Hi,

I am hoping somebody can help me out.

My 1996 1.8 Mondeo passed its mot , but I noticed that the emissions have risen dramatically over the last 4 years.

2007 HC 36ppm
2008 HC 47ppm
2009 HC 134ppm
2010 HC 170ppm

Car runs fine, and has had new plugs leads, all filters.

BTW CO emissions barely changed over the 4 years

Thanks for any advice anyone can offer

 

Could just be engine wear over the years dependent on millage etc, or it may benefit from a new Lambda sensor, as this may have gone out of scope over the years.

Martin

 

Do you pussy foot it around all the time ?, try banging it off the limiter once in a while to get cat nice and hot, will cause zero harm if maintained correctly, pattern cats are famous for needing a serious thrashing prior to the mot.
tabetha

 

Does the car burn much oil? How many miles has it done?

 

Thankyou for all replies so far

Ok Car has covered 130000 miles

Cat is original as is lambda is, I was under the impression that if either cat or lambda were bad then the CO would also rise ?.

I use about a half ltr of oil every 2000 miles.

Thankyou everyone for your help, this is now just bugging me although the car has a full mot now, I am already thinking of next year :-(

 

It may well be oil burning that is causing an excessive hydrocarbon reading, or also unburnt fuel is coming from the exhaust. Are you getting any misfires at all? Could be worth a change of the lambda sensor as they sit in the flow of exhaust gases so do clog up and give incorrect readings over time.

 

Thankyou

YES there is a misfire but only noticable at idle.

I have also plugged the EGR pipe, as it used to missfire constantly when it was connected ?

 

Sounds like this could be the issue then, I guess blocking the EGR pipe is only masking a fault that is still there. I would probably get whatever is wrong fixed first, get another emissions test done then go from there!

If you do have unburnt fuel passing through the exhaust, it will knacker the cat in no time too. Check the t-piece in the vaccuum lines, its under the coil pack if I remember right, these often split causing all sorts of running issues.

 

thanx

EGR was blocked 3 years ago so possibly not the culprit ?.

And yes you do remember right the t piece is under the coil pack and has been replaced :-(

As i say got a years mot but am worrying about the next one already.

 

I have no idea then really, I would put the EGR back to how it should be and find the real cause of the misfire, as it sounds to me that by blocking off the egr it's just covering up another fault!

By removing the EGR, the combustion temperature will be higher, so it might just need a hotter spark plug if you want to keep the EGR disconnected!

 

Ok Rich.

Will put it all back and try to find the issue,, can you confirm if i am right or wrong though ?, that if the cat or lambda were to blame then the co reading would also rise ?.. seriously doing my head in, not got the money for diagnostics, all repairs always done by myself but emissions are a real pita :-(

 

The CO might rise if the lambda isn't reading properly, although it might not, i'm really not sure. An air leak may be a cause too, get some easy start spray and squirt it round the inlet manifold area / vaccuum lines. If the rpm fluctuates, then you've found your leak!