

You got me thinking. I am running the Mopar electronic conversion (orange box). It was installed before I bought the car I assume the ballast resistor came with the conversion kit, but could be wrong. Basic black oil filled coil, I just ohm'd it and it reads 0.5 ohms.

Jegs says "1.0 Ohm Ballast Resistor is recommended for most applications on street driven & high performance general purpose applications."
I believe you should use the resistor supplied by the Mopar electronic conversion kit, including the distributor (aka "dizzy") and coil. INCREASING the resistance to the 1.0 ohm suggested by Jegs, will REDUCE the current to the coil and subsequently the high voltage to the plugs.....UNLESS the coil has a higher volts per turn ratio (on the secondary or high voltage side). IMO, the coil must match or be compatible with the ballast resistor and switching device, in this case the Orange box. Jegs says: "...for most applications..." is your application a "most" application? Without a defination of "most" its difficult to say
Am I running the wrong resistor? Color me confused.

Some MSD coils need specific ballast resistors; some MSD coils do not require resistors; some MSD coils are fed directly from the MSD control box with approximately a 400 volt capacitor discharge (CD) pulse to achieve the 40 kilovolt output.
BOB RENTON

 

[Ranger16]

I do not have an MSD coil.

 

[383man]

Some MSD coils need specific ballast resistors; some MSD coils do not require resistors; some MSD coils are fed directly from the MSD control box with approximately a 400 volt capacitor discharge (CD) pulse to achieve the 40 kilovolt output.
BOB RENTON

You are right about the MSD ign as it does not need a ballast resistor at all. As you stated a capacitor pulses 300 to 400 volts into the primary winding when it fires. And I assume for the other coils you are talking about that need ballast resistors is MSD coils made for standard electronic Ign ? Ron