1 wire to 3 wire O2 Sensor

[tayto]

tayto.... Can you post up a few images of how you spliced into the gray wire?


Trying to figure out the best way to run this.

I don't have pictures but these days I generally use the non-insulated butt splices with the "good" heat shrink that has glue in it. https://www.grote.com/electrical-co...inals-connectors/uninsulated-butt-connectors/

as far as location, i do it all by the fuel pump relay.

 

[JCribb]

So you've already replaced the catalyst, and it still has "rich"-smelling exhaust? Apparently, you've cooked the new cat.

If I had a cat to cook, I’d understand, but it magically disappeared like my ex wife’s faithfulness.

It’s the tbi rich smell I’ve smelled from every tbi truck I’ve seen.

 

[tayto]

If I had a cat to cook, I’d understand, but it magically disappeared like my ex wife’s faithfulness.

It’s the tbi rich smell I’ve smelled from every tbi truck I’ve seen.

had this recently on a friends "de-cated" truck. the thermostat was stuck open so the engine would never get up to temp. smelled real gassy. i'd also look at replacing the CTS, it is almost a tuneup thing like a 3 wire o2....

 

[Schurkey]

If I had a cat to cook, I’d understand, but it magically disappeared like my ex wife’s faithfulness.

It’s the tbi rich smell I’ve smelled from every tbi truck I’ve seen.

Time to acknowledge an inconvenient (to some folks) truth:
Rich "smell" does not always indicate an actual rich mixture.

ALL engines push hydrocarbon emissions into the exhaust manifold, and from there downstream. That's WHY there's a catalyst--to reduce the HC emissions into water vapor and CO2.

No catalyst, or a failing catalyst = more HC emissions than folks are used to. Which makes them think the engine is "too rich".

WHAT DOES THE OXYGEN SENSOR SAY? Assuming the O2 sensor is working properly, that is the judge of "too rich" or "too lean".

No catalyst? Of course it "smells rich". And if you're getting that smell from other TBI vehicles, all I can say is that the newest of them is twenty-plus years old, they've probably got failing catalysts, too.

had this recently on a friends "de-cated" truck. the thermostat was stuck open so the engine would never get up to temp. smelled real gassy.

Absolutely. A failing CTS that shows too-low temperature, or a failed thermostat that causes too-low temperatures can drive the mixture pig-rich, set codes, cause all sorts of trouble...

i'd also look at replacing the CTS, it is almost a tuneup thing like a 3 wire o2....

...but on the whole, I'd rather have a functioning OEM CTS than a cheap-junk aftermarket CTS.

In my driveway, if the CTS (and most other sensors) isn't showing a fault, I leave it alone rather than replace it as preventative maintenance. MAF sensors, and O2 sensors are something of an exception to that.

 

[uhhhpooo]

You don't need to cut the connector with this setup.

www.amazon.com/ACDelco-AFS74-Original-Equipment-Heated/dp/B000C9VTRC/ref=sr_1_3?dchild=1&keywords=acdelco+afs74&qid=1634063397&sr=8-3

www.amazon.com/Michigan-Motorsports-Heated-Harness-Adapter/dp/B0141VHZ6U/ref=sr_1_1?dchild=1&keywords=michigan+motorsports+22300&qid=1634063344&sr=8-1

how did you wire it? looking to do the same thing wasn’t sure where to wire it to

 

[PlayingWithTBI]

how did you wire it? looking to do the same thing wasn’t sure where to wire it to

The ground wire can go pretty much anywhere, I mounted it on the left fender well with a Tech screw (self tapper). I already had a switched source from the ignition switch but, some people have wired it to the fuel pump power feed. Really, any switched lead will work, it doesn't draw that much, or wire in your own relay to the battery.

 

[uhhhpooo]

The ground wire can go pretty much anywhere, I mounted it on the left fender well with a Tech screw (self tapper). I already had a switched source from the ignition switch but, some people have wired it to the fuel pump power feed. Really, any switched lead will work, it doesn't draw that much, or wire in your own relay to the battery.

so just splice into the gray(i think) wire on the fuel pump relay

 

[tayto]

so just splice into the gray(i think) wire on the fuel pump relay

you want the side of the relay that is not hot unless the engine is running. theres a ground bolt right by the relays, usually used for the underhood light ground. this is what I use for 3 wire o2.

 

[uhhhpooo]

you want the side of the relay that is not hot unless the engine is running. theres a ground bolt right by the relays, usually used for the underhood light ground. this is what I use for 3 wire o2.

sounds good thanks