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Why would ballast get hot and stall car?

mquinn66

mquinn66

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My car keeps stalling after it has warmed up. The ballast gets hot so if i swap it it starts right back up and runs until it gets hot again. It ran fine in the heat of the summer why would it be an issue now? Could it be the voltage regulator? Or a bad coil? Both are new. I am running an orange box and msd blaster coil. Thanks for any advise you may have.
 
Ballast resistors get warm normally. I'd just change the ballast, or check it's ohm reading hot and cold, is shouldn't change much, or see if it shows open immediately upon stalling. I'd suspect the coil next. There was a bad run of Orange Boxes, and lately they're using fake transistors and crap innards.

Edit:
- Good advice below

- Everyone should buy a small multimeter at Home Depot or hardware store and learn how to use it. They're not expensive. Don't guess at electrical - diagnose.
 
Last edited:
This issue has caused many threads and is usually caused by people repainting their engine compartment and not cleaning off enough paint under the orange box to give it a proper ground. If no good ground is provided, (less than .5 ohms) the control box will get hot and open the circuit until it cools down. Everyone wants to replace parts when all it was is a bad ground. If you don't have a digital meter, get one and check the resistance between the orange box case and neg post on the battery. If it is more than .5 ohms, scrape of some paint and try it again. (First order of business before replacing ballast resistor or coil)
 
As far as a ignition box goes, I like the aftermarket units over the orange box. The Chrysler Chrome box is good but I’m not sure if there made or available anymore. So, step up to a FBO box from Don @ 4secondsflat.com or a Revenator. Mancini racing also has boxes painted Orange that are not a Chrysler box. There better and more reliable. A basic box from the parts store has proven more reliable than the Chrysler Orange.

Areyou sure this is ignition related and not carb?
 
it could be the coil,if you have a spare one change it and see if that solves your problem.
 
Demonic said:
Ballast resistors get warm normally. I'd just change the ballast, or check it's ohm reading hot and cold, is shouldn't change much, or see if it shows open immediately upon stalling. I'd suspect the coil next. There was a bad run of Orange Boxes, and lately they're using fake transistors and crap innards.

Edit:
- Good advice below

- Everyone should buy a small multimeter at Home Depot or hardware store and learn how to use it. They're not expensive. Don't guess at electrical - diagnose.
Click to expand...
I had one of the bad orange boxes recently. I put it on and it ran fine but I think I burned up two coils and had constant starting issues. I ended up selling that car however the guy that bought it told me he replaced the orange box. Now it runs and starts perfect
 
I like to put Star washers under every part and screw especially on the firewall.
It bites through the paint and provides a neat positive electrical connection. I
like stainless steel because they're harder and they don't rust.
 
zyzzyx said:
I like to put Star washers under every part and screw especially on the firewall.
It bites through the paint and provides a neat positive electrical connection. I
like stainless steel because they're harder and they don't rust.
Click to expand...
I agree. I also run a #12 wire from the control box to the motor ground strap for piece of mind.
 
Are you using the resistor MSD recommends with their coil?
They (used to) include a .75 ohm resistor with that coil...about half the ohm value of the stock one, but I've heard they no longer include it. Too high resistance for the coil is not good.

Honestly my bet is on the coil. Sounds like you've had it at least a couple of months which is plenty of time for a Blaster to crap the bed... I've personally had nothing but failures with MSD coils. FWIW the MSD coils I used all ran very hot--like over 200 hot--I now use a Pertronix Flamethrower with FBO box and no resistor, as directed, and that coil never gets over 150.
 
For a Mopar electronic ignition system using an "orange box" the box is designed for use with a stock coil and series ballast resistor. A stock coil primary resistance should be 1.6-1.8 Ohms at 70-80* F. The ballast resistor for a stock coil should be a nominal 1 .0 ohms as measured cold, that value, as measured may vary slightly, but should be darn close. Improper resistance of the coil and/or ballast resistor could cause problems. And yes, a good ground to the orange box case is important.
 
Thanks you all for your help on this issue. I made my ballast connections tighter, they were kinda loose. I also checked the box ground and added a ground to the firewall strap. Im not 100% convinced its fixed yet but didnt have a problem today for the short time i ran it. If it comes back my next step is testing the ballast and coil. Thanks again.
 
Sounds like you got it solved. Grounding problems are the biggest electrical problems we have with our old crusty rusty stuff. People upgrade to the electronic ignition and don't get a sufficient ground on the orange box. Then complain that they are junk. I have 3 vehicles with the orange box and have never had a failure since I learned about the grounding issue.
 
I use the Mancini orange boxes and give the mounting bolt holes a good sanding with rough sandpaper. The SS star washers is a good idea also. I also find the Mancini boxes to be more reliable.
 
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