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What is this??
https://slantsix.org/forum/viewtopic.php?t=47550
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Author:  Dave'73 [ Thu Jan 12, 2012 1:13 pm ]
Post subject:  What is this??

The small cylinder attached to the coil - with the red wire,

what is this and what is the function??

<img src="http://i1266.photobucket.com/albums/jj528/DaveRichardsonTattoo/IMG_1616.jpg" border="0" alt="Photobucket">

Author:  Fopar [ Thu Jan 12, 2012 1:20 pm ]
Post subject: 

Radio suppression capacitor, keeps spark noise down.

Richard

Author:  Dave'73 [ Thu Jan 12, 2012 5:14 pm ]
Post subject: 

Thanks Richard !!

Author:  Sam Powell [ Thu Jan 12, 2012 6:30 pm ]
Post subject: 

Dave, Good to have you on board. We are here to help you get the most pleasure from this wonderful hobby. Don't hesitate to ask. Does this car run now? I notice the fuel pump is out. Is that part of a larger repair, or is the fuel pump the only thing being done now?

Sam

Author:  Dave'73 [ Thu Jan 12, 2012 7:09 pm ]
Post subject: 

Thanks Sam ! It ran great when I picked it up, and is slowly developing issues,
I am no having some issues with a rough idle and replaced the old pump and a couple other things to just eliminate some variables. I am getting plenty of fuel and I believe the carb is pretty dialed in, so I am now leaning towards electrical.

There seems to be a "miss" during idle, and a slight intermittent surge during driving. I don't even know where to start with the electrical. I have blindly replaced a few things, but nothing seems to make a change(including messing with the carb)??

1973 EI ignition, 83,000 miles, Garage Kept

Author:  Sam Powell [ Thu Jan 12, 2012 7:26 pm ]
Post subject: 

Dave, Look back through the past posts in the electrical section for more complete information on this subject. ONe of the most pernicious problems with these old Mopars is poor electrical connections after the connectors get old. You can do a quick check of the system this way:

With the engine idling, put the leads of a VOM,(multimeter) on the alternator output (the black lead on a good ground) and note the voltage. Then go to the ballast resistor on the driver's side firewall, and test the voltage on both connections coming off the ballast resister. Note the voltage on the high side, and see how much voltage drop there is. There should be very little. Every bit of loss effects the performance of the entire car. This is all accounted for in corroded connectors all throughout the harness. You can then go back down the circuit and see where the losses are. If you do not have a book with a wiring diagram, get one so you can follow the path from alt to ballast resister. A Fctory Service Manual is best, but even the Chiltons manuals have a decent underhood diagram. Chiltons will not have a chassis diagram typically.

The other thing to check is the ground straps. The stock ones are often corroded beyond usefulness, and not doing their job. I have 2 engine to chassis ground straps, plus the battery ground goes right to the block.

Author:  Dave'73 [ Thu Jan 12, 2012 7:33 pm ]
Post subject: 

Thanks for the tips, I'll start checking as soon as I get back from work and post the results. The ground from the battery wire does look pretty shabby now that you mention it, lots of electrical tape and cracked insulation!!

Author:  Sam Powell [ Fri Jan 13, 2012 4:18 am ]
Post subject: 

Sounds pretty typical. The fault mostly lies in the old crimp on connectors. They get corroded. Especially bad are the bulkhead connectors. In time you will learn how to replace those and bring it back up to snuff. Actually better than snuff! :)
Sam

Author:  wjajr [ Fri Jan 13, 2012 4:55 am ]
Post subject: 

Dave73,

Here is a website to bookmark, you will find wire diagrams and other goodies on it.

Bill

Author:  Dave'73 [ Fri Jan 13, 2012 12:04 pm ]
Post subject: 

Thanks Bill!!

I tried taking some voltage readings last night with the engine at idle but the volt meter goes haywire if I even get close to the alternator or coil area???

Author:  Sam Powell [ Fri Jan 13, 2012 4:30 pm ]
Post subject: 

That is odd. I have never experienced that. Does this happen with just the leads in that area, or the body of the instrument as well? What kind of VOM are you using? Describe "goes wild" for us. Does it start to read something without touching the leads to something? Is the meter digital or analogue?

Sam

Author:  Dave'73 [ Fri Jan 13, 2012 4:57 pm ]
Post subject: 

I don't have it in front of me, but I believe it is a Actron/Digital Multimeter purchased at Autozone a few years back. As I get the leads near the alternator the numbers just start jumping up and down, all over the place, just random. Continues to go nuts even with contact. I stick it on the battery pretty solid read out no problem.

Author:  Sam Powell [ Fri Jan 13, 2012 7:13 pm ]
Post subject: 

What is the read out at the battery? What is the readout at the two ballast resistor contacts?

Sam

Author:  Dave'73 [ Fri Jan 13, 2012 7:44 pm ]
Post subject: 

Battery is 15.2 or so, and the top connectors on the ballast resistor are some where around 14.5, I have an analog volt meter I'll throw on this weekend and write down some #'s

Author:  Sam Powell [ Sat Jan 14, 2012 7:19 pm ]
Post subject: 

That voltage at the battery a little high. I would suspect the wires to and from the regulator may have high resistance in them. .7 drop between battery and ballast is not terrible, but not as good as you would like. I think a drop of .2 volts is doable,and better. None is best, but not likely with the age of everything you have there. Before I started rewiring, my car saw a voltage drop of 1.5 volts. That was costing me a difference of 5 MPG. 13 on average before, and 18 on average afterward.

Any ideas out there on what is causing his meter to crazy when he tests the voltage at the alternator? Could it be super leaky coil to dist wire?

Maybe new spark plug wires are in order.

Sam

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