Car has been stood for the last 14 month, has had fresh oil, plugs, air filter, fuel filter, etc, 3000 miles on new Cat, fresh fuel, bottle of cataclean, motorway trip to MOT station. No misfires or rough running. No fault codes stored apart from secondary air pump delete which was done years ago and passed previous MOT's

CO readings were 2.8 should be 0.2

HC was 67ppm

Lambda was 0.99 this was on idle test, so HC and Lambda within range, took it for a 50 mile drove it like you stole it down the motorway, and 2nd Co reading was 2.3, any ideas where to start to look for a cure,

 

Cheers Andy.

find a better mot station ;-)

o2 or map sensor possibly

If you've got no fault codes and the data looks good, I would guess at o2 sensor or the cat. Was the cat a non-genuine one? I've had brand new cheapy cats fail the MOT at work

Clean throttle body.

 

Clean intercooler and pancake pipe.

 

Stick some vpower in and keep her on boost for a while.

As above, and turn AC off, as this will also lower emissions slightly.

engine flush with forte and put can bg44k and kick cars hole in and it will prob be fine works with me everytime in my work

There's a few sensors that can be goosed without throwing a code. Looking in VCDS measuring blocks is the only way to be sure that the engine sensors are all working correctly.

Certainly worth checking the ECU is getting an accurate reading from the coolant temp seansor, CTS failure will cause the ECU to fuel incorrectly, & is one of the most common faults to afflict VAG cars.

If you've got no fault codes and the data looks good, I would guess at o2 sensor or the cat. Was the cat a non-genuine one? I've had brand new cheapy cats fail the MOT at work

 

Miltek 200cel Cat, passed last MOT

 

Clean throttle body.

 

Clean intercooler and pancake pipe.

 

Stick some vpower in and keep her on boost for a while.

 

Will have to check these, usually clean as have catch can fitted which needs regular emptying so must be doing it's job. V Power always, won't let her drink anything else

 

As above, and turn AC off, as this will also lower emissions slightly.

 

AC was off

 

engine flush with forte and put can bg44k and kick cars hole in and it will prob be fine works with me everytime in my work

 

Engine flush was part of the work done, and new filters all round.

There's a few sensors that can be goosed without throwing a code. Looking in VCDS measuring blocks is the only way to be sure that the engine sensors are all working correctly.

Certainly worth checking the ECU is getting an accurate reading from the coolant temp seansor, CTS failure will cause the ECU to fuel incorrectly, & is one of the most common faults to afflict VAG cars.

 

CTS may be worth replacing seems to take longer to warm up, than what I remember, don't have VCDS but a code reader that can read live Data, temp was showing as 90 in traffic and 73 on motorway, is it suppose to drop on motorway or stay at a constant 90?

Is there test you can do on the O2 sensor?

...seems to take longer to warm up, than what I remember, don't have VCDS but a code reader that can read live Data, temp was showing as 90 in traffic and 73 on motorway...

This might be the signs of a bad thermostat.

If your engine temperature is dropping when cruising, I'd suggest checking the thermostat. It should maintain 90ish except when warmed up and in slow traffic when you can go on heat.

Hope it's not the thermostat, fed up of changing it, already had 4 in 6 years aftermarket x2 and OEM x2 :think: and 3 OEM CTS

Once up to 90c it should stay there. Temp dropping at cruising speed could be a stuck stat, air lock, or worst case HG failing.

UPDATE.. Now passed.

Did some logging, O2 sensor was fuggered, and drain plug on catch can not shut properly after last drain, DOH!!

Will have to keep an eye on thermostat, was working as it should today.

Thanks for your help guys.