72 Swinger - Some wiring questions.

[vames]

I'm currently cleaning up all my wiring and connections, fixing things that need fixing along the way. The FSM (for a 72 Valiant) wiring diagram has been extremely helpful, though it's still a tough slog. Someone did a crappy black spray bomb in the engine bay a long time ago, covering the true color of a lot of wires. And there's a lot of grime under my hood -- I've been too busy driving this car for the past 20 years to worry about cleaning anything -- it all just worked dependably. But it is pretty wretched in there. I want to tidy it all up before I do a red spray paint job on the engine bay.

There are certain things that I'm having trouble identifying. Any help is appreciated. The pictures are marked with numbers for reference:

1) There is a small sub-harness coming off the passenger firewall that isn't plugged into anything. Three wires (two are on the same terminal). They all appear to be blue(!!). At the firewall, these wires bundle with the wires coming off mystery item #2.

2) This thing is attached to the cowl on the passenger side. As mentioned above, its wires bundle at the firewall with item #1 above.

3) There is what looks like a dark blue wire coming out of the bulkhead connector. In all the years I have owned this car, it has just dangled, unconnected to anything. I've confirmed that it is switched power from the ignition switch. In looks like position N in the bulkhead on the wiring diagram, which would split and lead to the ballast resistor and the alternator. But again, the car functions as it should, so there are no known symptoms related to this not being hooked up.

Thank you in advance for any insight or ideas.

 

[Super-Cuda]

Interesting!

My guess...

The car originally had points ignition system and is now changed to electronic ignition that comes in a kit from Mopar with a new wiring harness. Maybe the electronic ignition was installed leaving the old harness intact and unused??

 

[67Dart273]

On the cowl device, get into the FSM in the emissions section. So far as anything connected back to the bulkhead, get into the diagram and find out specifically what pins it connects to. That cowl device I believe is part of the NOX system

Aftermarket diagrams, NOT in the FSM, are sometimes easier to follow, but often leave out options and connectors, as well as not diagramming connectors as to shape for ID

Also EVEN THOUGH it is quite different, you might try going to MyMopar and download the 73 manual, as the wiring diagrams are set up differently, more detailed in some respects--and--back in the pages beyond each diagram are charts diagramming specific connectors as to shape, etc. Again, that year is DIFFERENT, but some of these odd details might "show up."

 

[Mattax]

That cowl device I believe is part of the NOX system

And the 1972NOX tied to the Ignition Circuit.
Illustrated here.

from here p.13 Evolution of the Cleaner Air System (Session 287) from the Master Technician's Service Conference

Not all 1972 cars seem to have it. This one clearly did

Solenoid may have mounted on the inner fender.

 

[vames]

OK -- the NOX system -- now we are getting somewhere. Thank you.

This is an original California car, and the FSM says "NOx CONTROL SYSTEM: The NOx system is installed on vehicles sold in California to control nitrous oxide emissions."

I know that the vacuum port on the carb is hooked directly to the vacuum advance on the distributor (no solenoid in between). It has been like that ever since I've had the car, so I assume that the system was disabled a long time ago.

So the item in #2 in my pictures appears to be the Control Unit, which senses temperature and receives info from the Speed Switch on the transmission. That feedback tells it whether to block the vacuum advance.

And the plug in #1 might have gone to the (now non-existent) timing-retarding solenoid valve. I did a continuity test between the terminals in the dangling plug in #1 and the control unit plug in #2 and it indeed checks out according to FSM the wiring diagram for the NOX control system.

I assume I can gently remove these items with no ill effect? They seem to be a control system for a valve that is no longer there. Or should I add a solenoid valve and try to get the system working again?

 

[Mattax]

With the rebuilt 318 its hard to know what cam is in the engine and what distributor they installed. If the distributor still has its tag on the side, then it we can take a look at the books. When they get opened up, and when they get rebuilt by a big operation (eg Cardone) the tag gets tossed. That's not a big loss because they don't neccessarily keep the springs and governer together with the distributor body they came out of.

Why am I going on about this.
Because without knowing the cam and distributor were intended for use with that NOX reduction system, I wouldn't use it.
Even with the original engine and distributor I'd be on the fence. I know the later version (OSAC) made a noticible lag in throttle performance. Enough that it would make you unhappy driving it.

So I say no. If its been OK like that, leave it off. As far as the wires and surviving pieces, I'd probably leave them just to keep the wiring neater and the ends out of the way. For the connector to the missing solonoid I'd use a small zip tie or two. Maybe some electrical tape around the exposed terminals if you think they could contact a ground.

 

[vames]

If its been OK like that, leave it off.

Thanks for telling me what I wanted to hear. The rebuilt 318 runs great without it. Hell, even the original 318 (which probably did have the cam and the distributor that were made to run it) ran fine without it.

As for the wires -- I agree it would be better to leave them than clip them. But I'll have to look closer -- If I can get them cleanly out of there without disturbing other things, that's what I'm going to do.

Now to figure out what that loose switched power coming out of the bulkhead should go to......

 

[Mattax]

Now to figure out what that loose switched power coming out of the bulkhead should go to......

Likely its the power feed for the system.
Sometimes the design as shown in the service manual was executed slightly differently in production.
That might be even more true with a half year or an option.

I found that with my '67 instrument panel lighting & turn sig circuits. Rally dash redo

The service manual shows the standard harness used a welded junction in the '72 run circuit.
Reworking the NOx controller schematic as a simple add on to the standard harness, it would look like this:

But apparently you're not seeing a piggypack by the ballast resistor.
So maybe Dodge had an engine harness made for Calif cars. Might have to do with assembly or routing issues, or could be a move to help production.

As far removing, its your car to restore, repair, as you see fit. That is, within the rules you may have to comply with in Calif.
With the screw holes where the control unit mounted to the firewall - those would be worth plugging if the module is removed.

 

[vames]

Thanks Mattax - that makes a lot of sense. I'll have a chance to get my hands dirty tomorrow night and investigate where things are going in there. Clearly there is switched power making it to the VR and the Ballast Resistor because the car starts and runs just fine, so it would make sense that the dangling dark blue was aimed at the NOX system -- just not in the exact way that the FSM is illustrating it.

I love figuring sh*t out, and I appreciate all the help I get from FABO.

 

[vames]

Just to wrap this up - The sub harness for the NOX system came out in one piece (this was really an after-thought add-on in Calif in 1972 - at the ballast resistor connection - there was a terminal that just sandwiches between two regular terminals). The advance restricting valve is long gone. And the hole where the controller was was plugged nicely by a 1” body plug and a couple of screws. The last bit is the wire from the speed sensor in the trans - i left it and taped it off.

I’ll left the switched ignition dark blue wire capped near the bulkhead connector in case i ever find out where it goes.

Now, knowing now that this is an original California car, it’s time for me to go in and plug the always-open EGR jets in the intake!