Which Ballast resistors do i need?

[Back N Black]

I have the new engine wiring harness from YearOne to up grade to electronic ignition. I also have the Mopar Performance ignition upgrade kit. The distributor kit has a 2 prong ballast resistor, but the new engine harness has a set up for 4 wires.
So, do i just buy a new ballast resistor with the 4 prong?  Also, the orange box has four prongs and the connector in the harness has five holes?

Here is a couple of pics of the resistor plugs.

[Back N Black]

 

[Chatt69chgr]

I bet Nacho is already typing his response on this.

I'am glad you have posed this question because I will be facing exactly the same thing at some point in the future.

[Rolling_Thunder]

just use a later model 4 prong resistor

[firefighter3931]

If i'm not mistaken the 4 prong ballist is used with a 5 wire harness that connects to the ECU. The dual prong is used when there are only 4 wires running to the box.

Switch over to MSD....problem solved. 


Ron

[Nacho-RT74]

4 prong ballast ( dual ballast ) are made to match with 5 pins modules... but works with 4 pin modules

2 prongs resistors ( single ballast ) are made to points ign and electronic modules with 4 pins modules. won't work on 5 pins modules

the pin on existing on 5 pins modules and deleted on 4 pin modules did get voltage from the secondarie resistance ( extra prongs ) on ballast. I guess to change the voltage or pulse coming from module  somehow to send to coil according to temperature. 4 pins modules doesn't need that extra voltage from exterior.

So, if you have a dual ballast wiring and 4 pins module you can simply plug and play with it using the stock dual ballast. Only diff is that I THINK ( I made a thread searching for info about that... will float on back ) there is not dual ballast with 1/4 ohm resistance on primary section like the single ballast HiPo available. I think minimun double ballast on primary resistance is 1/2 ohm.

the other chance if you WANT a 1/4 ohm resistance and if there is not dual ballast with that resistance, is simply plug the harness it on the correct side of plugs to the resistor,the problem is will look something weird.

The next solution to make it look better will be eliminate the extra wires to the resistor and change both resistor dual plugs to a couple of regular single plugs

wires to be eliminated is one of the single blue wires arriving to one of the plugs, and the bluegreenish wire with a red trace arriving to teh other plug, what is what would feed the deleted pin on 4 pins module.

Does look the plug getting two blue wires are both getting direct power from the internal splice so should it be the same wich blue wire you choose to cut ( be sure on that first anyway )... on stock wirings that plug just get one blue wire and then a jumper to the other prong on same plug.

I'm using the dual ballast I think as far I remember 1/2 ohm on primary resistance with my HiPo Mopar ign setup without problem ( chrome box and MP dist, with MSD blaster 2  coil  ). Will be interesting to check if I get a MAJOR change using a 1/4 ohm resistor

[Back N Black]

Thanks, for the info. I'm going to use the dual ballast resistor.

[71 Bee Man]

If i'm not mistaken the 4 prong ballist is used with a 5 wire harness that connects to the ECU. The dual prong is used when there are only 4 wires running to the box.

Switch over to MSD....problem solved. 


Ron

G'day guys,

hopefully I can get a quick reply from someone.....as we speak a mate of mine (some distance away) is having trouble with his 71 Charger 440. Car turns over - won't start. Got fuel and spark. i recommended checking the ignition ballast - can it simply be "shorted" by running a wire from one contact to another to see if she fires ?

Peter
Sydney, Australia.

[firefighter3931]

Peter, if it's got fuel and spark the problem most likely is something else. You could have him check voltage at the coil....it should have 8+ volts.

Yes, you can install a jumper wire to bypass the ballist resistor but this will burn the coil in short order.

Have him look at the spark color : dull orange means it's weak....it should be blueish-white. 



Ron

[71 Bee Man]

Peter, if it's got fuel and spark the problem most likely is something else. You could have him check voltage at the coil....it should have 8+ volts.

Yes, you can install a jumper wire to bypass the ballist resistor but this will burn the coil in short order.

Have him look at the spark color : dull orange means it's weak....it should be blueish-white. 



Ron

Hi Ron,

thanks very much for the reply. I'm going to try and head to his house tomorrow as it's really hard trying to fix something over the phone. There's no other big block Mopar guys around that we can call on and we're about the only ones I know of with 3rd Gens.

The other day he had the car running and then it just stopped all of a sudden. He now has it trying to kick over, but it won't start. He bought a new coil because he said the old one had a lot of oil seepage on it, but he also said the coil lead looks a bit ordinary, so tomorrow he's going to replace that also. He's no mechanic by any stretch so it's a bit hard. An auto electrician can't get there for a couple of days.

Someone else suggested the Electronic ignition.

Is it possible to have spark at the plugs, but the coil to be not working ? A nd if so, would this give the result of the engine turning but not firing ?

Peter

[FLG]

If you have spark at the plugs, the coil is working. But you are looking for a nice blue whiteish spark not yellow/red. If you have weak spark you need to then see if its a problem with the resistor, coil, cap..ect. With a car running you should be able to pull off a boot from the cap and pull the wire away just enough and you will still see the spark jump from the end of the wire into the cap (kinda like a mini lightning bolt). Though ive been shocked plenty of times doing that so i dont really recommend it.

[71 Bee Man]

If you have spark at the plugs, the coil is working. But you are looking for a nice blue whiteish spark not yellow/red. If you have weak spark you need to then see if its a problem with the resistor, coil, cap..ect. With a car running you should be able to pull off a boot from the cap and pull the wire away just enough and you will still see the spark jump from the end of the wire into the cap (kinda like a mini lightning bolt). Though ive been shocked plenty of times doing that so i dont really recommend it.

OK guys......for those of you that might be interested......



IT WAS THE COIL LEAD.

[Nacho-RT74]

Thanks, for the info. I'm going to use the dual ballast resistor.

yeah that will be fine... just that the secondary resistance will be like an ornament LOL, won't it be really working. Thats how mine is working.

try to find a dual resistor with .5 ohms on primary resistance for max performance on this setup... there are another ones with 1.5 ohms.