i have an 01 cls with alphawerks headers that have been on for about 2 years.....about 6 months after the headers were installed the o2 sensor went bad and the dealer refused to warranty the sensor due to the aftermarket headers....now my car has been acting funny lately(when cruising around 2200 rpms the car seems to lose alll power and almost stall then suddenly come back to life and restoring power to 2200-2500 rpms causing the car to buck because this occurs repeatedly) and i have a cel on so i took the car to the dealer and they are telling me that the o2 sensor is bad again....has anyone experienced similar problems?..are the headers causing the sensor to go bad?...i thought o2 sensors were supposed to last a long time? i only have 60k miles and the first one was replaced at like 40k miles. the service manager told me the headers could be causing the o2 to get too hot...anyone have any input?..

 

Dude, I'm pretty sure I hold the record for the most number of primary oxygen sensors killed among the J32 crowd. I went through 4 in like 40k miles.

It all started after I installed the headers, along with other modifications. Well, actually, I should say it all started when I started modifying the car and road racing it. I had the damnedest time trying to figure out why the sensors were going bad so quickly.

Hopefully your case is the same, but the solution to my problem was tuning. My car was running too rich, and especially under extreme driving conditions (like on a track), the unburned fuel was getting super hot and cooking the sensors.

After I got the V-AFC II tuned, it never happened again. My car was running like in the neighborhood of 10.x to 11.x:1 AFR. Car's now tuned to about 13.8:1 AFR throughout the RPM band. The fuel mileage actually went up slightly (logical, since it's now using less fuel) and the car felt peppier. If you have a moderately modified car with majority or all of the bolt-on's available for the car, then it needs to be tuned. Granted, there are many out there who are fine without it, but it's on a case-by-case basis. Some cars need it, others don't.

Hope that helped. Good luck.

 

thanx for the help but all i have is cai and headers...i cant justify spending the money to tune it

 

You never know, he might be on to something here. The only think he has under the hood that you don't is the TB spacers, cooling mods, and pulleys.

How much do the o2 sensors run?

 

what are you guys tuning on a stock ECU. what can you tune without an extra chip or computer.

 

the o2 sensor runs about 120 i believe...i was wondering if the dealer has any way to tune the car...or if the can reflash the computer with and updated tune...anyone know if the 03's have a different tune?...i still dont understand y its running rich i thought when u increase air flow the car should be leaning out?

 

You increase airflow, and the computer will compensate for it. A lot of times, it'll overcompensate to run safe.

You can buy an OEM sensor from Tim at Ray Laks for a LOT cheaper than 120 bucks. I bought all of mine from him.

"IF" it's the car running too rich, you'll just keep blowing sensors and it'll add up quickly.

Right now, your best bet is to find someone with a wideband o2 sensor and check to see if your car is indeed running rich. You could even go to a shop with a dyno; they almost always have a wideband; you won't have to dyno your car, just ask them to sniff it real quick. Shouldn't cost too much at all.

I know these aren't exactly the easy "go to Autozone and buy this off the shelf" type of solutions, but you could narrow down the cause of the problem by doing this.

Good luck.


jproy -- can't tune a stock ECU. You need V-AFC/V-AFCII or E-manage.

 

I had a high-mileage 91 Civic Si, and later in its life (every 6 months, for 4 years) it would start running rough, was hard to start, and one of the dash [engine] lights would go on. In part, because of emissions testing, I would spray throttlebody/combustion chamber into the TB. I thought that there were probably carbon/oil deposits in the cylinders, and likely on the O2 sensor too: a minute later the car would be running perfectly again, and would for the next 6 months/12,000 km. I would either do this pre-emptively, or when it started to run rough, and it would be fine again for another 6 months after another treatment.

Ultimately, when I exchanged the engine for a lower-mileage alternative, I used the original O2 sensor, then 10 years and 250,000 km old.

 

is it possible the 02 senor is rubbing against the chassi because of slight misalignment of the 02 bung and or excessive movement from bad motor mount/s causing the 02 to rub?

 

its a possibility considering i had to trim my oil pan in order to fit the 02 sensore in the y pipe