Hi guys. Im new to Mopars. Im a Ford guy for the last 30 years and Im trying to figure out this Mopar charging system.
I have a 68 Charger 318. I upgraded to Alternator to a dual field powermaster 75A unit. I changed over to the electronic voltage regulator and re did the wiring mod that is required. The motor has an MSD electronic distributor which requires 12V. Also has an electric fan and higher power headlights 90w/100w. Here is my problem...
The amp meter NEVER shows a charge, usually -10 or so and with headlights on -20 to -30. I know these fluctuate a lot but this is extreme. The regulator is working fine and the battery is getting about 13.5 volts at idle. When I turn on the headlights I get about 12.7 to the Battery. I wired in a second battery wire from Alt to starter solenoid with a fuseable link, since I read it helps alleviate wiring problems for the firewall connections. I have tried everything to try and figure out why the meter shows such a discharge. I had to remove the ballast resistor to the coil and Ign 2/regulator wire because the ignition needs a constant 12V at start and idle. I tried putting the ballast back on just the IGN2 wire but then it wouldn't start because the diminished Voltage during cranking. The headlights and dome light pulse brighter as the rpms go from idle to cruise and vice versa. The fan is wired thru a relay and pulls power from the battery (should I pull power from the ignition supplied 12V instead?)
How can I make it so the lights/headlights are steady and don't change brightness?
How can I fix the charging problem? Is there a trick with these mopar systems? Im used to the Ford 1 wire plug and play, so you can see why Im feeling so stupid right now.
I feel the problem has to do with a power drain somewhere but there are no shorts, grounds are good at ALT and BATT, etc. When I disconnect the fan relay during idle, nothing happens on the ammeter indication so it seems that isn't the problem either.
Any help or experience on this guys?
Thanks,

 

With a 75a alt. you should be rewiring the charging circuit and eliminating the factory amp gauge !!!! IT IS not up to handling the 75 A alt Check posts in forum

 

Please read this............

http://www.madelectrical.com/electri...p-gauges.shtml

These car's wiring were marginal when built. Even "back then" if you got the optional 60-65A alternator, Ma modified the wiring what has become known as "fleet/ taxi" which ran heavier wires into the interior in separate gromments. The big problem, as outlined in the article is under rated ....and nowadays....corroded/ loose/ damaged bulkhead / firewall connector terminals.

The main issues are.........poor design of bulkhead connector, marginal wiring size for charging line, and the ammeter itself.

If you decide to convert to a voltmeter, this might give you some ideas. Read all three pages, as it covers a number of the A body clusters. I'm sure you could do the same to a B

http://www.forabodiesonly.com/mopar/...d.php?t=119480

Harness voltage drop is a big problem with these girls. The ignition feed path (originally) is

battery......starter relay junction......fuse link......through the bulkhead.......ammeter..........ignition switch connector........through the switch......back out the switch connector........back through the bulkhead

Every one of the mentioned points is subject to damage/ corrosion and can be the cause of drop, which is additive. Also, in rare cases, (refer to the MAD diagram) the in harness splice (welded splice) can fail. This IS rare, but can and does happen.

 

Thanks!!! I just did that mod today after reading it. Now we will see if it works better after I get a new cluster voltage regulator.... the original one decided to throw full voltage to my gages just as I got things buttoned up on the dash. Murphys law strikes again.

 

"Go through" your cluster. The typical problems with all these cars............

Connector pins get loose/ corroded broken at the harness connector on the PC board. Solder or repair

The brass spring contacts for the instrument limiter are crimped into the board and may not be making good contact with the board traces. Solder jumper across

Of course you need a good IVR. RTE engineering is one

Loosen/ tighten the nuts on the gauge studs several times.

You can check gauge accuracy by "rigging" test resistors in place of the senders once you get a good IVR. low end of the scale is about 70-75 ohms, mid scale is 23-25 ohms, and full is 10-15 or so

For example, you can buy a pack of 4 -- 100 ohm, 1/2 watt resistors from Radio Shack. Wire all 4 in parallel which gives you 25 ohms. This should put the gauge under test at 1/2 scale. All the gauges are same movements.

 

I have some electrical questions which are driving me bonkers but theres not a Staret new thread ANYWHERE!!!!! How do I start a new discussion??

 

I'm pretty new here also but I think if you go back one page there is a "new thread" button at the top left of the page.

 

What is the easiest way to change the bulkhead connector on a 69 charger?