What's this wiring to?

Hey everyone I'm new here and new 2nd gen owner. Its a 1990 3.0 and im trying to figure out what these wires go to. I think far left one is ground to plenum but that's all i got. Truing to figure out if they could be a cause for no power to my fuel pump or if my pump is just bad. Thanks!

 

You sure the one on the left is ground? That looks just like the manual fuel pump prime connector on my Z28...I’m sure someone will chime in....

 

I'm not sure but that's what this forum said. He was having injector problems but had fuel pressure. I'll look into the priming thing though

 

I think the round connector with two leads might be the one that is attached to the knock senor which has a pass through hole with the intake manifold for the wire that goes to the sensor. You may have to remove the throttle body and/or the plenum to get at the connector if it is there on top of the intake and next to the injectors on the DS of the engine if memory serves. The pair of wires are looking to be missing the molded connector that I think is the one that goes to a thermistor on the smallish manifold at the rear of the intake and supplies coolant to a host of temperature sensors. The temperature gauge and two temperature sensors are located here and one is the unit that tells the ECU that the engine is warmed up and ready for closed loop fueling and timing adjustments. Some PO had glued mine into the sensor and I had to destroy the plastic housing to detach it when I pulled my engine for a rebuild. That ground is hugely important as it completes the circuit for the injectors in keeping electrical noise to a minimum. Sorry the connector with the black/red trace and blue wires is unfamiliar. Do you have AC if not it might be for a solenoid that is for the AC but that is a WAG!

 

Well none of them are keeping it from running with the new fuel pump. Got to drive about 50 miles today! Still needs a lot of love and there is a massive fuel injector leak. I have to starve the pump before shut off to keep it from flooding. It does have AC however someone ripped the condensor out. Also I found out 4x4 doesnt work so maybe relevant there. 4 low feels like it engages but doesnt do anything and 4 hi is just dead. Is it possible that temperature one could be for oil? My oil gauge doesnt work.

 

The front axle has a vacuum powered mechanism which disconnects the driverside half shaft from the diff. There is a vacuum powered accumulator canister inside the passenger side wheel well and a bunch of lines withA VSV solenoid to open and close the mechanism for shift on the fly capability of the four wheel drive.

The oil pressure sending unit is down by the oil filter. One wire goes to that sender.