Duraspark Module Gets Hot, Quits

Fellow Jeepers,

I have installed the ignition upgrade on my 304 V8 using the duraspark module with the 84 ford coil and the cap, rotor and extension. The problem I am running into is the ignition module gets hot and quits in the middle of a trail ride. I have a warranteed module but I am tired of breaking down in the middle of a trail ride. I have a highly modified 74 trail jeep and lead most of my club rides. Does anyone have any ideas. Thank you for your time.

 

Does it have a ballast resistor? Many vehicles used a resistive wire to drop the voltage rather than a discrete ballast resistor.

This schematic http://www.buildyour4x4.com/BY-Tech/TFI-Schematic01.bmp shows a ballast resistor between the coil and the module. Even though the module uses 12V, it still has to sink the coil voltage through some silicon to ground in order to make the spark. If you don't have a ballast resistor to the coil, that could make the module hot (depending on how the module is designed).

Another possibility is your regulator is broken and the alternator voltage is too high. The module would likely be the first component to fail in that case.

<edit> another idea - make sure that your ground is good. If you are grounding the module to the fender, that may not be a quality ground. Check the resistance between your ground connection and the battery, and/or run an extra ground wire to a known good ground, like the battery cable connection on the engine block.

 

Yes, I put the ballast resistor that I made from another website.....I am an electronics tech and I know the resistor is working. According to the article you can connect the power from the ignition straight to it. I did that the first time. Now I have the ballast resistor and it still has same problem. Also the coil will take the power without ballast resistor. According to the article this makes it better than a GM HEI distributor. Stock CJ ignition is weak.

 

I don't have the start bypass in the circuit.

 

Yeah, even if the coil can take the increased voltage, there's a switch in the module that grounds the coil and collapses the magnetic field. Any semiconductor switch will generate some heat proportional to the barrier potential and current it's sinking. Maybe not significant between 8 and 12V.

 

Also, I was wrong about my wiring compared to the diagram. My power wire to the module come from the ignition post on the solenoid which gets its power via the ignition switch. That red wire on the ignition module should have power on it all the time right?

 

As I interpret this, The red wire connects to 12V (battery +) when the IS is at run position. The white wire floats at run, and the ballast resistor is in series with the coil field. When starting, the red wire is connected through the ballast resistor to 12V, the white wire connects directly to 12V, and the ballast resistor is bypassed

 

yes....so what can I do to stop my problem. The only other thing I know for sure is they say not to use wire core spark plug wires with this set up. I use spiral wound core wires. I have an extra set of wires and will change them out. One more thing. How do I get my jeep picture on my postings?

 

Sorry if I have confused you. The ignition module is heating up so much it melts the backing off of it. Once it cools off I can drive it out, but now I have an extra module.
So what do you think I should do?

 

Maybe an internal short?

 

I installed the new module and will try it again this weekend.....thank you for your help.....

 

The resistors in place of a ballast resistor are most likely the problem. Not only does the ballast drop the voltage it's resistance will increase as the current and heat increase. This is a design to keep the duraspark module from overheating. Ballasts are cheaper than replacing duraspark modules so I would invest in one of those. Also for note, the ballast for a late 70's dodge drops both coil and ignition box voltage to 8 and 12 respectively. Good if running a high output alternator.

 

If this is the module I'm thinking of, it's held right to the dist housing by a couple screws? (If not, disregard the rest of this post) If it is the one I'm thinking of, the backside of it needs to be greased up really good with some dielectric grease. If it's not, it will get really hot.

 

No, the Ford Duraspark module sits on the fender. The GM HEI module is in the distributor.

 

The ballast resistor I installed is a homemade deal I found on the internet. It consists of 4 (specific part # I can't remember) diodes soldered together. My jeep did not have a ballast resistor to begin with and when I installed the fiberglass tub I installed a new wiring harness. I also installed the ignition upgrade at same time as the tub and harness.

 

I just read the ignition upgrade article again. I have the duraspark module and the TFI coil. Article says both will take full 12 volt signal. Go to www.ifsa.org/tech/electrical/ignitionupgrade.shtml

 

my mistake www.ifsa.org/tech/electrical/ignitionupgrade.shtml

 

the link above does not work.....go to Google, type in amc ignition upgrade, it will take you directly to article I used to do my ignition system

 

IFSJA ...don't leave out the most important letter!

 

I have been away for the weekend.....Anyone have any ideas....I will try the Dodge ballast resistor on the module......The coil hasn't failed....thank you for your time