86 Chevy underhood wiring - identifying connectors?

[Nick_R_23]

I have a few connectors under the hood I'd like to get an ID on if anyone recognizes them.

#1. Rear center against the firewall. I *think* this may go to the A/C compressor as the wires head from the A/C box.



#2. Drivers side, this one plugs into the transmission vacuum switch, but I'm unsure where the orange connector goes



#3. I believe this is choke (light blue) and head temp sensor (green).



#4. Unsure what this one is...sensors on the carb? Will it hurt anything to keep these unplugged?



#5. I believe these are oil pressure sensor and oil pressure sender. Would this truck have had both?





Thanks in advance for any help!

[Wgesnerjr]

#1 is correct
#2 is correct but the orange is some sort of diagnostic lead. it does not plug into anything.
#3 is correct
#4 the gray connector. I remember having to unplug something like that to adjust timing? Maybe a primitive computer advance? Not sure.
#5 Yes, Oil senders. There would be two. One for the gauge one for the choke circuit.

I am basing this on my 85. When rewiring for my LS swap, I found all these in my truck. Your's may be different. you may want to check a wiring diagram, just to be sure.

[Nick_R_23]

Originally Posted by Wgesnerjr

#1 is correct
#2 is correct but the orange is some sort of diagnostic lead. it does not plug into anything.
#3 is correct
#4 the gray connector. I remember having to unplug something like that to adjust timing? Maybe a primitive computer advance? Not sure.
#5 Yes, Oil senders. There would be two. One for the gauge one for the choke circuit.

I am basing this on my 85. When rewiring for my LS swap, I found all these in my truck. Your's may be different. you may want to check a wiring diagram, just to be sure.

Perfect, thank you! I have a wiring diagram but it's very limited in what it shows. I wish I had a better one.

On #1, is the cut wire just a smaller "subharness" to the compressor? If so, I might just snag one off another truck.

And on #4, since I'll be running a Holley carb and obviously won't need those connectors, is it okay to remove them from the harness?

[gmachinz]

#1 goes dark green to compressor clutch and lt green goes to idle stop solenoid.

[Nick_R_23]

Perfect. I have one more plug. It's on the transmission sub harness (700R4) and is a red 2 prong weather pack connector. From my research this goes to an EGR bleed solenoid, but I really can't find any info on it other than this. From what little wiring diagrams I can find, I believe the trans will still have lockup in 4th regardless of this connector, but it seems that somehow this solenoid affected lockup in 3rd? Do I need to connect these wires together or just eliminate them entirely?

[Wgesnerjr]

Nick,
#4 Unsure. I would check your distributor to see if it will advance/retard without ECM input. I think your answer lies here. My thought would be: If it will function as a stand alone, then eliminate. If not and needs ECM input, may have to keep it or convert over to a non-ECM HEI distributor.

Red 2 Prong weatherpak plug: I do not think the 85 had anything wired to the EGR. If it did, in my case, it was long gone with the original 305 engine. So I am very unsure about this one. In fact most of the 700R4 harness in my truck was cut when I got it. What was left was eliminated during the LS wiring fest.

Sorry I cannot be more help on these.

Jay

[Nick_R_23]

No, that's great info. Fact is on my truck, the original engine is long gone as is the majority of emissions equipment. I will be running a "hotrod" style motor (no EGR, non-ECM HEI dist, no ESC, no CCC carb, etc) so I just mainly need to know if the truck and bare bones things will work with all the emissions deleted. ESC is already long gone as well. I found a trans wiring diagram I'll post up later that may help me figure this out.

[Nick_R_23]

Here's a diagram that seems to match my truck. According to the diagram, the EGR bleed simply uses switches in the transmission to activate, so since the solenoid is no longer there, my lockup should still function correctly.



I also found this excerpt in an older Chilton manual, referencing that the transmission operates the solenoid, instead of the solenoid operating transmission. So I should be okay as far as the lockup working correctly.