I would just like to mention I have the 2.8, not the 1.8 so my 02 sensors are located right after the exhaust manifold and then another two between the flex pipes and the cats.

That's why I was asking. Apparently it is different in the turbo models.

 

Nope, pretty much the same setup. It's mostly universal on all cars since the early 80's. The only difference is there's a turbo after the manifold and before the first O2 sensor on the 1.8T. Oh, and there's only one exhaust manifold.

 

The systems are similar but the secondary 02 sensor positions are different in my 2.8 and in your 1.8.

Closed case.

 

No they're not. Second O2 sensor is after the cat and before the flex pipe. Same as yours.

 

Technically you're wrong since the cats are go after the flex pipes on a 2.8, but that's just semantics and means nothing. The thing is, if done properly an O2 sensor delete doesn't need the sensor plugged in at all, the fact that you're getting a code means it was done wrong. What code do you get from unplugging it? My guess is it relates to the heater, so maybe try unplugging/snipping the wires that don't go to the heater just to prevent the open circuit code as a temporary measure until you get the software issue sorted.

Kamil, you're both wrong and right. There are 2 styles of 2.8 downpipes, one with a precat and one without. If there's a precat the second O2 sensor goes after it but before the main cat, if there isn't one it goes after the only cat. Side effect of this is you can do whatever you want with the main cat without triggering a code if your car has precats since only the precats are monitored.

 

Oh right, good call. I forgot the cats were farther downstream on the 2.8. But yes, makes no difference where the flex pipe is. It's the O2 sensor position relative to the first cat(s) that matters.

I believe the code was P1118, which is indeed a sensor heater error. I tried snipping the signal wires (3 and 4) and leaving the heater wires in place (1 and 2). While that did not turn on the engine light, it did generate an error code which was stored in the ECM at all times... P0190, no signal from second O2 sensor.

The ECM is back at the tuning shop to have the issue resolved, so the car's undriveable for the week anyways.

 

Now that you mention it I must have those precats in that case because the sensor is like you said in between the precats and the cat itself.

 

Thank goodness for the simplicity of the 1.8T,especially since I got rid of the secondary air injection system.