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Thread: Quick wiring question
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mwpayne1
Redlining
Posts: 239
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posted October 31, 2006 05:56 PM |
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Quick wiring question
In putting together the interior I ran into a couple of wiring plugs that I neglected to mark when disassembilng two years ago.
To the left of the drivers left knee, there's a control box with two plugs on the backside of it. These plugs are interchangable (at least on my '74), which goes where? I did notice on one plug theres a double green wire on one pin, does it go top or bottom? (My box has the plugs facing the firewall). There's also a ground wire on that box..I assume it's ok to just attach it to one of the box mounting bolts?
Thanks!
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klaus42
Rotorhead
Posts: 1877
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posted November 01, 2006 10:04 AM |
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The simplest method...
...would seem to be to try them one way, and if that doesn't work, try them the opposite...?
(I'll have to go look; the one of mine easiest to look at also happens to be disassembled...)
*You're probably already aware of this, but the ground for that box happens to be one of the problematic ones, most often... IMHO at least in part due to the mounting screws/bolts going clear thru the cab, and being exposed in the vicinity of the front wheel...resulting in rust and corrosion. (I've broken a number of these clean off...)
Actually, that box --and the accompanying ground-- is still suspect in my main electrical snafu of the year.
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bliffle
Revvin Up
Posts: 95
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posted November 01, 2006 12:51 PM |
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OK, so what is that box for? I've noticed it several times and wondered what it's for, especially now that I have to track down a headlight shorting problem that blows fuses during the rainy season.
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mwpayne1
Redlining
Posts: 239
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posted November 01, 2006 01:56 PM |
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I don't know myself, I'm guessing it controls things like signals and wipers. My field electronics experiences have prevented me from 'trying them both ways', as I have been known to 'let the smoke out' of components doing that.
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sparky
Redlining
Posts: 299
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posted November 01, 2006 03:06 PM |
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If I remember correctly it's an emmissions controller. I think it turns off the supply voltage to the trailing coil.
____________
'77 REPU
Stock 6-port
T-2 tranny
Weber IDA 48
Alum Flywheel
3rd gen Torsen in rear end.
DLDFIS ignition
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bliffle
Revvin Up
Posts: 95
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posted November 01, 2006 11:07 PM |
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quote:
If I remember correctly it's an emmissions controller. I think it turns off the supply voltage to the trailing coil.
Hmmm. I wonder what the theory is. Why would it reduce emissions to turn off trailing spark?
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mazdarx605
Redlining
Posts: 314
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posted November 02, 2006 04:01 AM |
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I believe the theory of shutting down the trailing spark had to do with the fact that they were using thermal reactors back then instead of catalytic converters.I know my RX-7 also had that system when it had the points ignition,and I think I read it was an emmisions thing that had to do with the thermal reactor.I could be wrong though.
Chris
74 RE/PU "Green"
79 RX-7 GS "Spark Yellow"
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dhood
Hauling
Posts: 134
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posted November 02, 2006 06:58 AM |
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I thought the emissions control box on pre 77 was under the drivers seat, but I could be wrong about that and I have no EWD to verify. There is another box around there which controls the wipers and flasher units. If it is the ECB, the spark is cut during low rpm cruising to richen the exhaust mix. This is needed so the thermal reactor has enough fuel to burn the exhaust mix. If it is too lean, combustion can't happen. This is the main cuase why carbed rotaries fail emissions, techs want to lean out the carb to clean up the exhaust which is impossible, so the reactor doesn't work.
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jfaplanet
Redlining
Posts: 356
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posted November 02, 2006 08:30 AM |
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Wipers and turn sigs
The box he is refering to is the wiper and turn sig relay box.
The shop manual has a diagram and diagnostics procedure at the back. Mike do you have a shop manual. I think I can hook you up. Let me know. crgj@bellsouth.net
____________
74 REPU "Red"
74 REPU "Jethro" "TII"
74 RE-Courier vert
79 SA-SE(aka deathtrap)
79 SA-SE-FC (project
turbo)
http://home.bellsouth.net
/p/PWP-crgj
TN Forum:
http://tnrotary.10.forume
r.com/
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klaus42
Rotorhead
Posts: 1877
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posted November 02, 2006 10:54 AM |
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Sorry I was so lazy!
...and, of course, you are correct, Charles. Section 15-E of the Shop Manual refers to this box as the 'Central Control Unit'...and as it appears from illustration Fig. 15-7 of the central control unit coupler, the all-green wire would be on the top of the left most plug...(?)
On one of my REPU's, this is the plug on the bottom.
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bliffle
Revvin Up
Posts: 95
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posted November 02, 2006 12:51 PM |
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OK, so what is that box? Do we have a consensus?
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sparky
Redlining
Posts: 299
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posted November 02, 2006 06:47 PM |
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OOPS....I gues I was wrong about the control box. I thought the emmissions controller was the one mounted on drivers side kick panel. As far as the logic behind cutting out the trailing coil to reduce engine emmissions: I remember hearing that the factory carbs are jetted to run A/F mixture around 5% rich for the purpose of burning out emmissions in the thermal reactor. If the trailing coil is tuned off then there would be an increase in the amount of unburned fuel in the exhaust. This would allow reduced emmissions. On another note. An engine burning rich will have lower combustion temperatures and less excess O2. This would further reduce the formation of NOx.
____________
'77 REPU
Stock 6-port
T-2 tranny
Weber IDA 48
Alum Flywheel
3rd gen Torsen in rear end.
DLDFIS ignition
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klaus42
Rotorhead
Posts: 1877
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posted November 03, 2006 12:31 PM |
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Yes, Bliffle...
...it *is* the wiper/horn/turn signal/flasher relay box.
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