Chrome Box 4 pin ballast question

[matt63]

Maybe I'm just looking for problems here but there was a recent post about the use of 4 and 5 pin ECUs and 2 and 4 pin ballast resistors.  Currently I'm running a chrome box with a 4 pin harness and a 4 pin resistor.  Is this wrong?  According to the diagrams I've seen it is.  Would this hurt performance by reducing the coil voltage? Thanks.

[nivvy]

let me look. I have a chrome box in the garage.... been sitting around... you can have it... 

[matt63]

let me look. I have a chrome box in the garage.... been sitting around... you can have it... 

Thanks but I have one - just unsure if I've got it hooked up properly.

[Moparal]

The 5th isn't needed. What you have will work

[Chryco Psycho]

 
with a 4 pin ECU you are only using 1 side of the ballast , you can use a 2 pin if you want , but is makes no difference to the coil assuming you have the polarized connectors on the ballast

[matt63]

Thanks.  There is wires going to both sides of the ballast.  I am concerned that I am knocking the voltage down too much.  I haven't got a pic yet but can get one tomorrow.

[Chryco Psycho]

on one end you will have the blue or blue yellow trace  12v feed , on the other you have two brown or 1 brown & blue to the coil & the green/red trace wire to the ECU the green/red wire is not used with the 4 pin ECU

[matt63]

I had a quick look but didn't check voltage into the ballast resistor although I only have about 3.5 volts to the coil. The ECU plug is still the 5 pin unit and not 4.  On the 4 pin ballast I have 2 browns on one end and a blue on the other.  The blue jumpers across to the other side where there is another blue wire.  On the other end of that side is the green w/red.  I'm assuming that this side doesn't do anything with the chrome box having only 4 pins???  I'll go and check the voltage into the ballast now.  Thanks.  Hey, it's only -30C right now.  I am sure enjoying my new garage CP! I am sure glad I'm off to Phoenix and Barrett Jackson next Saturday. 

[Chryco Psycho]

you should be 13v on the blue wire 8v or so on the brown & the green doesn`t matter
 - 27 here with the north wind pounding , I can`t understand why you appreciate the garage 

[matt63]

you should be 13v on the blue wire 8v or so on the brown & the green doesn`t matter
 - 27 here with the north wind pounding , I can`t understand why you appreciate the garage 

Yeah It got to the point that the sight of my old tiny dim dank cold garage would cause me to return to the couch with my blanky

As far as the BR goes I've got 11 volts in and 4 volts out (run position / car not running / battery at 12.5 volts).  It sounds like the ballast resistor is knocking the voltage down too much perhaps.  I have another 2 pin resistor I can check out.  Perhaps I should just swap them out.  Do you think low coil voltage would hurt performance?
 

[Chryco Psycho]

absolutly , you need more voltage at the coil to create a strong spark , low voltage in = weak spark out
 swap in the 2 pin resistor or buy a newer low ohm performance resistor

[71chally416]

Maybe this will help. There's more info here>
http://www.moparts.org/Tech/Archive/elec/3.html
 

[MEK-Dangerfield]

Chryco is correct. With the key in the "on" position, you should have around 8v on the "+" side of the coil.



  Mike

[matt63]

Now I'm wondering how much better it will run.  It's supposed to be above freezing on Monday so perhaps I can open the door and fire her up.  I never really had any issues with how the car runs although I probably have less than 500 miles on the car.  I have always thought that it didn't sound too crisp at idle though.  Perhaps this will help. 
I do have a selection of 2 pin resistors which includes a new one that is about 1.1 ohm cold.  It's a little odd as there is a metal bracket for securing it instead of just a hole through the body of it. Thanks again guys.

[Chryco Psycho]

the metal tab is the original design , not sure anyone repros those