Well my problem is a kindof bog but only between roughly 3500 and 4500 rpm.

The history of this could have started last year, and now overlapped to other issues, I'm not sure. Last year around this time I had swapped out my 2.0 ecu for a 1.8, and it ran like a champ. I did get an evap code however, but at least 2 months later. At that time I had a horrible exhaust leak and I was thinking the two were related.

After that I returned home and installed my new header and 1.8 cam. During the process my o2 sensors were seized into my olde header. I replaced them as well. All said and done before I did that work I had a code, and after I had two different codes.

Now I've been running around with 2 o2 sensor codes both relating too my first sensor. I installed that sensor in runner # 3, and the other at the end of the header right before my cat. My previous header, even though the quality was terrible, was also setup this way from a local ( trustworthy) exhaust shop.

I have asked around for opinions on what this could be and have got everything under the sun for answers. Lately all I have done is replace my tps with a brand one and an oil change.

So my question is guys what do I look at next?

My thought was the primary o2 must be shot, but I find it weird that I got the codes the same day I replaced everything. I have reset my ecu many times over and the codes do go away for roughly a 1/2 hour of driving.

My set up engine wise is: the 1.8 ecu/ cam, aem cai, 4-1 shark racing header, 2.5 inch exhaust, and upgraded small parts (oil, plugs etc).

Any thoughts?

Thanks for reading,

 

Is the first sensor a universal one you had to wire in yourself, or a direct replacement part from Hyundai?

O2 sensors have multiple wiring setups. Depending on the year of your car/color of wires on your sensor, there are several ways they are wired. If I recall right, there are four or five different setups.

So I'd say:

The sensor you bought was dead.
The sensor you bought clips in to the wiring harness fine, but is the improper one.


If you wired it yourself:

You wired it wrong.

 

Hmm very possible, the first inline is a Bosch and second is a NGK. Both I bought from Auto Parts Extra ( like a NAPA). The did both plug in very easily.

I was thinking that maybe I bought the wrong 1.8 ecu, as I didn't check the serial number on it before I put it in. I did buy it from this site and a trustworthy seller.

 

BUMP! Nobody has any input here? Anybody think it might be a spark issue? Lol

 

like many parts for our cars (belts, oil filter) the OEM O2 sensors have a reputation for being better than aftermarket from the parts store.

 

^agree fully!! although it works on my dad's elantra, i would just go buy OEM o2 sensors. it sounds like my problem on my low end.

first you need to give us the exact codes before anything.

 

P 0 135 - O2 heater circuit- Bank 1 sensor 1
P 0 131- O2 Circuit low voltage- Bank 1 sensor 1

Those are the codes, I had them up in a previous thread. Anyways I'll give it a go with the genuine o2 sensors and see what happens.

Thanks for the answers all!

 

sounds like a plan. Most likely you've got wires reversed.

There's 2 circuits in a Heated Oxygen sensor. There's the Heater and the Oxygen sensor.

 

yep those are the codes for the wiring for the pre-cat sensor (first, before catalytic). check the wiring all thoroughly. look up the wiring schematic on here. someone else is having the same issue and i posted both diagrams on there. if it's stock O2 wiring, you have to check the connection, the terminals, anything for wear and tear.

not sure what else it could be. there's also the myth that Bosch has two wires reversed on a handful of their sensors. i used one and it is ok, but other people reported problems. still, always use factory.

hope that give some insight.