Main Menu

Starting issue, maybe ballast resistor related?

Started by JH27N0B, October 23, 2022, 06:23:25 PM

Previous topic Next topic

0 Members and 2 Guests are viewing this topic.

JH27N0B

This problem is on my '78 B body not one of my Es but the same principles should apply.
It's a Magnum with a 360 4 barrel.  Lean Burn long gone.  Edelbrock 4 barrel, otherwise relatively stock but I'm not sure what, if any liberties were taken with the ignition system.
On starting up, it will often turn over but not even hiccup, until turning the key back after giving up, it might burp for an instant as the key goes back to "off".
After a couple or 3 or 4 tries it will usually fire up.  Sometimes even fire on the first try.
Local friends at cruises gave me some ideas.  First I installed a new Mopar orange box ECU.
No luck.
Several suggestions on the 4 prong ballast resistor being suspect.  One evening at a cruise the car wouldn't start at all.  A buddy lent me a new ballast resistor, it started right up!  Unplugged it, plugged back in mine, started right up. Drove home and ordered a new one.
Installed it. Same deal with intermittent firing up.
I found if it didn't start after 3 or 4 tries, I can unplug the ballast resistor, and plug back in, and the car then fires up at the first turn of the key.
I'm a electrical idiot, don't even own a voltmeter.  I took it to my friends house who is good with electrical trouble shooting a few weeks ago, he spent some time cleaning the contacts in the plug, and put some dielectric grease on the ballast tabs.
Fired right up and seemed good multiple times. I headed off to a cruise and a couple hours later when I went to leave, took a couple tries before it fired.
I'm out of ideas or parts to throw at this.  :pullinghair: Anybody ever encountered anything like this with a Mopar ignition system before?

1970A-66Challenger

I had a similar intermittent starting issue, ended up being the pickup in the distributor.

JH27N0B

Interesting.  Was this with an electronic ignition?  Was it the reluctor or is the pickup something different?
I'm still suspicious of something with the plugs or wiring to the ballast resistor.  So far every time if it doesn't start after 4 or 5 times, I unplug one connector on the ballast , plug back in, turn key, it fires.
I'm concerned this trick will work, until it doesn't. Then I'll be stranded somewhere!


1970A-66Challenger

This was with a modern mopar electronic ignition conversion setup. The pickup is essentially a magnetic switch that the reluctor triggers as it rotates. The issue was not the reluctor/pickup gap, but an issue with the pickup itself. You can measure the pickup resistance by unplugging the distributor wiring connector and measuring across the two leads going to the distributor. I don't recall what the correct ohm range should be but I'm sure it's easily found on the internet. Sometimes my pickup would test good, other times bad.

JH27N0B


DeathProofCuda

Quote from: JH27N0B on October 23, 2022, 06:59:35 PM
Interesting.  Was this with an electronic ignition?  Was it the reluctor or is the pickup something different?
I'm still suspicious of something with the plugs or wiring to the ballast resistor.  So far every time if it doesn't start after 4 or 5 times, I unplug one connector on the ballast , plug back in, turn key, it fires.
I'm concerned this trick will work, until it doesn't. Then I'll be stranded somewhere!

Which connector on the ballast resister are you unplugging and reconnecting? 

Keep in mind that your car doesn't need the ballast resistor to "start", it only needs it to "run".  When you have your key turned to the "start" position you are bypassing the ballast resistor.  The ballast resistor is only in line when the key is released to the "run" position.  That is why the classic ballast resistor failure symptoms are a car that starts and then immediately dies when the key is released to "run".

If unplugging and then reconnecting your ballast resistor wire really is your fix, then I'd suspect a loose connection in your wiring harness.  Maybe in the connector where the blue and brown wire connect to the ballast resistor.

I'll also throw in my two cents to say that anyone that is messing around with old cars should have a multimeter and figure out how to use it.

MoparLeo

#6
Since it seems that unplugging the ballast resistor and even changing it has the same effect. Maybe check the wires/plug that you are disconnecting.
Next time it doesn't start, have someone inside the car cranking the engine while you just wiggle the ballast wires. If it starts, the problem is a broken connection in the wire some where.
This is where a volt/ohm meter comes in handy to check resistance and continuity. :tool:
moparleo@hotmail.com  For professionally rebuilt door hinges...


Burdar

QuoteKeep in mind that your car doesn't need the ballast resistor to "start", it only needs it to "run".  When you have your key turned to the "start" position you are bypassing the ballast resistor.  The ballast resistor is only in line when the key is released to the "run" position.  That is why the classic ballast resistor failure symptoms are a car that starts and then immediately dies when the key is released to "run".

Take note of this because he is absolutely correct.  Whenever someone says their car won't start, most people just shout out BALLAST RESISTOR.  Not true. 

blue wire out of ignition switch = ignition power during "run"
brown wire out of ignition switch = ignition power during "start"
yellow wire out of ignition switch = to starter relay

You need to start testing wires and connections.  Start under the steering column and test all the connections on the brown wire all the way to the ballast as someone holds the key to "start".  Move the wiring harness around and look for a loose connection.  Then do the same thing with the blue wire when the key is in the "run" position.  If you remove the yellow wire from the starter relay, that will disable the starter so it won't turn over while you test.

DeathProofCuda

Quote from: MoparLeo on October 23, 2022, 11:42:38 PM
Next time it doesn't start, have someone inside the cat cranking the engine while you just wiggle the ballast wires. If it starts the b problem is a broken connection in the wire some where. This is where a volt/ohm meter comes in handy to check resistance and continuity.

Great suggestion.  :cheers:

DeathProofCuda

Quote from: Burdar on October 24, 2022, 09:12:15 AM
QuoteWhenever someone says their car won't start, most people just shout out BALLAST RESISTOR.  Not true. 

:perfect10:

JH27N0B

I had a ballast resistor go bad on one of my Challengers decades ago, so have experienced the engine starting then shutting down immediately as you rotate the key back the run position problem.
I've been carrying a spare one in my first aid kit in my Challenger convertible's trunk for a long time now and fortunately haven't had to use it yet.
We had a little father's day gathering at a restaurant in June and the car wouldn't start when I went to leave. Nice having a half dozen Mopar guys rush over and stand around shoulder to shoulder under your hood helping to try to get your car started!
After screwing around for a bit mostly focusing on the carb, the car started.  As I shifted into drive, one of their sons, who is a real sharp CJDR tech, said you might want to check your ballast resistor.  He's far from some usual tech of this era who wouldn't have even heard of a ballast resistor unless there was a code for it on a scanner, his dad has a Challenger drag car, a mild custom GTX and a 50s Imperial, so he's probably been working on vintage Mopars with his dad since he was old enough to grip a wrench.  But I still wrote off his advice, as the experience I was having was the opposite of what I knew as a ballast resistor failure. No firing when starter is engaged, but burping briefly as the key passed through the run position on the way to going to the off position.
Then in July while having the problem at a cruise, a friend who is a retired fleet mechanic who owns a 70 Superbee with a hemi in it, (its a V code but its had a hemi in it since he got it in the mid 70s), and a 67 vette, said he was suspicious of the ballast resistor and brought over a spare from his car's first aid kit, and we plugged it in and the car fired up.  That was the time I then unplugged it, plugged back into mine (those things get hot!) and the car started first try with the ballast resistor after not starting with it 10 minutes earlier.
So I had to wonder if there was a little more to ballast resistors than I'd thought, at least something more to 4 prongs than the 2 prong ones I've always had on all my Challengers.
I've looked online trying to find the difference between 2 and 4 prong ballast resistors, and get conflicting info.  I've seen it said one circuit in a 4 prong is start, and the other is run.  Others say that after 5 pin ECUs for electronic ignitions were changed to 4 pin ECUs, and internal resistor was incorporated into the ECU and the second circuit in the ballast resistor is now a path to no where. Another friends advice to replace the ECU tied into that, he thought I must have had a 5 pin, but when I unscrewed the retainer screw and unplugged my ECU later in my garage, I found that my car already had a 4 pin ECU on it. 
So it's all very confusing!
At any rate, I have been disconnecting the connector on the drivers side circled in the picture, and plugging back in, as my hack to start the car when it does its won't start game.
An unrelated question, my fleet mechanic friend was really curious what the second voltage regulator looking component is on my firewall (also circled).  He looked at service manuals and online car parts catalogs later and still couldn't nail down for certain what it is.  He thought maybe something tied in with the lean burn system.  Anyone know?


chargerdon

On my 74 Challenger with stock electronic ignition, i ran into a somewhat similar problem.   Often, when cranking the car with the key it would not start, but, sometimes would "catch" when you released the key to the run position after attempting to start.   I even came to realize that i could start the car by putting the key in to the "run" position and then force the starter to crank by a jumper wire at the starter relay.   In other words the car would not start with the start position of the key, but would on run if you jumper the starter relay.

I would do continuity checks for the start circuit and get continuity however it wasn't putting enough "voltage or current" with the start circuit.   The ECU needs at least 9 volts or it wont detect the reluctor and wont fire the coil.   Turns out the wires were not making the best connection going thru the firewall connector for the start circuit.   Took it out of the bulk header connector on the dash side, cleaned it on the dash side, put it back in, and then cleaned the wire going into it on engine side and problem solved.   

MoparLeo

#12
The dual ballast resistor had 2 different jobs. One side controlled current to the coil, the other side controlled current to the ECU.
The original single ballast was for the older point type ignition so it was for the coil only.
The Orange box had an internal resistor, so it didn't need the dual ballast.
Running the engine with the ballast bypassed will give you some improved spark from the ECU at the expense of a shorter coil and ECU life.
moparleo@hotmail.com  For professionally rebuilt door hinges...

chargerdon

Quote from: JH27N0B on October 24, 2022, 12:08:57 PM
I had a ballast resistor go bad on one of my Challengers decades ago, so have experienced the engine starting then shutting down immediately as you rotate the key back the run position problem.
I've been carrying a spare one in my first aid kit in my Challenger convertible's trunk for a long time now and fortunately haven't had to use it yet.
We had a little father's day gathering at a restaurant in June and the car wouldn't start when I went to leave. Nice having a half dozen Mopar guys rush over and stand around shoulder to shoulder under your hood helping to try to get your car started!
After screwing around for a bit mostly focusing on the carb, the car started.  As I shifted into drive, one of their sons, who is a real sharp CJDR tech, said you might want to check your ballast resistor.  He's far from some usual tech of this era who wouldn't have even heard of a ballast resistor unless there was a code for it on a scanner, his dad has a Challenger drag car, a mild custom GTX and a 50s Imperial, so he's probably been working on vintage Mopars with his dad since he was old enough to grip a wrench.  But I still wrote off his advice, as the experience I was having was the opposite of what I knew as a ballast resistor failure. No firing when starter is engaged, but burping briefly as the key passed through the run position on the way to going to the off position.
Then in July while having the problem at a cruise, a friend who is a retired fleet mechanic who owns a 70 Superbee with a hemi in it, (its a V code but its had a hemi in it since he got it in the mid 70s), and a 67 vette, said he was suspicious of the ballast resistor and brought over a spare from his car's first aid kit, and we plugged it in and the car fired up.  That was the time I then unplugged it, plugged back into mine (those things get hot!) and the car started first try with the ballast resistor after not starting with it 10 minutes earlier.
So I had to wonder if there was a little more to ballast resistors than I'd thought, at least something more to 4 prongs than the 2 prong ones I've always had on all my Challengers.
I've looked online trying to find the difference between 2 and 4 prong ballast resistors, and get conflicting info.  I've seen it said one circuit in a 4 prong is start, and the other is run.  Others say that after 5 pin ECUs for electronic ignitions were changed to 4 pin ECUs, and internal resistor was incorporated into the ECU and the second circuit in the ballast resistor is now a path to no where. Another friends advice to replace the ECU tied into that, he thought I must have had a 5 pin, but when I unscrewed the retainer screw and unplugged my ECU later in my garage, I found that my car already had a 4 pin ECU on it. 
So it's all very confusing!
At any rate, I have been disconnecting the connector on the drivers side circled in the picture, and plugging back in, as my hack to start the car when it does its won't start game.
An unrelated question, my fleet mechanic friend was really curious what the second voltage regulator looking component is on my firewall (also circled).  He looked at service manuals and online car parts catalogs later and still couldn't nail down for certain what it is.  He thought maybe something tied in with the lean burn system.  Anyone know?

First, the "second" ballast resistor on the wiper motor is for the wiper motor only and has nothing to do with the ignition system.
Second, Early versions of Mopar Electronic ignition system was a 5 Pin ECU and required the 4 post ballast resistor... one side for the coil, and the other side to reduce the voltage to the ECU.    In later years the ECU itself had a resistor built in so that the 4 post ballast resistor isn't needed...only two post.     However, IF you have the older system, you can replace it with a 4 pin ECU and it definitely will work with the 4 post ballast resistor.  In fact finding 5 pin ECU's are difficult to even find, but, there is no reason to do so as the 4 pin will work.   

JH27N0B

It wasn't the ballast resistor on the wiper motor we couldn't figure out what it's for.  It is the second voltage regulator-like part on the firewall to the left of the voltage regulator we can't identify.
My "snip" function only has red, blue and black pens so it's hard to circle it in a way that jumps out on the picture, but it is the dark orange part between the ECU and the black voltage regulator.
The mention of the inadequate voltage to the ECU had me wondering about something.  There is the flaw in our electrical systems where connections go bad at the bulkhead pass through, and can overheat and can even cause a fire.  I seem to recall there is a bad design issue involving the alternator gage and that can cause starting issues, or is my memory flawed?
The one gage that isn't working in this car is the that one, the needle is on the low side of the center mark and never budges.  Trying to troubleshoot that or add an aftermarket gage is on my list as I want a heads up if my alternator fails!
Is there any chance that could be tied in with my starting issue?