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        General >> Problems >> mot faliure emissions 
        
(Message started by: python9 on Feb 25^th, 2009, 1:56pm)

Title: mot faliure emissions
Post by python9 on Feb 25^th, 2009, 1:56pm

my 24v scorp failed its mot on emissions

fast idle test
speed 2750 3150 /min
co 0.3 %vol actual 0.49 fail
hc 200 ppm actual 25 pass
lambda 0.95 1.09 actual 1.05 pass

2nd fast idle test
2750 3150 /min
co 0.3 actual 0.50 fail
hc 200 ppm actual 24 ppm pass
lambda 0.95 1.09 actual 1.04 pass

natural idle test pass
speed 625 825 /min
co 0.5 %vol actual 0.5

has anyone any idea what the problem could be is it lambda sensor or a cat problem

Title: Re: mot faliure emissions
Post by martin_rowe on Feb 25^th, 2009, 4:27pm

Looks like cat problem, mixture is good (llambda reading)

Title: Re: mot faliure emissions
Post by python9 on Feb 25^th, 2009, 5:09pm

how do i know which cat is at fault

Title: Re: mot faliure emissions
Post by amigafan2003 on Feb 26^th, 2009, 8:04am

Get an OBDII reader on it - the post cat O2 sensors are there purely to check that the cats are ok - if either cat is bust, it'll throw and OBD error.

Title: Re: mot faliure emissions
Post by martin_rowe on Feb 26^th, 2009, 8:40am

Post cat sensors will show little variation in output voltage, if one is fluctuating that will be the side with the 'duff' cat.

Title: Re: mot faliure emissions
Post by python9 on Feb 26^th, 2009, 10:47am

how many pins are are on the obd 2 socket on the 24v scorpio 1997

Title: Re: mot faliure emissions
Post by scorpio_man on Feb 26^th, 2009, 10:50am

16

if you don't have access to an obd-2 reader, just use a multi meter on the rear lambda's.

as posted earlier, if your reading is jumping about (0.2-0.8volts), then that cat is faulty.

hth

Title: Re: mot faliure emissions
Post by tlundkvi on Feb 26^th, 2009, 11:44am

on 02/25/09 at 16:27:17, martin_rowe wrote:

Looks like cat problem, mixture is good (llambda reading)

Then on the other hand, the HC value is very good. Python, have you tried the motorway in 2nd gear? Cleaned the MAF? When mine failed MOT, I had 2 bad cats, but in addition there was a very dirty MAF, a vacuum leak and a failed injection temp sensor. Fixing those made the car produce a better lambda value, but emissions didn't change much. If I remember it right, the lambda value is independent of the working cats or not, so AFAIK bad front lambda sensors are not ruled out.

Title: Re: mot faliure emissions
Post by Highlander on Feb 26^th, 2009, 1:52pm

John is the 24v still road legal?

If you bring it with you next weekend i'll scan it for you.

Title: Re: mot faliure emissions
Post by python9 on Mar 1^st, 2009, 9:09pm

yes she is still road legal the mot does'nt run out till march 14th cheers stuart

Title: Re: mot faliure emissions
Post by martin_rowe on Mar 2^nd, 2009, 8:49am

thought it had just failed ?. fail cancelles out previous pass.

Title: Re: mot faliure emissions
Post by python9 on Mar 2^nd, 2009, 12:50pm

not if it had more than 2weeks on it

Title: Re: mot faliure emissions
Post by martin_rowe on Mar 2^nd, 2009, 1:19pm

sorry incorrect

Title: Re: mot faliure emissions
Post by amigafan2003 on Mar 3^rd, 2009, 8:58am

As not having a valid MOT is a document offence and not point endorsdable, an MOT failure does not invalidate a current MOT certificate that has yet to expire. So, to summarise, you couldn't be prosecuted for not having a current MOT (because you do!)

However, all failure items on an MOT do affect a cars road worthiness, so you could be prosecuted for driving an un-road worthy vehicle (remember, having an MOT is no guarantee the vehicle is road worthy).

Title: Re: mot faliure emissions
Post by Scorpio_Mike on Mar 3^rd, 2009, 10:31pm

Long time ago - before computerised MOT's, a mate of mine always used to drive 'old bangers' and put them in for an MOT every 6 months - on the grounds that if it failed and it was going to be expensive to fix, he could then sell the car on still with 6 months MOT !

Pretty sure a fail these days goes on the DVLA database to stop this kind of thing.

Title: Re: mot faliure emissions
Post by Highlander on Mar 3^rd, 2009, 11:06pm

Interesting one this, I've done a little researching on it and this is a summary of what i found.

If your car fails an MOT while the old MOT is still valid.

If you repair the fault that failed it but dont get it retested

eg: it failed on a bald tyre and you replace the tyre at home.

Then you can still drive it on your old valid certificate until that expires.

BUT if you still drive it without fixing the fault that caused it to fail the MOT then you are knowingly driving a defective vehicle, you will have a valid MOT but you would be charged by the police as they can prove you knew it was defective. (it shows up on their ANPR as an MOT fail)!!

Also, your insurance company will gleefully invalidate your insurance in the event of an accident/claim for the same reason.

So... although you would probably need to meet one of our boys in blue on a really, really bad day to get yourself charged for high emissions the fact of the matter is if you have a bump you're not insured.. :o

Title: Re: mot faliure emissions
Post by Highlander on Mar 9^th, 2009, 10:04pm

OS cat gone to heaven,
NS cat on life support but hanging on :)

Two new cats heading to Aberdeen soon i think :)

Title: Re: mot faliure emissions
Post by python9 on Mar 10^th, 2009, 8:45pm

yep 2 on order now should arrive by thursday

Title: Re: mot faliure emissions
Post by Highlander on Mar 10^th, 2009, 10:03pm

Which ones did you get and where did you get them John?

Title: Re: mot faliure emissions
Post by python9 on Mar 11^th, 2009, 6:56pm

i got the 2 ceramic cats for £158.75 delivered http://www.buypartsby.co.uk

Title: Re: mot faliure emissions
Post by Highlander on Mar 11^th, 2009, 7:00pm

Good site that, cheap for most things too, i use it quite a bit