Emissions stopping me pass mot

londonTiger

first what are your actual readings?

CO = bad cat
HC = unburnt fuel meaning ignition problems
lambda should be close to 1 as possible, lambda is the air fuel mix ratio. Having said that I'm not sure if the air fuel mix ratio taken from the tailpipe means anything if the CO/HC readings are off.

bigjl

Any emissions problems the first option should be use a bottle of CataClean and give the car a decent run.

Many tests have been done to show how effective it is at sorting out emissions problems, I wonder if a lot of these issues are caused by the cars being used for short journeys so rarely get fully up to temperature?

CarMechanics Mag was one magazine that tested CataClean and it reduced the emissions on the vehicle tested enough to pass the MOT.

Clearly it won't work if your car is burning oil.

But it is effective.

And at around £10 it makes sense to give it a try before diving into changing lambda sensors etc.

Edit: Motorguy has already suggested CataClean, so consider this another vote for it.

londonTiger

bigjl wrote: »

And at around £10 it makes sense to give it a try before diving into changing lambda sensors etc.

Edit: Motorguy has already suggested CataClean, so consider this another vote for it.

Cataclean worked for me but where on earth are you buying it for £10. Pretty sure you cant even get it at that trade price.

facade

MarKagei wrote: »

I have changed my spark plugs and changes the cat. My air filter is in good condition


Oh and a computer said my lamber is working fine

You would think a replacement catalyst would make a difference if it wasn't simply running rich.

If the pre-cat oxygen sensor is out of calibration it will run rich* (the fuel trims will be out too, but you need to know what to look for) and it won't flag any fault until the fuel trim runs out and it can't get the "correct" reading from the sensor.

A new generic one is under £20 for most vehicles, less than the cataclean.

*and there simply isn't enough oxygen in the exhaust to completely oxidise the CO, even with a 3 way catalyst to convert NOx to nitrogen & oxygen.

londonTiger

sparkplugs misfiring can destroy the cat, unburnt fuel that makes its way into the cat can ignire there and damage it.

stator

Give VW a call. Ask if you can use their software.

facade

londonTiger wrote: »

sparkplugs misfiring can destroy the cat, unburnt fuel that makes its way into the cat can ignire there and damage it.

It causes overheating of the catalyst which long term will destroy it as you say.

Most cars will turn on the MIL if they detect a misfire severe enough to do this, and store a P030X code, where X is the number of the misfiring cylinder.

mcjordi

mine was a similar reading on my megane last year.. i was sceptical about cataclean..but worth a punt as its on £12 from my factors..
anyway a spirited drive some premium fuel and a bottle of cataclean brought my emissions down massively to a pass even with a knackered cat and lambda sensor..

bigjl

londonTiger wrote: »

Cataclean worked for me but where on earth are you buying it for £10. Pretty sure you cant even get it at that trade price.

I said "around" £10.

I haven't bought it for years and it was £10 then.

As you are the fountain of all prices what is the "trade price" of CataClean?

But you can get it for £12 ish at GSF and £22 for two on eBay with free delivery.

mcjordi

if any of you catacelan users have facebook.. leave them a review as they tend to send you a couple of bottles for free