DEIGER

Model year 2002, 30K miles, and an easy driver. Installed a Vortech, Mugen Header, and Spugen Dual TI. Threw a CEL, had it checked and O2 sensor came up. Had it reset and CEL came back about 1 hour later.

1)Will this setup blow out the cat or is it that the sensor just went bad?

2)Also how will the cat. hold up with FI?

3)I might go back to OEM exhaust due to being too loud; will this improve the cat. situation? (Thought here is that the Mugen and the Spugen are leaning up the engine that the cat. will heat up abnormally, OEM might stop this?) (Vortech brought this up when I called them about)

Thanks in advance for the input!

Deiger

duff0000

https://www.s2ki.com/forums/index.php?showtopic=229959 that mod might solve your problem.

xviper

1. How do you know it's the O2 in the cat? What was the exact code? It could be the one in the header. It could be the sensor itself, the heating circuit for the sensor or a bad wire to or from the ECU.

2. Many, many owners with F.I. continue to use the cat without issue.

3. If the sensor has been damaged already, going back to OEM won't fix it. If "leaning out" is happening, the cat is the LAST of your concerns. A lean running F.I. engine is not destined to live long in this world. A NA S2000 can run lean during a lot of it's operating time with no ill affects to the cat.

PS. That "mechanical O2 simulator" is only for a car with a test pipe (cat-less). This will not likely help you since you still have your cat on. Something else is wrong here.

Slows2k

You really need the specific DTC before going any further. There are multipe "02" sensor codes, with multiple causes.

davepk

Chances are its a secondary O2 heater code. This is a common problem with FI. The first of the two cat cores in the cat becomes dislodged and then proceed to damage the secondary O2 sensor. If you simply replace the sensor the still loose core will damage the new sensor. My suggestion is to get a test pipe and fit a mechanical O2 simulator to it.

DEIGER

Thanks for the replies. The code that came up was P0138 (AutoZone read the code and their machine indicated that code was for the 02 sensor).

Is it possible that the mugen header is making the car run leaner than the Vortech by itself (I am still using the stock Vortech ecu)? Again this was brought up by the people at Vortech.

If at all possible I would like to keep the cat. I may be relocating to a state that has emissions testing (Florida eliminated emissions testing several years back) and don't want to suffer the expense of fines for no cat.

Thanks!

Deiger

Slows2k

The secondary 02 heater failure would be a P0141. A P0138 is high voltage output from the secondary sensor.

This is usually caused by a "lazy" 02 sensor. The troubleshooting involves checking all the wiring to the sensor and PCM. As well as graphing the output voltage with a Scan tool.

As far as the header causing the DTC, I don't think so. I ran a Toda header for over a year SC'd with no DTC's, but it did run lean.

If the output volts are above .8V for more than 4 seconds, then 02 is hosed. You'll need an 02. I'd check the catalyst for having a loose core when you pull out the sensor. If the end of the sensor is damaged, you'll be needed a convertor as well.