I'm a newbie to the group, looking forward to reading all the discussions! Anyway I own a '75 Valiant Custom 4 door with the 225 cid slant six and torqueflite auto tranny. The engine is in great shape with only 97,000 miles. The carburetor will need work soon as it idles roughly from time to time. The biggie I'm concerned about however, is that I have had premature failures of the electronic ignition unit (EIU) and ignition coil. I'm going to list the incidents I had with the car:

May '05: Car broke down, wouldn't crank at all. Ignition relay and EIU failed.

August '05: Car broke down again, cranked but wouldnt start. Replaced the EIU with a spare, but it failed within a second. Turned out the ignition coil was the culprit.

January '07: Car broke down while moving to S Calif from N Calif, it was the alternator and voltage regulator. Had a shop fix it, then after reaching my new city, the car broke down. It started but stalled immediately when turned from start. Had to have the starter cranking to make it to my place but wasn't too far. Thought it was the ballast resistor but replacing it didn't help. Turned out the ignition coil was bad so replaced it. Worked fine for a while.

July '07: After a day on the road in the LA area, I was driving back home. On I-5 at about 65 mph I changed lanes and accelerated, the car stumpled three times and nearly broke down. After that happened, the engine felt underpowered and it felt like it would stall if the engine got slow enough. I floored on the way back to ventura county and made it back to the city where I live. Took the exit and while I stopped at the right light the poor mopar broke down. Had to have it towed home. I replaced the ignition module, the car started but stalled when placed into reverse or drive. Replaced the ignition coil and it finally ran again.

You can see that I have gone through three EIUs and ignition coils. Today the car chose to act up again, I smelled something burning like the red end of matches but it was only a minute. Drove it back home. On inspection both the ballast resistor and EIU got kinda hot to the touch, hotter than the sheet metal around them. Is this normal? Sorry for the long post but I really need to fix this, as there is something wrong that is triggering the numberous coil and EIU failures. Please help, thanks!

Dave

Whats the condition of your wiring? are their fuses in line? they should blow because if something heating up that badly I would think it's shorting out somewhere.

What are the condition of these components? junkyard fresh offer no guarantee that replacing them will fix it. although I'm not saying you should go buy new with the problems your having.

I will check the wiring as soon as I am able, thanks. Where would a short that affects the ignition components arise? In the ignition circuit or elsewhere? Also, are ballast resistors and EIUs supposed to generate heat? Thanks, Dave

i'm not so sure on the heat issue but i'd trace along any wire that connect to these components and see if there are breaks in them, check your ground also could be as simple as taking the ground off and cleaning it with emery cloth and you could be good. electrical is stupid like that. umm but yeah check your wiring out it could just be as simple as two wires are cracked and touching together.

Ballast resistors and ignition ECMs do get hot in normal use. The ballast resistor can get hot enough to burn you (though not seriously); the ECM can run "very warm" but should not be warmer than that. What are you buying for replacement coils and ECMs?

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Do you have a volt meter installed? If so what is it showing? If not, check to see how much voltage is at the battery when it's running. Sometimes the voltage regulator can be defective and put out some serious voltage, enough to get the wires hot....and roast a few things which leads to what you have described. I had it happen once and had to replace some cooked wires. Bottom line replace the voltage regulator before it eats your battery and burns up the alternator, pending if you find the voltage is too high (over 13.5 volts).

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Thanks guys for the tips. I got my multimeter out and tested the resistance of the ballast resistor and the voltage reaching the ignition coil as well as the charging voltage at the battery. Here are the results:

Ballast resistor: around 1.3 ohms for primary resistor, 5.6 ohms for auxiliary resistor

Voltage at positive terminal of coil: 9.8 volts while engine is running

Voltage at battery while engine is running: 14.5 volts, even when headlights are lit the voltage didn't drop at all.

Oh by the way the last two times when I bought replacement coils and EIUs, they are the Duralast brands sold at AutoZone. Not sure if it is cuz they are bad quality cuz I had the same problems with other brands of parts, including an MSD coil that came with the car when I got it.
What do you guys think? Any help is appreciated, thanks

Ah...fixing the problem for good could be simply a matter of buying quality parts. "Duralast" = trash. Start buying name-brand ignition parts (Standard/Bluestreak, NAPA Echlin) and perhaps your troubles will stop.

14.5v is kind of on the high side for line voltage with the engine running at California daytime temperatures, and suggests the line voltage could be spiking even higher under transient and/or colder conditions. Guessing the "new" alternator and voltage regulator are also "Duralast"?

Bad-quality parts are significantly responsible for the "common knowledge" that old cars are unreliable because they're always breaking down.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

I agree that the voltage is pretty high causing the burn out/failure of the components. For reference my voltage across the battery while running is 13.54, and voltage at the coil is 6 volts @ a 650 rpm idle. Ballast resistor ohm readings are similar. Looks like your voltage regulator is letting too much through. Try to find a NAPA and get some basic and stable parts.

I am surprised your battery isn't covered in white corrosion from boiling over due to over charging....

I bought my regulator from Summit, under the MOPAR section. It is pretty accurate. I have tried other brands and they usually over charge or under charging the system resulting in the headlights to be on the dim side.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

A coil shorting internally can still spark, but quickly fry the ignition module, but getting 3 failures in a row is probably a record.

May I suggest you carefully check the grounding of your voltage regulator and the line leading to it from the alternator? An intermittant open in the former or short in the latter may be hard to find, but could fry a module. Coils usually will take a lot of abuse, though. Good Luck.

have to agree on the good components. I've got an 84 ramcharger that fails less then some of my buddies new cars because they use crappy components. the only time I've had to replace anything is regular maintainence. so yeah buy the good quality and you'll win in the long run.