Pulling my hair out (what little I have left) guys!!!

I have now reset the light and/or codes 5 or 6 times at Advanced. Each time, I do something else. I found a missing exhaust manifold to down pipe stud and nut, and the other fasteners there were not as tight as they should be.....replaced and tightened them all. (passenger side cylinder bank............is that bank 1??)

Had the codes reset, same result as above, malfunction on O2 sensor1, bank1 and system lean.

So,...yesterday,...I figured, screw it, just spring for the O2 sensor. Replaced it today with a proper Bosch sensor with the OE molded connector ($75 at Autozone)...........and after 10 minutes,....it came back on while sitting at a light.

Had the codes checked again.............same thing............."sensor 1 bank 1 malfunction". and,...."System running lean" (bank 1)

Please help if you can.............I really am running out of ideas and have no idea what to do now.

Brian

 

So what have you done to the truck so far? How does it run? Smooth, rough?

 

in answer to your query....what have I done.....Im going to ask you to re-read my initial post....cause it tells you what I have done thus far.

After replacing the 02 sensor today.....I thought that the idle which is usually very rough was smoother....light came on immediately after the idle stumbled a bit for a few seconds at a stop light. Truck drives great otherwise but only get 9.6 miles per gallon in town playing with the gas pedal......hey, its a V8,....I want to hear that baby roar a bit.

 

So all you have done to it so far is replace one O2 sensor. If youhave another thread I do not know where it is, sorry.
You must replace all the O2's at the same time.
When was the last time you replaced the plugs and wires? Bad plugs and wires can set off O2 codes and cause bad MPG.
If it runs rough at idle that is a classic sign of bad plugs and wires.

 

YOu need to replace all 4 sensors at the same time and have your performance memory reset by someone with a Rover scanner. You can wait for the truck to "see" the new sensors, but it is faster with the reset.

Follow the sesor wires all the way up. That sensor is the most likely to lay over on a cat and mess up the wires. Make real sure that you don't have an exhaust leak at the manifold still, and that your cat is ok. Bang it with a rubber mallet, if it rattles, it is bad.

 

That is BS. You do not need to replace all sensors. Also, bad plugs and wires will set misfire faults. Is it P0130 and P0171? Have a
shop smoke test your intake system and pay attention to the throttle shaft. I had this issue with a customers' disco II and after much debaucle, found the throttle shaft had a vacuum leak that could not be detected through artificial enrichment.

-Kyle

 

Brian,
How many miles on your truck, when was the last tune up done, what was done and what parts were used? What year and model Disco are you driving?

Contray to our new members beliefs, if you are at 100,000 or higher all 4 02 sensors shopuld be changed at the same time.

 

Mike is right, replace all four at the same time. But....I just pulled the paperwork and like I said in the earlier posting, I replaced $450 worth of parts before we replaced the $90 evap sensor and that fixed it. On the Landrover, and I know this doesn't make sense, but the computer is only telling you what it is getting back from the sensors, and there are multiple conditions that can make the computer think something else is happening. I had my system "smoked" also and there were no leaks. That was the last thing we did before we replaced the evap sensor. It's located on top of the engine on the driver's side.

Forgot to add that I did replace the wires and plugs at the same time we did the evap sensor, I don't know if that helped the light being on but it did run better......

 

Mike and other respondents,

2002 Disco II 4.0 Last big service was 60K. Doesnt look like plug wires have been changed as they show cracking at each plug end.

Still just 78K on it, The state inspection is out now.....so cant drive it legally any more,....So,...I've gone back to driving my good old dependable 213,000 mile 95 Montero that never breaks.....that I thought I was replacing and doing an "upgrade" on when I bought the 2002 discovery.

I didn't take note of the code number this time unfortunately. after finding the missing exhaust stud, along with the other fasteners being loose at the Manifold/downpipe .............I replaced the missing stud and tightened all the other fasteners,...had the codes cleared at Advanced (5th or 6th timethey are getting tired of seeing me) ......and when it appeared to be holding OK.....I took it over for a state inspection..............it flunked again.............his message also pointed to sensor one, bank one..............stating it was "Not Ready"...............so................I figured.........screw it and replaced that particular sensor since every code reading so far has been consistent and pointed to Sensor one,...bank one...... had the codes cleared again..............but...the light came right back on 5 minutes later...........still showing sensor one, bank one.................and also.................the System lean message.

I've been unemployed for a year..........living on credit now....cant afford to spend $300 on four 02 sensors on a hunch that that might cure it............when it might end up being the MAF, or..............vacuum leak,............or............bad exhaust gasket??????................Also have 3 of my 4 doors torn down for broken window regulators and door lock actuators...................this damn thing is eating my lunch big time.............
Brian

 

You may know that bank one sensor one is the driver side (US)
before the cat 02 sensor.

There is a Austin Land Rover club and I bet that they have someone
that may help with a hands on look.
Look under Texas Rovers.