Ballast Resistor Problem

[RAM318]

ABOUT 6 MONTHS AGO I PULLED THE COMPUTER AND FUEL INJECTION OFF MY 88 318 RAM AND REPLACED IT WITH A PERFORMER INTAKE AND CARB. AND A CHRYSLER PERFORMANCE DISTRIBUTOR ,COIL AND ORANGE ECU. NO PROBLEMS FOR 6 MONTHS BUT NOW ALL OF A SUDDEN SOMETIMES WHEN I GO TO CRANK IT ALL IT WILL DO IS SPIN THE MOTOR. THE FIRST TIME THIS HAPPENED I CHANGED THE BALLAST RESISTOR AND IT CRANKED RIGHT UP . WORKED FOR ABOUT A WEEK THEN SAME THING, CHANGED RESISTOR AGAIN CRANKED UP BUT RESISTOR STARTED SMOKING. CHECKED COIL, POWER,CONNECTIONS AND ANYTHING ELSE ANYONE WOULD SUGGEST.PUT ANOTHER RESISTOR IN ,CRANKED RIGHT UP BUT RESISTOR SMOKED AGAIN BUT IT STILL CRANKED UP. WHATS GOING ON????????

[72Challenger]

You left out the most likely problem - wiring. Check for a short if you're frying the resistor.

[dschumers]

I've had the same problem with my Valiant twice. The first time it was burning out the resistor, and I had the wrong type of coil on it. The second time it was because the old stock coil I had stuck on it to replace the first one went bad. It acted just how you described.

[warlockpowerwagon]

Actually when trying to start the engine, the ballast resistor is bypassed using the S2 (key in start position) cuircuit, on the wiring diagrams that I have checked. I have been told otherwise but cannot find proof. The S1 (key in run position) cuircuit passes through the ballast resistor after the engine has started. The diagrams show the S2 cuircuit going to the resistor, but if you will notice, does not pass through the resistor but branches off. The reason for this is so all the power can be used to fire the ignition and starter on start up, which is also why all the accesories are also not working when the key is in the start position (S2 cuircuit). When the ballast resistor goes bad, the engine will start but not stay running when the key is released to the run position.
You could check out BALLAST RESISTOR WIRING at http://members.nbci.com/dustermocar/ballast.htm
Or you could look at CHRYSLER ELECTRONIC IGNITION at http://www.fourforty.com/techstuff/ignition.html although old, it also lists some troubleshooting.
Or you could look at 4 PIN RESISTOR WIRING at http://members.nbci.com/dustermocar/techpage.htm
Or check out MP CONVERSION DIAGRAM at http://members.nbci.com/dustermocar/techpage.htm
So what I.m really trying to say is that if the engine does not start, it is not the ballast resistor, but some other problem. (which may be causing the failure)
I would sooner think that maybe you haven't got a good ground to the ECU and the firewall. You can check the diagrams and if you check pin 5 on the ECU continuity, it should show positive. (direct link to ground) If it does not show continuity then you have got to ground the ECU better.
Are you using the correct resistor for the coiul and your system?
Sorry this is so long, and sorry for being so confusing.

[GTXMONTE]

My LIL RED truck had the same symptoms once before and it turned out to be a bad ignition switch(electrical part of the switch down on the column). Mine would wind and wind, and crank if you backed of the key just a touch. The contacts in the switch were worn from years of cranking. Most all the ballast resistors will smoke the first time they heat up.

Monte Smith

[451Mopar]

Ram318,
You could have a few different problems.
It is somewhat common for a new Ballast resistor to smoke a bit when it is first used, but it should not burn out.
If you are burning out ballast resistors, you may have a short in the ignition coil.
If you are having a "hard start" problem where the engine won't fire up while cranking it may be a wiring or ignition switch problem problem, but if everything checks out OK, and the problem happens usually only when the engine is hot or the engine tries to fire only when releasing the key then you mah have a bad battery cable (specifically the ground wire) causing a large voltage drop to the ignition when cranking the engine. Because the starter draws large amounts of current, any resistance in the battery cables creates a large voltage drop (Voltage=Current X Resistance.)
Example, Starter draws 75 to 100 Amps, and the ground battery cable has 0.050 (50-milliOhm) resistance, you would drop 3.75 volts to 5.00 volts accross the ground wire, this would reduce the voltage to the ignition system by an equal amount.
Good battery cables and a good body ground wire from the battery post to the body of the car really helps this problem.

[RAM318]

THANKS FOR ALL THE SUGGESTIONS.I THINK I MAY HAVE HAD TWO PROBLEMS. MY COIL WAS BAD FOR SURE BUT I ALSO REPLACED THE IGNITION SWITCH UNDER THE DASH ON THE STEERING COLUMN. ITS BEEN ABOUT TWO WEEKS AND I HAVENT HAD ANY MORE TROUBLE WITH IT.THANKS AGAIN. RAM318