Alright so I have a 87 gxl with some real serious wire problems. The first one is the emissions harness everything about emissions have been mostly cut off at this point. I have made a list of the connectors and crossed off the ones that are still on.

1. Injectors RS RP FS FP
2. Solenoid valve
3. Air bypass solenoid valve
4. Throttle sensor
5. Variable resistor
6. Pressure sensor
7. Air flow meter
8.ATP sensor
9. O2 sensor
10. Control unit Bb-15
11. Control unit Ba-25
12. X-15 & X-16


But with all that I know I need 4 injectors , tps, variable resistor, airflow meter. I am trying to put this back together with just what is needed to run this car. So far what I got seems complete... and air intake temp sensor and O2 sensor wire to.

 

Dream of a Used harness that you can buy.

 

That is how I am doing it... its almost like **** now! I can almost relate to Bender when he looks at naked robots! I have learned quite a bit about anatomy . Just making sure I dont add to much back on I still have a few connectors left and dont want to put them back on if not needed. It is still somewhat confusing tough...

 

you would probably be better off just buying a used harness and taking off what you don't need versus taking a chopped up harness and putting on what is missing. this is where most people run into problems with unknown parts and trying to dig themselves out of a hole. start with working parts and work down, not start at the bottom and work your way up.

you will also need one more major one, the ECT sensor.

 

As a matter of fact I still have this on the harness. I read up on it to make sure I needed it and I do. it is to read them coolant temp and then adjust the fuel and air accordingly to that temperature it is reading from the sensor. And the connector is just one little plug that goes under the oil filter. I really want to make sure this is done right because like you said it would be better to buy one and take things off then but I do not have the money and I have this one that has most if not all connectors I need to make it work...at least that is my hope...again theres a bit I am still confused about...ha

 

If you are confused now,you will be more confused when it may not work.And as you said,you want to do it right.I wouldn't trust a hacked up/half *** soldered harness over a newer one that actually has the connectors from point A to Point B.
My 2 cents is get a used harness identify and hook up what you need need and then take the rest off if you are deleting it.
Used N/A harnesses are a dime a dozen.

 

Mostly because of confusion and way lack of knowledge I am going to get a new one and do it that way. I do want to do this right and not take any chances so like you said I am not going to take any chances on a hacked up harness. I am not going to waste time with it and with the new one I buy MAYBE use it as a guide to redoing the old one just for fun at this point and to gain some knowledge about it.

 

the ECT sensor is a 2 wire connector located on the back of the water pump, the single wire connector under the oil filter is for the temperature gauge in the dash and does not send a signal to the ECU for fuel corrections.

 

It's Dangerous To Go Alone, Take This: Foxed.ca

RotaryEvolution is spot-on here. The smart move would be to get a complete harness instead of trying to cobble the required connectors (IF you can find them...) onto the one you have and risk questionable connections. Also, I'd like to point out that the S4 FSM doesn't use the "X" numbers you referred to. Those two connectors are called FEM-01 & FEM-02. I prefer this nomenclature as it tells you which harnesses the connectors link together. In this case, it is the Front and EMissions harnesses. I'd STRONGLY suggest downloading the S4 FSM from the above linked site.