Ignition wiring and VR questions

[HT413]

Could someone help clear up some questions about ignition wiring and voltage regulator? My voltage always did vary with rpm from 12.5ish to 14ish (voltage gradually and smoothly increased with rpm) but i took this as normal. Now suddenly it is gradually reaching 17 as i rev it to so i figured the voltage regulator was shot. (It was converted to the '70 and later transistorized VR by previous owner).

I replaced it and the new one is rapidly fluctuating from 12ish to 15ish when i rev it to anything much above idle, meaning if its at a steady 2000 rpm, the lights flicker and the volt meter shows rapid fluctuations between 12ish and 15ish volts a bit quicker than once per second. Car runs fine though.

Can anyone shed some light on this problem? (Pun intended.) Its a 69 belvedere, 413, MSD 6AL ignition and MSD blaster SS coil, newer 70 and later transistorized voltage regulator, denso alternator, ballast resistor has been eliminated (all this was done by previous owner). I just replaced the 6al box because the original one (procomp) stopped working. Not sure if whatever caused my current issue also fried the box, so i gotta solve it before i drive it.

i figured i'd go through the wiring to see if there were bad connections / corroded / bad grounds and i just cant figure a couple of the ignition switch connections. I found this info on some other site:

#12 Red= Battery feed
#12 Black= Accessories
#16 Blue= Ignition 1 (run)
#14 Brown= Ignition 2 (start)
#18 Yellow= Start

Questions:
1) why 2 ignition circuits (run and start)?
2) the blue (run) circuit also feeds gauge power as well, right?
3) i once read that a bad high beam selector switch can cause crazy voltage fluctuations. Is this true? I did replace mine with a rockauto piece about a year ago but it seems to work fine.

 

[WileE]

It's designed to have different voltage during the turn-key start-up. The wiring diagram will show which wires feed what. From what you say, I'd check all connections & grounds, if the VR is good. Don't forget, voltage is pressure... it's like a water pipe that's blocked & causes the pressure to rise if it can't flow to where it's supposed to go.

 

[Pops1967GTX]

The IGN 1 & 2 circuits ...crank/run, one is hot only when cranking, the other hot only in run.. Thats in the harness.


http://www.msdignition.com/instructions/Products/Ignitions/6420.pdf?terms=6420



http://www.forabodiesonly.com/mopar/showthread.php?t=236822

 

[HT413]

It's designed to have different voltage during the turn-key start-up. The wiring diagram will show which wires feed what. From what you say, I'd check all connections & grounds, if the VR is good. Don't forget, voltage is pressure... it's like a water pipe that's blocked & causes the pressure to rise if it can't flow to where it's supposed to go.

Thanks for the input. I was sort of thinking in the same direction about there being too much resistance. After some poking around I found a couple of the splices kind of weak looking and none of them soldered.

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The IGN 1 & 2 circuits ...crank/run, one is hot only when cranking, the other hot only in run.. Thats in the harness.


http://www.msdignition.com/instructions/Products/Ignitions/6420.pdf?terms=6420



http://www.forabodiesonly.com/mopar/showthread.php?t=236822

Hey thanks for the links, just what I needed to see. Also, thnks for the explanation, makes sense.

 

[HT413]

Little update, I tracked down a post (cant remember if someone here suggested it) from Moparforums that says voltage drop from the + terminal on the battery to the blue wire on the VR should be less than 0.2V and 0.5V or above is a major problem. To be honest, I have no idea if this post is correct but seems to make sense at least in spirit.

http://moparforums.com/forums/f84/voltage-regulator-11861/

Well I had about 0.9V drop. So I cleaned up connections from bulkhead to alternator, ign, and VR and got it down to 0.7V. I then cleaned the bulkhead spade connectors as well as the ignition switch spade connectors (female ends will have to be another day - not even sure how I'll do that). Got it down to 0.4V. Jumped out my ignition switch and still had 0.4V, so the ignition switch is good.

Started it up and it still is around 15V. Next I'll clean up the female ign terminals and female bulkhead terminals and I'll be good.

I'm considering replacing the bulkhead connector and putting in some new female terminals. Anyone attempt this?

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I think i'm going to try the salt and vinegar method on this site to clean those female connectors. Maybe the salt, vinegar and flour paste.

http://m.wikihow.com/Clean-Copper