Where does the O2 sensor plug in (no, not a joke)?

[BigEasy]

Truck's been running a little rough lately, so I decided to install some new plugs & wires today, new oil & filter, & a new O2 sensor. When I reached up to remove the old sensor, the connecting wire was just hanging there. Don't know if it was that way when I bought it, or it recently came loose... But the problem is that I can't find the plug to plug the new sensor back in! I've been on top of the motor and under the truck 3 times each, still don't see it... The only thing close are the wires coming from the tranny and the spark plug wires. Can somebody PLEASE tell me where the other plug comes from (what wire loom/direction/etc.)??? Also, it's a '90 GMC Jimmy w/5.7 TBI if that matters.

 

[fortcollinsram]

it is a purple wire on the driver side of the engine...Has a barrel-type weather -pack connector..

 

[BigEasy]

it is a purple wire on the driver side of the engine...Has a barrel-type weather -pack connector..

Ok, purple wire... I kinda figured what the connector should look like by the connector on the sensor. Can you tell me where the purple wire runs to? I don't see anything coming off the main ECM up by the brake booster, and there doesn't appear to be anything coming through the firewall or coming out of the loom where the tranny wires are. This has me totally stumped, and it's something so simple that it's frustrating the hell outta me...

 

[southernspeed]

As far as I can remember on mine it came out of the plastic sheathing on the loom that runs across the bulkhead behind the dizzy. Single purple wire with the connector as mentioned. That then runs off to the ecu.

 

[dyeager535]

Isn't the sensor port on the TBI trucks in the drivers exhaust manifold, sort of angled toward the firewall?

And yes, the O2 wire will be in the loom, going to the ECM through the hole in the firewall on the passenger side with all the other ones to the ECM.

 

[sweetk30]

left head side of the block at the big wire loom . mine just bairly hangs out of there.