Long term fuel trim +25% on Bank 2, +13% on Bank 1 and 6.9 MPG…
 

Hi,

I have a 2000 Disco 2 with 2" lift and 32" AT tires. It seemed that the fuel consumption was high at 9 to 10 MPG in the city but I thought it’s the lift and tires but 6.9 MPG is ridiculous. I connected my OBD scanner and the long term fuel trim on Bank 2 is +25% and +13% on Bank 1 which I think is wrong. However no fault codes pop up. MAF showed 5,7g/s on idle and over 25 g/s when reved up. The car has new plugs and cables, bought at a Land Rover store. Apart from the extremly low MPG the car runs fine. When started cold it seemed rich (dark smoke when reved up). One mechanic said that car's vacuum level is too high on idle, app. 0.45 and then goes down to app. 0.3 and but I don't really see the connection.


Is it the O2 sensors or should I look for something else? The seem to be working in the right range, i.e. 0.05 V to 0.7V. The car has 120k miles on and I have no idea if the sensors have ever been changed.


Thank you for any ideas.

With 120K, have you done the 60K? Cleaned the induction system? Seafoamed the Disco?

Many feel you should replace all four O2 sensors every 60K. Others just the upstream sensors. What is strange is that you are not setting the light, but your gas mileage is screaming you have an issue.

Look at the Sticky's at the top of the Discovery II section. If you have the cash, replacing the 02 sensor certainly isn't going to hurt. I got last O2 sensor from Atlantic-British.

www.roverparts.com

RS

Are you using premium gas?
I would replace the front O2's and go from there, not using premium will lower your MPG.

are you the original owner? let me tell you a story lol... i bought mine with no SEL on, low and behold i could not figure out why the heck i was getting terrible fuel economy 200km a tank at a 100 bucks. I had no scan tool at the time.. yah.. well when i got mine, plugged it in and i had about 20 codes... Since the SEL is an LED which can't be replaced or taken out with out damage, i took the dash apart and come to find black tape folded up and pressed in front of the l.e.d. ffs. Well i began down a long list of suffering.. I changed just my front O2 sensors reset/unplug the battery for bit and reset the codes and immediately got 400kms to the tank... wow, next is MAF, did the plugs and wires and coil pack (what a job that was) good luck.

I agree with 04roverse above as I had the same experience, it is very common. The previous owner had taken the time to dismantle the dash and instrument cluster to tape over the various warning lights. Funny thing was once i discovered this, the fix was to replace o2 sensor and shuttle valve switch, which was easier then it was to dismantle the dash and remove the tape hiding the lights.

When you turn on the ignition the check engine light, abs, HDC, TC lights should all illuminate briefly, if they do not they have been taped over

would be easier for the sales person to just tell us they are bamboozling us..

If you have a good scan tool you can reset the "learned" fuel trims. 25% extra fuel means something is out of whack, but first reset the trim and see if it works back to 25% from 0%.

Old front O2 sensors could easily be the problem and need replacing.

That being said, 25% extra fuel won't give you 6.9mpg.

When you next change your oil check for small slivers of metal from mashed up rod or main bearings because they could easily be throwing things off.

The original post is from 2011...and the poster hasn't been on since then...doubt he's still looking for an answer...lol.

lol, well I think i'm so frustrated i don't even care lol

look at this link;


what is happening here.. can this really be from aftermarket O2 sensors?