black2000xj

factory sensors are NTK right? need a new upstream and im seeing bosch, denso, and ntk...i want oem

I think running seafoam thru my jeep ruined my os sensor
it has been running rough at times and my mpg dropped by 3 or so

CCKen

Yes, NTK is the OEM O2S.

I worked on a Ford Escort for my Son's girl friend. It was a basket case.

Ran some Seafoam through the motor and it immediately put on the CEL. Checked it with my scanner and it showed an upstream O2S fault. I ran the engine for awhile and it cleaned up the O2S...luckily.

I won't use Seafoam on my 4.0.

If you are going to replace your upstream O2S, I suggest you change the downstream as well, especially if you are seeing poor gas mileage.

black2000xj

i replaced the upstream about 6 months ago...then 4 months ago i ran seafoam and it brought my jeep down...no cel...but shaky idle and mpg loss...im thinking its the upstream one is shot from seafoam

i didnt at the time replace downstream one....i was told that dont have any effect of mpg....

I love rock auto for parts...half price of napa even when i have shipping...
i ordered ntk for oem ...cant wait to get it

CCKen

This is one of those Jeep myths that just keeps on ticking. It does affect mpg.

black2000xj

i was told multiple times its only to make sure the cat is working properly...the upstream does a/f ratios

downstream is just to make sure the cat is doing what its suppose to do...and it would affect mpg - as its after the cat

CCKen

Here's some reading for you about O2S goal voltage and the downstream O2S. It was taken from a Dodge Ram website.

Do what you feel is best concerning your downstream O2S. I'm certainly not going to twist your arm.

If you feel comfortable with this data you can re-educate those multiple people who told you "its only to make sure the cat is working properly", or "downstream is just to make sure the cat is doing what its suppose to do" [what ever that is? LOL]

~~~~~~~~

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.

The Rooster

That's a good read ken thanks for the info I couldn't find anything like that

black2000xj

x2

will order a downstream sensor here in a minute

muhib 96 country xj

P0135
• Generic - O2 Sensor Heater Circuit: Bank 1 Sensor 1

P0132
•Generic - O2 Sensor Circuit High Voltage: Bank 1 Sensor 1

P0132
•Land Rover - Oxygen Sensor High Voltage *Codes* A U

P0141
•Generic - O2 Sensor Heater Circuit: Bank 1 Sensor 2

P0138
•Generic - O2 Sensor Circuit High Voltage: Bank 1 Sensor 2

P0138
•Land Rover - Oxygen Sensor High Voltage *Codes* A D

Ok my obd scanner tells me above mentioned faults. I just bought this cherokee 96 country xj. And my check engine light is on.
Can anyone help and guide me how to fix these o2 sensors and i am guessing previous owner has put in land rover sensors instead. Pls guide me which are the right ones. And where these are placed? and which brand should i go for? Links of diagrams would really help. Thank You!

black2000xj

go to rockauto.com. select your make, model, year, motor as the computer tells you.
click emmisions
02 sensor

ntk is the factory one...order 1 upstream, and 1 down stream

write down the product number for the upstream one, that way you dont mix them up some how

They are "plug and play"....just unplug the old one, screw it out , put the new one in and hook it up

i did both of mine this past weekend...jeep runs 100% better. I didnt have a cel light one either...

im curious to see how much my mpg goes up. I keep a eye on it every fill up...ever since i did seafoam my mpg went down. I think it ruined my 02 sensor with junk....b/c my 4.0 is very "peppy" now...not to mention it got rid of that shake when sitting at a red light or stop sign

c'mon mpgs! your the only downfall to jeeps!

70hemicuda

Exactly what happened to my jeep. Did the seafoam. Ran great for a while then complete ****. Rough idle and bad mpgs. Just ordered new o2s so hopefully that clears it up

muhib 96 country xj

Black2000xj

Brilliant! Will get on it asap! And will let u guys know about the results. Thank you!

Muaddib420

Well glad I never sea foamed my intake LOL.