MOT fail on emissions, help needed.

Bludge · Post by **Bludge** » Thu May 15, 2014 8:46 pm

what are the chances that its just knackered old plug causing numbers like that? or ia that being a little too hopeful? lol.

judderod · Post by **judderod** » Thu May 15, 2014 9:35 pm

Sounds like you might have found the problem! Especially if one plug was worse than the others. I take it your air filter is in better condition than your plugs?

If you had smoke before, you might want to get the cat really hot to burn off soot deposits etc. Get the car up to temp and let it sit and idle for at least 10 minutes. The rev it up to 2 - 3K RPM for another 3 - 5 minutes keeping the throttle fairly steady, all while the car is still. It's best if you do this shortly before going in for the emissions test. Lastly make sure it has some decent fuel in like shell v power or super from esso or Texaco.

Bludge · Post by **Bludge** » Thu May 15, 2014 9:45 pm

well the air filter looks ok, but its an aem one taken off a breaker. will have to look into cleaning it.
Im wondering if its worth geting some cataclean and running it through and taking it back for a retest. i guess i will ask him how many retests i can go for before he starts charging!

Post by **paul72** » Thu May 15, 2014 9:46 pm

Just remember how much different my car is now i replaced o2 sensor as it runs like a dream now

plus good old super 4's ive been using them for a year an no probs yet

Bludge · Post by **Bludge** » Thu May 15, 2014 9:51 pm

yeah work were ment to call me back earlier with a price on the o2 sensor but never did, gonna call in tomorrow. listed as about 80 quid on the site so should be pretty cheap on my staff account. dont want to change the cat unless i have to so will try all that first, then do the cat as a last ditch effort. and if it still fails i'll be coming up to see you @TheBusOfWoe!

judderod · Post by **judderod** » Thu May 15, 2014 9:57 pm

Bludge wrote:Im wondering if its worth geting some cataclean and running it through and taking it back for a retest.

I started typing that but couldn't remember the name of it! Definitely worth a go.

There's a way to run an emissions test without 'booking on' the vehicle with the reg etc. If your tester knows how to do it, they can check the emissions before actually doing the re-test. But once it's booked on you get one shot. On the emissions computers I've used you have to come right back to the very first menu screen (the one they see first thing in the morning).

Post by **paul72** » Thu May 15, 2014 10:21 pm

Make sure u get the right o2 sensor as u saw wat happened to mine, if u can take urs out an check it first

Post by **Thebusofwoe** » Thu May 15, 2014 10:32 pm

I think that changing ur plugs and possibly the o2 sensor as well, should fix the problem tbh. As also stated, the cat is most probably full of deposit jobby so will need burning off just like the previous post suggests. All sound advise

. By all means, if still no joy, i will get it through

Bludge · Post by **Bludge** » Thu May 15, 2014 10:34 pm

I can always take it back if its the wrong one paul, i got loads of stuff i havent used to take back!

Cheers Chris, i will get the o2 sensor in next week and see how it goes!

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu May 15, 2014 10:38 pm

Bear in mind that 02 sensors can be an absolute bitch to change... Corroded solid into the exhaust and rotten so the nut flats round off. Might be worth trying an emissions test before doing the sensor?