Bustedback

Never use this option, always spring for the O2 sensor with the connector already on it. My co-worker cheaped out and used the DIY O2 without the connector, it cost him $1500 for new cats on his Cheby.

beavervango

what did it do to friends ride, besides ultimately new cat. the one i got was a direct swap except had to splice wire for wire. no probs, but runs way better.

Bustedback

I'm not sure what the deal was, but he must have put the connector on wrong and it cause the engine to run way too rich and destroyed the cats.

eggdashure

Any idea what this is doing to "clean" the sensor? Is it putting the engine into a lean mode, rich mode? Since I Seafoam every few months I'm guessing mine is fairly dirty.

crystalion

Why would you think its an O2 sensor when there are dozens of things that will cause bad gas milage, the O2 not being first choice.

If through your driving and repairing your jeep you have narrowed your search to the O2 sensor then fine--Buy a brand new one don't even bother to try and clean it.
Search the web I have had "O2" quotes from $ 50.00- 100.00 for the same exact part. Always buy OEM replacement -makes everything easier-faster and RIGHT.

Bustedback

It really cleans out the cat more than the O2 sensor. The high RPMs and lean mixture gets the cat good and hot which burns out all of the built up carbon and soot. It works, I've done it with my 95 ZJ when it was hooked up to a five gas analyzer and seen the difference in HCs coming out of the tailpipe.

weebur

Here's an article on testing O2 sensors: http://wiki.answers.com/Q/How_do_you...h_a_volt_meter

Alex97XJ

my 1997 cherokee does have 2 bad O2 sensors, would this also cause the engine to missfire, or run alittle rough?? Thank you!

Radi

The front one sure will. The after-cat sensor is only there to monitor the cat.

Cobradwight

Thats why your mpg is bad..95 is a no no for mpg. Leave earlier or plan better routes and drive 65 on fwy.

Alex97XJ

Hey , thanks alot for the quick reply!! This is a big help!!

xj guy

Are both 02 sensors the same? As in If I bought one I could put it up or downstream?

Just had my cat replaced by the dealership. looked underneath and there was nothing from the cat back (ordering new kit from performance curve). But I'm debating buying new O2 sensors as well. Should I just buy one and throw it in up top?

The Rooster

yes buy upstream and down stream o2 sensors... if they have never been changed... you should have 2 o2 sensors being a 96....

The Rooster

Replace both not just one... if your Jeep has over 100k on it they are most likely both on there way out... the Rear o2 is just as important fyi
and yes it can cause a rough idle or misfire... the o2 sensors control fuel mixture

The Rooster

here is a good o2 sensor read
~~~~~~~~

Upstream Oxygen Sensor Goal Voltage
From Star Center News #5, February 2000 - tests for those who have access to OBD II or OBD III code readers.

Since the introduction of OBDII with both upstream and downstream O2 sensors, the downstream O2 sensor has been used to evaluate catalytic converter operation and to control converter efficiency.

When looking at the upstream goal voltage, it should fluctuate above and below the normal center (.4 to .6 volts) based upon what the downstream O2 sensor is reading. The vehicle should be driven through all speed ranges when checking goal voltage. If the goal stays high or low all the time, a thorough check of the downstream oxygen sensor should be made. Be sure you check the sensor, wiring harness, connectors, catalytic converter, and inspect for exhaust leaks.

Although a CEL may not be illuminated, there are instances when the downstream O2 sensor goal voltage is out of range, causing driveability problems or low fuel economy.

If the downstream O2 sensor tends to stay below center all the time, the PCM will adjust the goal voltage higher in an effort to correct the low O2 readings of the downstream sensor. This can result in low fuel mileage.

If the downstream O2 sensor has a tendency to stay above center, the PCM will set a low goal voltage which results in a lean fuel mix which can cause the engine to run hotter and aggravate a spark knock condition.

Sometimes a service technician will reset the PCM and take it for a test drive. The PCM does a recalibration after the reset, and the problem may go away until the PCM has completed a relearn of the system and then begins to attempt to correct for the downstream sensor error. If the symptoms reappear after several days of driving after a service is performed, check the downstream O2 sensor, the exhaust system, the wiring, and the catalytic converter. Note: a worn out catalytic converter can produce symptoms similar to a bad downstream O2 sensor.