Bad Coil?

[RJRENTON]

How was the wiring harness ends that connect to the Ballast Resistor itself

Just you removing the wiring from the old to new resistor could have been enough to cause a connection for voltage to the positive side of coil

With the correct ballast resistor, in normal operation, the resistor runs extremely HOT. It is very possible that because of the heat generated, that the resistor's internal connections to the male wiring harness connectors have become oxidized possibly causing the "no start when hot" condition. Since you have replaced the resistor with a spare, has this fixed the problem?
BOB RENTON

 

[Bee1971]

Let me ask this, what happens if you use a regular coil instead of one made for electronic ignition, the answer may help to explain the problem.

Chrysler used the SAME ignition coil with electronic ignition thru 1978 as it did with points systems earlier , like from the 50s and 60s

 

[Red63440]

With the correct ballast resistor, in normal operation, the resistor runs extremely HOT. It is very possible that because of the heat generated, that the resistor's internal connections to the male wiring harness connectors have become oxidized possibly causing the "no start when hot" condition. Since you have replaced the resistor with a spare, has this fixed the problem?
BOB RENTON

it now starts great every time but it will be something I keep my eye on in the future. The new ballast resistor plugged in nice and tight. The car came from Las Vegas where it was kept inside under a cover so the contacts on the resistor were clean and appeared as new.

 

[HALIFAXHOPS]

Just a FYI Make sure the ballast resistor has the proper ohm rating they have them from .25-1.5 ohms and all look pretty much the same in the two pin. Four pin are always right out of any box. .5/1.2 ohm that I have seen.

 

[moparedtn]

Chrysler used the SAME ignition coil with electronic ignition thru 1978 as it did with points systems earlier , like from the 50s and 60s

Thanks, that gets me halfway there. Now, what was the rating of the factory ballast on the Mopar electronic
ignition?

 

[HALIFAXHOPS]

 

[Bee1971]

Thanks, that gets me halfway there. Now, what was the rating of the factory ballast on the Mopar electronic
ignition?

Like Hops listed

Factory Dual Ballast Resistor

.5 OHM on the Ballast Resistor for the Positive side of Coil in the run position of ignition switch

The other side of the Ballast Resistor was for the fifth pin on the ECU/Ignition Module
Was typically a full 5 OHMs on that side of resistor

That’s why Chrysler inserted pins on there wiring harness connectors and put holes in there Dual Ballast Resistor

So you couldn’t reverse the wiring connectors by accident and flip the OHM Resistance which would have damaged the ECU/Ignition Module going thru that fifth pin

Trying to find a .5 OHM Resistor in the Factory Dual Ballast Resistor is next to impossible for the positive side of coil

All after market Dual Ballast Resistors are in the 1.2 OHM to 1.8 OHM Resistance on the positive side of coil

If you can find a Factory correct Mopar part # 3656199 Dual Ballast Resistor
It will have an open back on that side of resistor exposing the element

And have the part # stamped in the Front of Resistor in the porcelain
And will BEE rated at .5 OHM



Anyways if you want to run a Single Ballast Resistor

Almost 100% of Chinese / Mexican ECU/Ignition Modules only run 4 pins

That’s why you can get away with a single side Ballast Resistor - And you have much more easier choices of OHM Resistance values in all shapes

.25 OHM all the way up to 1.8 OHM

FACTORY CORRECT IS .5 OHM RESISTANCE on the Positive Side Ignition Coil

Are we confused yet

I need my coffeee eeeeee

 

[Bee1971]

Just a FYI Make sure the ballast resistor has the proper ohm rating they have them from .25-1.5 ohms and all look pretty much the same in the two pin. Four pin are always right out of any box. .5/1.2 ohm that I have seen.

5 OHM and 1.2 OHM

Just a little correction Boss

 

[Red63440]

I have a single plug on one side and a dual plug on the other, the dual plug does have the pin so which is correct for my installation?

 

[Bee1971]

Can you snap a picture ? Do you have an OHM Meter

A little confused on what your saying - Sounds like a Dual Ballast Resistor wiring harness got cut on one side and converted to single maybe ?

Obviously in 1964 your car came with a single ballast resistor for points

Take a picture of your Ballast Resistor and ECU / Ignition Module

 

[Red63440]

Im pretty sure its an after market set up.

 

[Bee1971]

When I blow up your picture it’s a little blurry looking at wiring so it’s tough to see

But your harness looks pretty factory original and they just added or plugged into that dual ballast side of connector on that one side for the ECU / Ignition Module power and it looks like a hack job which would explain your issue of starting

Based on what I can tell - You have a four pin ECU - You can verify by unplugging the large black rubber connector and counting the pins on ECU

Anyways if that’s the case you could really clean up your wiring on that Left side of the Ballast Resistor and eliminate that dual pin connector that’s not needed

 

[Sixpactogo]

All that pretty white paint on your inner fender where you orange box is mounted is probably causing all of your woes. If that box doesn't have a less than .05 ohms from the case to neg post on the battery, it will get hot and open up until it cools down. Happens all the time. Paint is not a good ground. I hear guys whining about the orange box failing when more than likely was too much paint under the mounting screws.

 

[moparedtn]

Like Hops listed
Factory Dual Ballast Resistor
.5 OHM on the Ballast Resistor for the Positive side of Coil in the run position of ignition switch
The other side of the Ballast Resistor was for the fifth pin on the ECU/Ignition Module
Was typically a full 5 OHMs on that side of resistor
That’s why Chrysler inserted pins on there wiring harness connectors and put holes in there Dual Ballast Resistor
So you couldn’t reverse the wiring connectors by accident and flip the OHM Resistance which would have damaged the ECU/Ignition Module going thru that fifth pin
Trying to find a .5 OHM Resistor in the Factory Dual Ballast Resistor is next to impossible for the positive side of coil
All after market Dual Ballast Resistors are in the 1.2 OHM to 1.8 OHM Resistance on the positive side of coil
If you can find a Factory correct Mopar part # 3656199 Dual Ballast Resistor
It will have an open back on that side of resistor exposing the element
And have the part # stamped in the Front of Resistor in the porcelain
And will BEE rated at .5 OHM
Anyways if you want to run a Single Ballast Resistor
Almost 100% of Chinese / Mexican ECU/Ignition Modules only run 4 pins
That’s why you can get away with a single side Ballast Resistor - And you have much more easier choices of OHM Resistance values in all shapes
.25 OHM all the way up to 1.8 OHM
FACTORY CORRECT IS .5 OHM RESISTANCE on the Positive Side Ignition Coil
Are we confused yet
I need my coffeee eeeeee

Thanks for the reply and yes, HH is always a great help in all things electrical - and that chart is well known,
of course - but it doesn't really help when it lists several different impendences for the same ECU, nor for
different coils with the same this or that - not to mention, there's no years or engine applications listed, either.
I always took that to mean you had a window of acceptable ballasts for those same units, since that's what
the chart indicated....not much help when you want to know what MOPAR actually sold in the conversion kits.

Yes, I'm making a big assumption that what Ma sold was correct out of the box here, but I'll go with it if I can
find out what the heck it was...
And by the way, the Mopar "performance electronic ignition conversion kits" used a single ballast and in the
instructions, it specifically says how to wire a car that had a dual ballast to it, that those were "unnecessary".
I've got a copy of the installation instructions for the old kits (well, the ones being made in the late 70's,
anyways) in PDF format that I could probably copy/paste into a large post on here if anyone would like
to see it.
Unfortunately, it does not specifically list individual kit components by part number (or by rating, in the case
of the ballast). I have been told by a couple folks who should know that the ballast in those kits was 0.8ohm
rated - it would just be nice to know for sure.

Another thing that interests me is the reference by more than one that we must use a coil made specifically
for electronic ignitions, when I just saw again that Ma didn't change coils from the 60's on to 1978??
Same coil, whether points or ECU eh?

As an aside, I've been playing around on the Standard Ignition website (great source of info since 1919!)
For my 1968 (standard points), it shows for a stock ballast:
Part # RU-4 (single ballast)
Cold Resistance:0.5-0.6 ohms
Operating Resistance:1.75 ohms
(It shows similar through 1972)

For a 1974:
Part # RU-14 (dual ballast)
Cold Resistance:1.15-1.38 ohms
Operating Resistance:4.75-5.75 ohms At 25 Degrees C

So I gotta think the ballast change-over mandated in the Mopar conversion kit is significant??

 

[RJRENTON]

Thanks for the reply and yes, HH is always a great help in all things electrical - and that chart is well known,
of course - but it doesn't really help when it lists several different impendences for the same ECU, nor for
different coils with the same this or that - not to mention, there's no years or engine applications listed, either.
I always took that to mean you had a window of acceptable ballasts for those same units, since that's what
the chart indicated....not much help when you want to know what MOPAR actually sold in the conversion kits.

Yes, I'm making a big assumption that what Ma sold was correct out of the box here, but I'll go with it if I can
find out what the heck it was...
And by the way, the Mopar "performance electronic ignition conversion kits" used a single ballast and in the
instructions, it specifically says how to wire a car that had a dual ballast to it, that those were "unnecessary".
I've got a copy of the installation instructions for the old kits (well, the ones being made in the late 70's,
anyways) in PDF format that I could probably copy/paste into a large post on here if anyone would like
to see it.
Unfortunately, it does not specifically list individual kit components by part number (or by rating, in the case
of the ballast). I have been told by a couple folks who should know that the ballast in those kits was 0.8ohm
rated - it would just be nice to know for sure.

Another thing that interests me is the reference by more than one that we must use a coil made specifically
for electronic ignitions, when I just saw again that Ma didn't change coils from the 60's on to 1978??
Same coil, whether points or ECU eh?

As an aside, I've been playing around on the Standard Ignition website (great source of info since 1919!)
For my 1968 (standard points), it shows for a stock ballast:
Part # RU-4 (single ballast)
Cold Resistance:0.5-0.6 ohms
Operating Resistance:1.75 ohms
(It shows similar through 1972)

For a 1974:
Part # RU-14 (dual ballast)
Cold Resistance:1.15-1.38 ohms
Operating Resistance:4.75-5.75 ohms At 25 Degrees C

So I gotta think the ballast change-over mandated in the Mopar conversion kit is significant??

The ORIGIONAL ballast resistor was a positive temperature coefficient device. The purpose was to provide a VARIABLE resistance that increased as it got hot. This was done to allow for variable coil current; as the resistance increased, the coil primary current decreased slightly to reduce coil current (presumably in a points equipment car) to prolong their life by reduced arcing and in an ECU system, to reduce coil current and subsequently overhesting. Check out the FSM for a better description of the ballast resistor's function. This is totally independent of the ballast resistor's bypass circuit to provide full voltage to the coil when starting. This aspect MAY account for the numerous posted value. These resistors may or may not be positive temperature coefficient devices.
There are several additional factors involved, such as the coil's DC resistance and the inductive reactance which affects the rate (time) of the charging and subsequently the discharge rate when the spark is generated.
Just my opinion of course.
BOB RENTON

 

[Bee1971]

Standard RU12 Dual Ballast is 1.2 OHM + 5 OHM
My 71 Bee has a Dual Ballast Resistor wiring harness when I converted over many moons ago
I guess I wanted that factory look of electronic ignition

Standard UC12 Ignition Coil

And I just picked up these New Standard Made In The USA Old Stock Ignition Modules / ECUs

 

[Bee1971]

Factory Chrysler Dual Ballast Resistor

 

[Red63440]

So if I am making the correct assumption based on what has been posted I could cut the double connector off my ballast resistor harness and replace it with a single female spade connector which would eliminate my mess from, the PO and make sure contact was positive. The wires that are running to the double plug are split between one connector on the resistor so only half the signal is getting through depending on which side of the plug is connected.

 

[Red63440]

All that pretty white paint on your inner fender where you orange box is mounted is probably causing all of your woes. If that box doesn't have a less than .05 ohms from the case to neg post on the battery, it will get hot and open up until it cools down. Happens all the time. Paint is not a good ground. I hear guys whining about the orange box failing when more than likely was too much paint under the mounting screws.

That's original paint and that system has been on the car for several years. Part of the issue was a faulty connection, I thought that had been taken care of but with the pin on the double connector still involved it causes the plug to tilt to one side when hot....that will change tomorrow when its removed and replaced with a single plug containing all the wires on that left side. Not a great photo but it will give you the idea of what I am talking about.

 

[Bee1971]

So your still running into issues ?

Like six pack said check your ground also on your ECU

Anyways

Unplug your original factory blue wiring black connector from that female gray connector

Plug your black connector original blue wiring into this dual male spade on Ballast Resistor

Then just add a female connector to that ECU wire and

Your not messing up your factory wiring

Should bee available at any parts store