Board logo

Tin top (Tigra woes AGAIN) emissions failure
Mansfield - 13/10/07 at 02:32 PM

I realise you are probably watching England stuff Estonia but it is Tigra time again.

It failed the MOT today - on emissions.

The MOT testers think it is probably the CAT, but they can't be sure.

Description
Description

CO, HC & Lambda are all high. Car runs OK, EGR blanked off - has been for years, new air filter probably wouldn't hurt though.

The cat is just over a year old as is the rest of the exhaust, but it was quite cheap.

Any ideas?

Thanks

David

[Edited on 13/10/07 by Mansfield]

froggy - 13/10/07 at 02:45 PM

why was the speed and temp measurement by passed? if its got a cheap cat on they need a proper thrashing to get through, were you with the car when it was tested?

rusty nuts - 13/10/07 at 03:02 PM

If car had been idling whilst being tested then had a quick run up that is the result I would expect. I always run up to above 3.000 rpm and watch the screen until reading will pass before lowering revs into test limits. As already suggested oil temperature has been bi passed,not always a problem if test has been carried out fairly.

Mansfield - 13/10/07 at 03:12 PM

I was with the car, he held the revs around 3000 for quite a while. Fan was cutting in and out as he kept trying to pass it, so it was hot.

They are pretty good where I go (Alans Test Centre - Mansfield), they did try to pass it.

Edit - I was watching the screen and although it got a bit better over time it was never going to get down far enough.

[Edited on 13/10/07 by Mansfield]

froggy - 13/10/07 at 03:49 PM

i have had a few vauxhalls which have had cheap(half sized cats) fitted that refuse to go through the emmisions,what i do is send the revs up to 4.5k and watch to see how far the hc go down, if they drop below 100ppm then the co will start to come down but it looks like cat to me too

rusty nuts - 13/10/07 at 03:50 PM

Lambda sensor may be at fault? cheaper than a cat and can be tested. Coolant temperature sensor could be at fault? If you can get at it, easy to test

wilkingj - 13/10/07 at 03:53 PM

quote:
Originally posted by Mansfield
I was with the car, he held the revs around 3000 for quite a while. Fan was cutting in and out as he kept trying to pass it, so it was hot.


no No NO!!!..
Service it first... plugs, oil, filter, Air filter etc.

Then just before the MoT take it for a 20 minute THRASH. Give it the works, and then arrive at the MoT centre with it RED HOT. Then do the test.

Mine failed exactly like yours.
You need the service, especially the oil and filters. I didnt believe how much difference it made.

Just going in with the engine warm isnt enough, especially with higer mileage cars.

I think you will notice a big difference in the readings.

My MoT Man is under orders to take my car for a good thrashing before the emissions test. Its worth the effort.

Mind you if the CAT is dead, then that will not help, and you would have needed to do some more work anyway.

Mansfield - 13/10/07 at 04:08 PM

New cat is £70, assuming I need one is that too cheap?

Got to go and fix the in-laws Corsa now, does it never end?

Thanks

David