why a 4 prong balast?

Posted By: Mr.Yuck

why a 4 prong balast? - 09/19/08 01:39 PM

Just oredered my engine harness for my 70 Charger. it has electronic ingniton, guy said something about the harness has been modified and I'll need a 4 prong balast. I have some at home but I've never used one and the MP elect ing distrib kit comes w/ a 2 prong...any reason why?

Posted By: 540challenger

Re: why a 4 prong balast? - 09/19/08 01:43 PM

Quote:

Just oredered my engine harness for my 70 Charger. it has electronic ingniton, guy said something about the harness has been modified and I'll need a 4 prong balast. I have some at home but I've never used one and the MP elect ing distrib kit comes w/ a 2 prong...any reason why?

Stock mopar electronic ingn came with a 4 prong. The modified harness has the connentors for the 4 prong installed. As it would "IF" the factory would of had made it.

If you order a stock engine harness for the points set up then you can just use the 2 prong as just have been to convert over with the kit mopar and others sell.

Posted By: Mr.Yuck

Re: why a 4 prong balast? - 09/19/08 01:45 PM

Yeah I was thinking about that as the distrib kit has a harness in it. I got the modified one because it's ready to go. So I guess I'll need to use one of those bulky 4 prong units.

Posted By: 540challenger

Re: why a 4 prong balast? - 09/19/08 01:56 PM

Quote:

Yeah I was thinking about that as the distrib kit has a harness in it. I got the modified one because it's ready to go. So I guess I'll need to use one of those bulky 4 prong units.

Yup get the 4 rpong and you are set.

Posted By: MoparforLife

Re: why a 4 prong balast? - 09/19/08 02:02 PM

Not modified just designed after the first years of the Mopar electronic ignition where one side is the start circuit and the other side of the ballast is the run circuit. The later 2 prone ballast has only the run circuit.

Posted By: 1fastrunner

Re: why a 4 prong balast? - 09/19/08 09:33 PM

I have the 4 prong hookup on my harness, but I use a 2 prong ballast and only plug in 2 of the prongs.
Jim

Posted By: Supercuda

Re: why a 4 prong balast? - 09/19/08 09:39 PM

Quote:

Not modified just designed after the first years of the Mopar electronic ignition where one side is the start circuit and the other side of the ballast is the run circuit. The later 2 prone ballast has only the run circuit.

Ah, no.

The four prong setup used one side for the coil just like the two prong setup. The other side was used with the 5 prong ECU and was the biasing resistor for the power transistor.

The four prong ECU's didn't require an external biasing resistor. So if you have a 4 prong ECU you do NOT have to use the 4 prong ballast resistor.

Posted By: RapidRobert

Re: why a 4 prong balast? - 09/19/08 10:07 PM

Quote:

The other side was used with the 5 prong ECU and was the biasing resistor for the power transistor. The four prong ECU's didn't require an external biasing resistor. So if you have a 4 prong ECU you do NOT have to use the 4 prong ballast resistor.

To clarify for me (1)the 5 pin ECU's got reduced voltage thru this resistor during start and run? and (2) which resistor was to the ECU,the .5ohm or the 5 ohm? thank you for your time.

Posted By: Kevins493

Re: why a 4 prong balast? - 09/20/08 12:25 AM

Jeff,

We have a few of the 4 prong ballast resisitors if you need them. We put an orange box on the challenger and use a 2 prong resisitor (just leave the other two connectors hanging).

Posted By: Mr.Yuck

Re: why a 4 prong balast? - 09/20/08 01:11 AM

Thanks Kev and the rest of you..so do I use all 4 w/ the Mopar Perf elect dist kit?

Posted By: 383man

Re: why a 4 prong balast? - 09/20/08 01:19 AM

First if you use a 4 pin ECU box then you can use a 2 prong ballast. The .5 ohm ballast is to the coil and the 5 ohm was for the auxilary run circuit to the ECU that was ign run voltage thru the 5 ohm side to the ECU. This 5 ohm auxilary ign run (its not a start circuit as many think) is the circuit that is eliminated on the 4 pin ECU and you can just leave that side unhooked and use a 2 prong ballast with the 4 pin ECU. Ron

Posted By: RapidRobert

Re: why a 4 prong balast? - 09/20/08 03:16 AM

Thanks Ron. Got it.

Posted By: Mr.Yuck

Re: why a 4 prong balast? - 09/20/08 01:14 PM

So ron should I run the 2 or 4??? or does it really matter?

Posted By: 383man

Re: why a 4 prong balast? - 09/20/08 02:44 PM

If you have the 4 pin ECU then you only need to run the 2 prong ballast.

Ron

Posted By: GODSCOUNTRY340

Re: why a 4 prong balast? - 09/20/08 02:44 PM

It depends on your ECU. If you have the 4 peg ECU you only need the 2 prong ballast. If you have the 5 peg ECU you need the 4 prong ballast.

Posted By: Mr.Yuck

Re: why a 4 prong balast? - 09/20/08 03:16 PM

thanks guys, I'll check in a few.

Posted By: Supercuda

Re: why a 4 prong balast? - 09/21/08 08:38 PM

Quote:

It depends on your ECU. If you have the 4 peg ECU you only need the 2 prong ballast. If you have the 5 peg ECU you need the 4 prong ballast.

Not necessarily. The 4 prong ECu superceded the 5 prong setup and it a plug-n-play replacement. However, the average DIY'er would grump that his new ECU only had 4 pins and not 5 like his original and therefore must be wrong. So there was a dummy fifth pin put in alot of them to satisfy customer demand.

I doubt you can buy a non-NOS 5 pin ECU that actually needs the four prong ballast anymore. You might find a 5 pin unit, but I'll bet, if I was a betting man, that it has four pin guts and a dummy fifth pin.

Posted By: RapidRobert

Re: why a 4 prong balast? - 09/22/08 01:48 AM

Quote:

Not necessarily. The 4 prong ECu superceded the 5 prong setup and it a plug-n-play replacement. However, the average DIY'er would grump that his new ECU only had 4 pins and not 5 like his original and therefore must be wrong. So there was a dummy fifth pin put in alot of them to satisfy customer demand.

I doubt you can buy a non-NOS 5 pin ECU that actually needs the four prong ballast anymore. You might find a 5 pin unit, but I'll bet, if I was a betting man, that it has four pin guts and a dummy fifth pin.

I thought I had it straight in my head until I read this.

Posted By: 383man

Re: why a 4 prong balast? - 09/22/08 04:31 AM

I have never seen a dummy 5th pin in my life as all the ECU's I have seen in the last 20 years are all 4 pins. Ron

Posted By: Mr.Yuck

Re: why a 4 prong balast? - 09/22/08 02:32 PM

yeah they are all 4 pin but there is a space for a 5th isn't there? Is'nt that the green/red wire you cut?

Posted By: 67 GTX

Re: why a 4 prong balast? - 09/22/08 05:04 PM

You will also have two field wires for your alternator hook up if this is a Year One harness with the electronic conversion. Just a heads up when you get to that point. I went ahead and went to a two field alternator and a 4 prong ballast on my 67 GTX when I used this harness. The later alternator is supposed to be better.

Posted By: Mr.Yuck

Re: why a 4 prong balast? - 09/22/08 05:09 PM

Quote:

You will also have two field wires for your alternator hook up if this is a Year One harness with the electronic conversion. Just a heads up when you get to that point. I went ahead and went to a two field alternator and a 4 prong ballast on my 67 GTX when I used this harness. The later alternator is supposed to be better.

Yeah I plan on using a dual field Alt..

Posted By: JSSuperbee

Re: why a 4 prong balast? - 09/23/08 01:05 AM

I too have the Year One conversion you refer to. I purchased a black regulator that is supposed to be compatible with this set up yet retains the look of the original regulator. However, the conversion harness has a push on triangular shaped connector for the '70 and later type regulators. What did you do about this situation?

Posted By: Mr.Yuck

Re: why a 4 prong balast? - 09/23/08 01:23 AM

I haven't gotten it yet, should be here in a day or two. I think my regulator has the triangle shaped socket.

Posted By: Supercuda

Re: why a 4 prong balast? - 09/23/08 01:29 AM

Quote:

I have never seen a dummy 5th pin in my life as all the ECU's I have seen in the last 20 years are all 4 pins. Ron

Check out www.napaonline.com

5 pin ECU is available, dunno if it is indeed a dummy fifth pin or not. Only one way to tell.

Posted By: 383man

Re: why a 4 prong balast? - 09/23/08 04:05 AM

I guess what I mean is I just dont see anyone selling the 5 pin ECU's around here as you just dont need it. It's always the 4 pin that the parts stores sell around here and of cousre the MP are all 4 pin. But since you can use the 4 pin ECU on any of the 4 or 5 pin wired cars it kinda makes sense to only sell the 4 pin ECU's.

Ron

Posted By: Crazy73

Re: why a 4 prong balast? - 09/24/08 12:54 AM

Quote:

Check out www.napaonline.com

5 pin ECU is available, dunno if it is indeed a dummy fifth pin or not. Only one way to tell.

Tongue test!