my 01 DII has had check engine problem since I got it. The ODBII reader i bought from Autozone says its 02 sensor. So because of the good info here on the forum, I replaced all 4 o2's (Bosch) and also I changed spark plugs @88k. Then the light came back on after reset, says 1/1. So I thought I got a bad sensor and replaced it. Reset computer, and 3 starts later, light comes on again, and says 2/2 o2 is bad.
I think now its not the o2 sensor because it's new, and impossible? to get 2 bad out of 4 new. Does anyone have an idea what else might be throwing it? Some other posts said a MAS sensor? & check the air filter...any other possibilities? I really need to fix this, I'm concerned my MPG is suffering bec of it.

thanks!

 

You need to quit throwing money into something you don't understand.
Exactly what fault codes do you have???????????????????
Are you still running the factory plug wires??

 

You need to replace the plug wires. Mis-fires will set O2 codes every time. When the mis fires get bad enough they will set a mis fire code too.
Dont wait that long.
Replace the plug wires, they are not meant to last more than 60,000 miles or so. Only use Magnecore plug wires or you will be doing the job again in a month or so. You can buy then at www.atlanticbritish.com

 

I'm not sure if the plug wires were ever changed, I bought the Rover with 86k miles.

I just now ordered new plug wires, even if this isn't the problem, I believe new wires are a good idea. After they arrive and I put them on and reset the codes I'll update this thread with more info. thanks guys.

 

What brand of plug wires have you ordered?? Magnacor 8 mm I hope.

 

unfortunately I didnt research the rest of the forum, and I just went to Atlantic as Spike said, and ordered the 7mm Magnecor. Then later after reading more here, I see you (Mike) say do 8mm's. So I tried to ask Atlantic to take back the 7mm because I want 8mm and the person said they will charge me alot for restocking. So i dont know, what should I do ? roverconnection.com is ALOT cheaper than Atlantic too.

 

Just keep the 7mm's. You will be fine.
By the time you pay the restocking fee and then ordering from roverconnection, whos shipping is higher than AB's anyway, it will cost you alot more than you want.
Sorry that I didnt specify the 8mm's.

 

OK, I changed the plug wires, and reset the codes. Check Engine light comes back on after 5 miles, says O2 error 2/2. I'll get the exact error code and post it here.

Any other ideas about my engines problem guys?

 

First off, I buy my Magnecor wires directly from Magnecor, secondly, I've been using the 7 m/m on DIIs for a while now with no problems. The ability to use the OEM looms is worth a lot to me. I do however wish they'd make them an inch longer.

When dealing with DTCs, one must understand the theory of operation of the Engine Management System. In your case, the presence of a DTC indicating an oxygen sensor may or may not mean that it is the sensor, or it could be telling you that there is a condition that is causing the signal from the oxygen sensor to be out of the expected range. If you have real-time readout, sometimes you can detect a "Lazy" sensor. the DEC Super-Scan I just got even has a function to test response of oxygen sensors to assist in ruling out a tired sensor from another condition. Things like misfires and leaking or clogged injectors can cause DTCs to be logged for oxygen sensor problems. MAF sensor problems usually manifest themselves as A/F ratio problems or an indication that the ECU has modified the fueling to the maximum it is able, either rich or lean, depending upon the underlying ocndition.

It has been said for years that the most commonly replaced correctly functioning component is the oxygen sensor. I have received dead sensors, right out of the box when buying from Napa. I haven't bought an OEM sensor in years and can't comment on that.

Lastly, it is also VERY common for generic OBD-II code readers to give non-sensical responses when hooked up to Rovers. I love it when folks come to me and tell me that Autozone told them their truck needed and EGR valve and would I put one on their truck! I have a standing offer of a million dollars for the first person who can find an NAS Rover V-8 with an eGR valve! They don't have them! (yes, I know some of the diesels do).

PT

 

What is the exact fault code you had before and after the wires were installed.