I have a 2000 LR Discovery II that has had the SES light on for a year. Was told that I needed new cats. Had the cats changed, both OEM and used from another Disco2, but the problem remains. Engine is running very rich to the point that getting less than 10 mpg. Vehicle has 310k miles, but other than the cats and O2 issue, it's unbelievably a fine car. Can anyone help? Thank you in advance.

 

As much as I miss Cali, I don't miss the smog regulations. Any engine codes? How's your MAF? (I have zero experience, just thinking about things that regulate fuel injection...)

 

Tune up (plugs and wires), premium fuel not from Joe's Gas and Groceries but from a name brand, like Shell, Mobil, etc.
New front O2 sensors, clean air filter, reset the check engine light, drive for a tank of gas, fill back up with premium and add this, and once you hit half a tank take it to be tested.

 

Thanks a bunch. Will definitely try your suggestion. Already spent enough with the stealer to buy a used sub-compact trying to get this fixed.
Will also get codes to post in the event someone has seen this problem before. Again, thanks.

 

If you have codes for both left and right upstream O2 sensors, look for vacuum leaks or a bad MAF before you move on to cats and new O2 sensors.

 

Why did you drive with the SEL on for a year, it was on for a reason and you could have saved the cats if you had the codes read that were causing the problem.
So how about getting us the fault code numbers so we can help you with your problem.

 

To answer your questions Mike, after paying the dealer, then a dealer moonlighting mechanic, then an independent service shop to fix the problem and none were successful, I'm broke!

The codes are: P0161, P0130, P0154, P0139, P0171, P0140, P0141, P1174, P1171
Thanks guys. Really appreciate you taking the time to think about this.

 

yeah but the codes have to do with the oxygen sensors not the cats. Did they repair anything or did you pay somebody to put the cats in.

 

All that to me says air metering issue. Either unmetered air is entering after the MAF, or the MAF itself is bad.

Check all of the seals and clamps from the airbox to the upper intake, and also check for vacuum leaks. If you can confirm that there are no vacuum leaks, then the next likely candidate is a dirty or failing/ failed MAF.

On cleaning the MAF, follow these instructions:
Discovery 2: MAF cleaning instructions - 4x4 Community Forum

Using this MAF cleaning spray:


MAKE SURE YOU ONLY USE MAF CLEANING SPRAY AND NOTHING ELSE or you will likely ruin your MAF.

 

Those are 02 codes which are causing some lean or rich codes, by the way, you can be running both lean and rich as the 1171 and 1174 codes indicate. Need to deal with the 02's, then clear the codes and see what is left.