02spas2k

do they make an aftermarket 02 sensor that goes in the header (NOT THE CAT) im pretty sure mine has crapped out and i need a new one. i was wondering if there is a better one out there over the stock.

my car (its supercharged) runs awesome when it is warmed up but after some driving for maybe a half hour it starts to run like shit. very sluggish and sets PO171 lean mixture code. would this even be an o2 sensor problem. Fuel pressure is fine.

thanks

MAtt

Malu59RT

TTT, looking for the same thing.

Road Rage

The O2 sensor would not cause a lean condition -mif anything, a bad reading from it would likely cause the engine to go into a fail mode map, which usually enriches to protect the engine.

There is no perf gain of one O2 sensor over another - your problem is mods-related in my opinion, and you need a good dyno map of A/F as a start.

cbender

I'm not sure why you'd want to replace either of the stock sensors with another narrow-band one. The stock ones work in their current location, for what they're designed to do, and I doubt that the stock ECU would do anything other than freak out if you moved it. Besides, mounting a sensor in the header will burn it out -- even the aftermarket widebands mount in the downpipe, away from the immediate heat of the exhaust flow.

I suspect your s/c problems aren't related to the sensors. Do you have some sort of fuel tuning device -- VAFC and rising rate FMU? What are you using to prevent the ECU from seeing boost? Those are far more likely to be the cultprits than the sensor itself.

Note that the rear O2 sensor will not trigger any conservative engine algorythms if it throws a CEL, as it's ONLY purpose is to support OBD-II. Put another way, the CEL generated from the rear O2 sensor is really only to indicate that the CAT is malfunctioning, but the ECU relies strictly on the front sensor for adjusting short term (and, ultimately, long term) fuel trim.

CB

02spas2k

i have a Comptech kit and from what i have read, it should run fine with everything that comes with the kit. It was running great up until about 2,500 miles. i also searched and found that people have had problems with there 02 sensors. i just wanted to know if there are better 02 sensors to last longer or even run better because i am going to replace them.

thanks

MAtt

Prolene

I see Bosch now has parts numbers for S2000 sensors. That might be cheaper than Honda but probably at least as good.

cbender

I'd call Comptech and talk with them about this. My guess is that the part itself is made by all of one or two manufacturers worldwide so it won't be the case that you'll find much variation between what you're able to buy. That's just a guess, but I really don't think the O2 sensor is the cause of your problem. I ran the stock O2 sensor on race gas for a while without any problems, before I switched to a wideband with the EMS, and the character of my exhaust stream with the turbo is likely to be no closer to stock than yours with the s/c.

CB

Malu59RT

I'm having a problem with my primary O2 sensor reading overly rich conditions at all times, even though we had it on the dyno with a wideband showing the A/F was around 11.5:1 I'm guessing that running the car overly rich for about a week before final tuning, and lots of smoke from my bad turbo has fried my primary O2 sensor. I don't have a standalone, and am running the Emanage, so I thought it would be good to replace the O2. Should I not bother getting a new primary O2?

Jason

cbender

First off, there's almost always a difference between the dyno reading and what the car's sensor is reading simply b/c of where it's placed in the exhaust stream. Second, if you've still got the stock sensor, it's essentially useless for measuring your air-fuel ratio except under cruising conditions, as the reaction time isn't fast enough. Given those two factors, it's hard to know whether your O2 sensor is actually reading "overly rich" or you were running (and continue to run) overly rich.

In any case, while I'm slow to take a stand on mods until I have direct experience with them, I will say that you'd be a fool not to spend the money for a wideband. AEM sells one for about $400 without a display provided that eManage can read the input from it. Otherwise, buy a stand-alone wideband with a display so you can at least see your air-fuel ratios. It is, by far, the most important tool you can have for knowing whether or not you're putting your engine at risk.

Tune all you want, but as soon as conditions (temperature, etc.) change or as soon as you start driving under real world conditions (with lots of partial throttle, into boost, out of boost, transitions) and your air-fuel ratios will deviate from what you got on the dyno.

As for replacing the front O2 sensor, I think you'll have to if, in fact, its fouled. The stock ECU (which you still have) is gong to insist on getting correct readings or your short (and ultimately your long) term fuel trim is going to go to sh^%$t.

CB

__________________
C. Bender
2001 S2K Silver/Black
AEM EMS, Fuel Pressure Regulator, and Wideband O2 Sensor; RC Engineering 550 Injectors; Turbonetics TO4B 60:1 Ball Bearing Turbo; Tial 46mm Wastegate and 50mm Blowoff Valve; GReddy EGT and Boost Warning Gauges; Upgraded Intake Fuel Pump; Oil Filter Relocation Kit with Stainless Steel Lines; Speedcraft Front Mounted Intercooler, Mandrel Bent Tubing, 3" Down Pipe, and 3" Stainless Exhaust; A'PEXi N1 Mufflers; Clutchmaster Stage 3 Clutch; Toda Lightweight Flywheel; Mugen Radiator Cap, Thermostat, and Fan Switch; Upgraded Oil Bolts; Spoon X-Brace; HeCash Brake Ducting; Competch Stainless Steel Brake Lines; WorkMeister S2R 18" Wheels; Lucid's Front and Rear Speakers; 2002 Stereo Head Unit; Rick's Front Badge; JDM Clear Side Markers; Muz Shift Knob; Uber Cool Nurburgring Decal