MOT dilemma

[clk208]

Hi knowledgeable folks,

The MOT lapsed on my W208 on 29th Dec as I was spending Christmas/New Year abroad this year for the first time and totally forgot about it, stupid of me.

I went along to a council run testing centre earlier this week - basically they can only do the tests and do not carry out repair work so no incentive for them to fail and carry out unnecessary work.

The car was fine until it got to the emissions test. They tried it 3 times and the CO was coming down slightly each time but was still slightly over after the third go. Final readings below:
FAIL - CO - 0.36% (limit is 0.30)
PASS - HC - 63 (limit 200
PASS - Lambda - 1.011 (limit 1.030)

Oil/filter and air filter were changed in Nov 2011. Genuine Bosch MAF fitted about a year ago along with Bosch left bank O2 sensor.

With the readings above do you think there is any chance of a fuel cleaner type product bringing it into spec or am I wasting my time and should I get it to a STAR?

Now obviously with the MOT being up I am breaking the law driving it to a garage to be repaired or whatever so want to minimise the amount of driving I do. The fuel cleaner thing would mean less miles assuming it worked otherwise I would have another wasted trip back to MOT centre (c 15 mile round trip).

Any thoughts folks?!

 

[davidjpowell]

When my cars have failled on emmisions it has always been when it's been stood.

Garages usual cure is an Italian Tuneup. Not sure how you can do this legally with no MOT though. Perhaps a spirited drive to the MOT!

 

[SilverSaloon]

injector cleaner and give it a good italian tune up.... obviously close to the garage. book it in for a retest, and then drive it around the block. you'll be covered as you are on your way to a pre-booked test.

 

[martyz]

when was the last time the plugs were changed? can make a big difference.

 

[clk208]

Great plan - I think that's what I will do then. Perhaps I will add some fresh fuel en route too as the fuel in the tank may be 5-6 weeks old due to me not driving much and having been away.

Just had another thought. In my ownership of the car (since Dec 2006) the spark plugs have not been changed - silly of me really but my annual mileage is very low. Could a fresh set of plugs result in a cleaner burn/less CO? 12 plugs and not cheap so I don't want to get this done if it is going to have no impact (particularly as I will probably have to get a garage to do it which will mean driving there).

Edit>> Just seen Martyz's post above. Maybe this calls for a plug change after all.

 

[Scott_F]

An additive put into a tank that is low-ish on fuel should do the trick. You can let the car reach normal temperature on your driveway and then rev it as you would on a normal journey (or harder !) for 20 minutes or so.

 

[Doodle]

As mentioned, the Italian tune up does wonders. Did this for a mate's Corsa 1.0 last year, came so close to getting it through with a failed CAT.

Arrived at the test centre bang on start time with the car hot, and I mean stinkingly hot. Dropped the CO from .679 to .305...so near and yet so far!

 

[W4SIM]

A car that has been stood for a while needs a very good italian tune up, perhaps with some fuel additive for good measure, but the driving is what really does the trick. The engine temprature when its on the Co2 machine also makes a massive difference, its more likely to pass on a hot engine.

Also, if the test is pre-booked then your not illegal to drive it there. And im sure if you miss that second exit on the roundabout then you have to go another 5 miles of heavy driving before you can turn around, if your roundabouts are anything like mine!!!

 

[markjay]

Injector cleaner (Redex or Forte) followed by Italian Tune-Up is a good idea.

And then there's this:

CataClean Global Ltd.

Car Mechanics Magazine tested it and said it did reduce emissions.

Filling up on empty tank with some Shell V-Power and driving energetically might also help.

HTH.

 

[clk208]

Thanks guys. Going to try the additive and Italian tune up and put it in for the retest. If it fails I will get a new set of plugs. Will post back how I get on.

All this time off work pretty inconvenient. Will be back to using a proper garage next year for the MOT. I guess the council test option only good for something that is pretty much guaranteed to pass first time.

 

[clk208]

Just an update on my little emissions issue - positive news.

Got a bottle of Cataclean (my local shop didn't sell Forte/Redex) and went for a couple of long hard drives. Even though I "only" have the 320 V6 it is pretty difficult to find appropriate roads/hills to work the engine hard for more than a few seconds without being into serious speeds or worrying about leaving the road (non-branded tyres don't help here I guess - on my list to change!).

Just been for the retest and it just passed (on the second go and after the testers having to rev the engine for quite a while) so good news I suppose but obviously everything is not in 100% tip top condition.

Not going to be doing a huge amount of driving over the next few months but will book in to 124works I think for a STAR/once over when the weather improves.

 

[zenman63]

Can you not dive it in 2ed and 3ed to get the revs up?

 

[clk208]

Can you not dive it in 2ed and 3ed to get the revs up?

Yeah I did stretch the revs up in 2nd and 3rd for a while. Although it would be revving pretty fast at say 55mph in 2nd the load on the engine would be pretty minimal - say 5% of throttle to maintain the speed. Any more throttle is enough for the speed to keep increasing rapidly and progressing to running out of revs!

I'm not sure whether an Italian stylie tune up requires high revs or high load on the engine but I'm guessing a bit of both - the latter is harder to achieve on public roads!

No wonder the big Merc engines can cover so many miles - guessing most are only used to about 20% of their full output for regular driving around and motorway trips at or around the UK speed limits.

 

[Dieselman]

No wonder the big Merc engines can cover so many miles - guessing most are only used to about 20% of their full output for regular driving around and motorway trips at or around the UK speed limits.

Sounds about right, you only need ~20Hp to travel at 70mph.