Emissions failure

[Brian Voce]

I have a 480 Celebration 2 litre. The car is filing it's MOT on the fast idle emissions test. It isn't burning oil (spark plugs are a text book colour) and the fuel consumption is good. The Main Dealers have changed the CAT the CO2 Potentiometer, and sent the ECU for repair, (came back as 'no fault found') I think they are just guessing at the problem as they seem to have no more of a clue as to the problem than me.

Does anyone have an idea as to what might be causing this? (an injector clogged perhaps?)

Cheers Brian Voce

[aibast]

leaking exhaust? What did they measure?

[martinholmesuk]

Bad engine temp sensor so running rich when hot.

Dirty or fault air temp sensor

faulty throttle switch

[felyx]

i had the same problem with a 2 litre and changed everything ie throttle postition switch lambda sensor cat temp sensor etc etc,
what eventually helped was changing the oil with a flush additive , taking the air filter and turning up a t 1055am for a while you wait M.O.T at 11am after driving hard ( very ) for 30 miles before hand to really heat everything up , i also held the throttle bouncing off the rev limiter for 15 seconds before emmisions test etc.

cheers felyx

[Brian Voce]

Thanks to those who answered my original post. The main dealers have now given up on the car leaving me with a bill for £600. They calim to have tested all the sensors replaced the MAF and co2 potentiometer, changed the CAT tested the ECU and the injectors for leaks. Still no improvement, the car is still overfuelling. Now they say the only thing left is to take the Cylinder head off! Why?

Any suggestions for a way forward would be appreciated.

Cheers.

[rpruen]

Is the car used for short trips mosty?

If so then oil contamination is a possible problem. Taking the car for a good hard run, using full throttle may help.

Also try STP fuel system cleaner, add the whole bottle to 1/4 tank of fuel, and drive the car hard. Then change the oil, and see if the stealer will test the emissions (hope they will as they failed to fix the car).

Also try a different garage for the MOT, maybe the test gear is faulty in the one you have been using?

Sounds like Volvo have done just about everything. Did they change the oxygen sensor? You don't say, and that could be the problem.

Hope some of that helps

Richard