Michigan Motorsports TPI TBI 3-Wire Heated Oxygen O2 Sensor Wire Harness Adapter - Fits IROC - 48" Lead - Compatible with AFS74

I really liked the price on this, but the plastic connector did not fit well at all on my ACDelco sensor. I had to force it on, force it to lock, there was no debris inside, and it wasn't the seal causing interference. Had a Delphi connector on hand that fit perfectly, so I know the one fitted is to blame. The single signal wire connector is labeled "IIIB," which I'm assuming is the brand of the installed connectors.The other crimps, wire quality, and seals in the back connector all appeared to be good quality and properly installed. I was disappointed with the poor fitment, but will attempt to use it.

For anyone that has went from manifolds to headers, I definitely would recommend this change. Ignore my crap wiring. I didn't put much effort into it. Wanted to see if it worked first.I have a 93 k1500 I've been building on and I went with hooker ceramic coated long tube headers. My exhaust system flows way better than previously and I stuck with my original single wire o2 that pretty much tells the computer "Hey, I'm an o2 sensor. Run open loop, run closed loop." My issue was that my original o2 was not getting hot enough to tell the computer to run closed loop so it was staying with the default fuel settings and dumping way more gas than it needed to when I was running it. Actually, it got to a point where my truck was blowing straight soot and my spark plugs were about as dark as a haunted house.I installed this and it did great. I do notice a slight positive difference in fuel mileage which is great and it gets the truck into closed loop a lot sooner when warming it up. I'm happy with that. I'm grounding it off the engine and running the positive off a key on source. Running some cataclean in the fuel to help take care of my neglect I previously mentioned.

This item allowed me to switch over from a one wire O2 sensor to a 3 wire in a snap. These work on TBI as well as TPI. The heated 3 wire sensors enable the computer to begin actively metering the air/fuel mixture sooner after a cold start, delivering better, cleaner combustion and gas mileage.

This harness was purchased along with a heated O2 sensor. Simplified the wiring significantly being I was only running a 1 wire O2 sensor. Truck runs much better now.

This worked for me. I used it to replace my 1-wire O2 sensor on my '93 GMC K1500 with a 3-wire heated O2 sensor, ACDelco AFS74. The harness connected just right, and the ends were long enough to connect it to my electrical block on the engine compartment side of the firewall. My truck idles more smoothly now. I don't know if it is because of the heated sensor, or just because the non-heated sensor was old and due for replacement, but it runs better now so I'm happy. I'll post a picture of the old and new O2 sensors, with the harness attached to the new one.

This product is perfect- I don't know what the other reviewer is talking about.My 1988 GMC truck had a 1-wire unheated o2 sensor-- this wiring harness mated PERFECTLY with Walker Products 250-23005 3-wire oxygen sensor (or ACDelco AFS74)-- the connection is waterproof, dustproof, and uses existing 1-wire plug to mate w/ my truck's stock o2 sensor plug. Ground and power wires are plenty long to allow routing away from hot exhaust components and reach several power/ground locations.Would recommend to anyone running older vehicles (like most late 80's-early 90's TBI GM cars and trucks) still using a 1-wire oxygen sensor.

Worked perfectly

Saves time if thats important to you.