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  #1  
Old 10-08-2003, 02:59 PM
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ttraut@unlockit ttraut@unlockit is offline
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Default Engine wiring harness and MSD6A

After dealing with electrical issues all summer, I bought a new engine wiring harness from Year One for my 383 69 RR.

I have MP electronic ignition with an MSD 6A ignition box and MSD Blaster 2 coil.

I don't remember how the wires hook up and my old wiring harness was too butchered up to be of help.

Here's a picture of what I have (that isn't working). I need someone with an MP electronic distributor and MSD 6a box to give me some help.

As you can see, I have the ballast resistor disconnected; it's attached to the firewall for ornamental purposes only!

I jumped the two wires that had been connected to either end of the resistor. I believe that's what I had before disconnecting the old wiring harness.

The wire going into the battery end of the voltage regulator consists of two wires: a blue one and a blue one with a white tracer.

Q: Is this the correct setup for the voltage regulator with electronic ignition?

I have one "leftover" connection that Year One couldn't help me with (and that I didn't have on my old wiring harness): I have a small ring terminal attached to a blue wire out by my alternator that currently isn't connected to anything; should it be? The alternator is connected via a large ring connector and the field blade connector.

Q: What is this "extra" ring connector?

Thanks!

Terry
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  #2  
Old 10-08-2003, 03:20 PM
451Mopar 451Mopar is offline
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#1. Are you triggering the MSD directly from the distribitors magnetic pickup or from the MP electronic ignition box (old/original negative coil connection connected to MSD white trigger wire?)

#2. With the MSD you don't have to remove or jumper the ballast resistor. The voltage from the ballast resistor (old/original positive coil connection) just connects to the small red wire on the MSD and this voltage just lets the MSD box know the ignition switch is turned on so there is almost no current flow through this wire.

#3. You probbably already know this but the large MSD red wire goes directly to the battery positive and the large black wire need a very good ground connection.

#4. The coil should only be connected to the MSD wires. I think these are orange and black? I don't have a schematic to reference right now, but I think those are the wires.

I don't know about your ring connector, can you take a photo of it? I would test it to see if it has power with the ignition on.
Because it is blue wire, same as the key-on power going to the regulator it may be part of the same circuit?

MSD does have a web suite with wiring diagrams if you need one.
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Old 10-08-2003, 03:22 PM
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creative1 creative1 is offline
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the only other connection on a big block anywhere near the alternator is the water temp sending unit. the wire on my 84 D250 (which I put a 440 in) is orange, but i dont know if that is because it was originally for a small block or because i added it cause the connector fit. i had to lengthen the wires when i put the 440 in.
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Where are we going?... And why am I in this hand-basket?
84 D250/440/3.54:1 dana 60/16" wheels, 31" tires/A-727trans/3" header mufflers/weighs 5000 lbs/13.22 sec @ 103+ mph.
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Old 10-08-2003, 03:52 PM
451Mopar 451Mopar is offline
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DUHH!!
I just figured out that the ring connector is!
This wiring harnes is for a big block which originally has the coil mounted up front by the distribitor. The ring connector is most likely the old/original coils positive power connection from the ballast resistor. This is the wire that would go the MSD small red wire that lets the MDS know the ignition is "ON".
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Old 10-08-2003, 05:24 PM
John Kunkel John Kunkel is offline
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The MSD website has help:

http://www.martelbros.com/msd/support/msdsupport.htm
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Old 10-08-2003, 07:12 PM
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ttraut@unlockit ttraut@unlockit is offline
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Thanks you guys. I'll answer the questions and see if I can redirect you so you can help nail this thing.

#1. Are you triggering the MSD directly from the distribitors magnetic pickup or from the MP electronic ignition box (old/original negative coil connection connected to MSD white trigger wire?)

A: I have a Mopar distributor with electronic ignition. There are two wires coming from the distributor and going to the MSD6a. This set up was working before I replaced the wiring harness so I'm pretty sure it's okay.

#2. With the MSD you don't have to remove or jumper the ballast resistor. The voltage from the ballast resistor (old/original positive coil connection) just connects to the small red wire on the MSD and this voltage just lets the MSD box know the ignition switch is turned on so there is almost no current flow through this wire.

A: I don't know what the old/original positive coil connection is since I've had the MSD6a+Blaster 2 coil setup for a couple of years and it was working fine. I tested the small red wire to make sure that it was switched hot and it is.

#3. You probbably already know this but the large MSD red wire goes directly to the battery positive and the large black wire need a very good ground connection.

A: I have mine connected at the starter relay which is connected to the battery. New cables all around (and it was working fine. I'll check the ground.

#4. The coil should only be connected to the MSD wires. I think these are orange and black? I don't have a schematic to reference right now, but I think those are the wires.

A: Yep. You're right.

I don't know about your ring connector, can you take a photo of it? I would test it to see if it has power with the ignition on.
Because it is blue wire, same as the key-on power going to the regulator it may be part of the same circuit?

A: I think you're right about the coil connector for a 440. This harness is for a 383 or 440. I taped it off.

A: I tried starting the car without bypassing the resistor and it didn't help.

REDIRECT: I think I'm screwing up the voltage regulator connection somehow, or would screwing it up not affect whether the car started? I have the connector with the dark blue and dark blue with white tracer going into the battery side of the regulator. Is that correct?

I printed the diagrams from the MSD website and compared them to my installation guide and they match so I'm PRETTY sure the MSD setup is good.

Q: Why else would I not be getting electricity? And how might I check to see if I'm getting spark at the coil and at the distributor (without frying myself or components)?

I'll try the ground on the MSD6a and then try again. Meanwhile, keep suggesting.

Thanks,

Terry
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Old 10-09-2003, 10:39 PM
451Mopar 451Mopar is offline
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Lets start with the voltage regulator connections. I think they are OK, but here is what you should see.

The blue wires at the voltage regulator "IGN" connection should have battery voltage when the ignition key is switched "on".

The output of the regulator "FLD" connection will have some voltage on it, going to the alternator field connection (with the key on.)

The blue wires at the ballast resistor are the same circuit as the blue wires at the regulator "IGN" connector, so the ballast resistor should have battery power too.

The Dark blue wire with the ring connector is power from the ballast resistor, normally connected to the ignition coil. With the MSD this wire or other connection on the blue circuit should be connected to the small red "power-on" signal wire for the MSD.

If you have power at these places, and the large red and black wires are connected correctly to unswitched battery power, and the coil is connected to the MSD coil wires as noted earlier, then you may have a problem in the triggering circuit.

Because your using the magnetic trigger wires from the distribitor, make sure the white wire is not connected to anything.

You can check for an output spark at the ignition coul by momentarly grounding the white wire should trigger an output spark from the MSD.

You could also remove the distribitor and spin it by hand to see if the MSD is outputting a spark.

If yout getting a spark at the coil make sure the distribitor rotor is installed, then check for spark at the end of the plug wires.

If you get backfires, make sure the distribitor is not installed 180 degrees out of time with the engine.

I would also run the MSD large black ground wire to the battery negative, and use a negative battery cable that has the extra small wire to connect to the body ground / MSD ground.
Same for the positive battery cable, using a cable with the extrs output wires.
The reason is if the battery cables are getting bad, they drop alot of voltage when cranking the starter (high current load), Also, connecting closer to the battery will reduce possable voltage spikes / fluxuations (sp) from the voltage regulator.
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  #8  
Old 10-11-2003, 12:51 PM
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ttraut@unlockit ttraut@unlockit is offline
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Default There's a difference

451Mopar, John, and creative1,

Thanks for your help. It's now working. Here's what I did wrong: I thought connecting the red wire from the MSD6a to an accessory was the same thing as connecting it to a switched lead. I realize now that there's a difference.

I'll elaborate in case my Alzheimer's kicks in and I have to find this post again....

An accessory lead is hot when the ignition key is turned to the right or left. Things like your wiper and radio run off accessory power.

A switched lead is hot ONLY when the key is turned further right. Your starter is engaged when the key is turned all the way to the right.

I ran wire from the little ring terminal that must be for the coil to the red wire in the MSD6a and everything works fine.

Thanks again!!

Terry
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