Cat Bank 1 below efficiency
 

Following on from my fault code thread in the VCDS forum, the other morning whilst the engine was still cold I needed to pull out into heavy traffic so with a gap big enough I gave it a few beans to join the flow from a stop. Result, the engine light came on but the car continued to drive fine. I drove another 60 miles since, and the car still feels fine and using no more fuel than usual and engine light still on.

Moving on to today, whilst at the garage having the rear springs changed the mechanic scanned the car and the fault was "Cat bank 1 below efficiency - Intermittent". Cleared the fault, engine light now out and not returned.

He reckoned that maybe because the engine was still cold and running with cold mixture maybe that caused the light to come on.

Looks like my cats are getting old and less efficient at doing their job. I'll get a better picture in a few weeks as I need to get the car through an MOT.

just to let you know that for the cell/engine management light to come on and tell you the cat or cats are below threshold the margin is only 6% so your cats may well be working 94% fine and its only the 6%that makes the light come on usually you can cure this by putting 1 liter of laquer thinners that a body shop would use, put that in you tank with only quater of a tank of fuel not a full tank, this will get rid of any crap in the cat and carbon off the lambda sensors, there is a product called cataclean http://www.google.co.uk/products/cat...ed=0CFsQ8wIwAA

but this is infact bottled up celulose laquer thinners and you pay for the brand, Did this on the W12 works great +++
make sure you go for a spirited drive for a minimun of 20 miles or more if you can then when you come back and have used the quater of a tank down reserve then just fill it up as normal and happy driving +++ you may have to plug in to get the engine light turned off but it should cure it and wont come back again

I totally second the "paint thinner" idea.

I use Toulene.

It's a great, pure hydrocarbon, was used by F1 as fuel in the 80's when small V8's with big turbo's were making 750hp or more.

It's 114 octane, leaves zero residue, and strips off varnish and gums left over by petrol/gasoline you get at the pump. (Often not very clean stuff it turns out, and depending on the station, can have water, dirt, waxes and all sorts of stuff in there you do not want in your fuel tank, or engine.)

And all that stuff ends up being processed by the cats. Some of it gets trapped there, but the toulene leaves no deposits, and helps to burn off anything on the cats, cleans off excess carbon on your sensors, and in the process also cleans the entire fuel system of varnish and waxes too.

Hit up a paint store and they should be able to sell you a pretty good sized container for about what the automotive shops want for just a few ML/OZ of the same stuff in a fancy bottle.

You will want a long, thin funnel to use while putting this into your fuel tank. DO NOT leave this stuff on your paint if you spill it. It will strip even cured automotive paint if allowed to sit on the paint. It will strip un-cured paint upon contact. (So if someone were to "tag" your car with a spray can, you could take a rag with some toulene on it, and wipe the paint right off.)

It will take household type paints right off too. It's hard on furnature, so don't set the container down on anyting with a varnish that you want to keep. :) (If some toulene dripped down the container outside, and you set it down on the kitchen table for example.. Your wife will not be pleased!) LOL

One more thing. It melts many sorts of plastic when it's undiluted. Obviously not the container plastic, but I've ruined pumps with Toulene, so if you pump it out of the container, you will want to "flush" the pump with oil to keep the pump seals/rubber flaps/pistons and stuff made from plastics intact.

I've learned the hard way that pumping toulene with the common plastic transfer pumps and not cleaning them is a one time only use deal. It will just melt the pump internals over time if left in the pump. (This got expensive when I used to run Toulene as race gas, and bought a fancy pump that screws into a 55 gallon drum. I used it once, was very happy, came back to use it again, and it was melted to the point where it was never going to work again. The vendor claimed it was rated for all chemicals, including toulene, but they would not give me my money back on a 60.00 pump either.)

My 8 breezed through the MOT today, here are the emissions figures.


Fast Idle Test:
CO - Limit 0.20% , Reading 0.04%
HC - Limit 200ppm, Reading 13ppm
Lambda - Limit 0.97 to 1.03, Reading 1.003

Natural Idle Test:
CO - Limit 0.30% , Reading 0.01%

Look pretty good for 175,500 miles.