Wiring issues and O2 sensor (1 Viewer)

[jeremy56]

So I replaced both 02 sensors with Oem a while back and still got the 25 code for lean fuel. I'm trying my hardest to troubleshoot and found this mess of wiring issues on line that goes to 02 sensor. Its in a horrible spot and I need some guidance. How to test for if this is root of the problem? It has to be but want to know. I have a multimeter but not sure entirely what I'm doing. The end of harness connector with the orange wire is reading 12 volts with key on. The others are not? Are they supposed to? Any body have some insight to what I need to do from here? How would you fix it? I can't find where the wires leave the harness and route near EGr and down to 02 looks like just above starter. I have an extra harness (partial) with similar Guage wires.

 

[jeremy56]

Bump....

 

[baldilocks]

The year of your 80 is pertinent information when asking for help always. I can tell you that 02 sensor wires do not route across the firewall like yours appear to. If this is the case then you are dealing with someone else’s hack job. Your question is rather difficult to follow. Do you have a FSM with schematics and wiring diagrams? You’ll need this now and in the future.

 

[zonker]

This applies whether those wires go to the sensor or not.

First thing I would is remove tape or heat shrink and verify the wire connections are solid. Sometimes wires are just twisted together or the soldering work is really bad. If so.. not good and needs to be repaired correctly.

If it is soldered.. it should not be lumpy or have a dull sheen to it. If it is questionable cut out the soldered section and use some type of butt connecter. Unless of course you are good with a soldering iron. Twisted together.. same thing applies. Cut out the twisted wires and reconnect. Don’t use the wire that “they” stripped.. probably too much corrosion.

 

[jeremy56]

Thanks Zonker, I did find that there's a blue insulated wire that may not have been soldered correctly. I am not very good at it but gave it a shot. I got 12 volts out of two of the 4 now.

 

[baldilocks]

In the future, it is best to use crimped on butt splices and avoid soldering because anything but pro grade soldering can cause problems.

 

[jeremy56]

I haven't buttoned it back up with loom and tape and can still do this with butt connectors. They are super small wires didnt have any connectors that tiny.

 

[zonker]

In the future, it is best to use crimped on butt splices and avoid soldering because anything but pro grade soldering can cause problems.

Couldn’t agree more. Nothing worse than a cold solder joint and trying to find it. Especially when you didn’t perform the task and there is a lot of wire in an 80 Series. Ask me how I know!!

 

[Malleus]

In the future, it is best to use crimped on butt splices and avoid soldering because anything but pro grade soldering can cause problems.

The Wiring Harness Repair manual only specifies crimped connection using sleeve type butt connectors, but that may be to save time in the dealership bay as much as anything else

 

[bigredmachine]

The Wiring Harness Repair manual only specifies crimped connection using sleeve type butt connectors, but that may be to save time in the dealership bay as much as anything else

depending on the repair you order a repair kit that has correct sized crimps, heat shrink and appropriate sized wire. its good enough for repairing air bag wiring, personally in the shop i would just splice, solder and heat shrink my wire repairs

 

[bigredmachine]

use this to check the o2 sensors at the diag connector, since the sensors should be good it could point to a wiring issue if the readings are no good

 

[Rifleman]

but that may be to save time in the dealership bay

You're right, this may save the dealership techs some labor time in the bay . But when it come time for the service adviser to bill the customer. That dealership more then likely is going to bill the customer for the full amount of time that the Mitchell's manual says it takes to do that job . Sorry to say I've seen it happen more then once.