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Model specific boards => Golf mk3 => Topic started by: devolute on 07 October 2009, 17:46

Title: 1.8 SE MOT emissions failure
Post by: devolute on 07 October 2009, 17:46
I'm failing on emissions.

On a fast idle test I get 0.611% (max 0.300) and a lambda of 1.034 (max 1.030)

This was a re-test. After failing with similar numbers the first time, I was given some liquid to put through the engine. I did this, ran the car round a bit, then bought some of this:
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_274571_langId_-1_categoryId_165750
..with another tank of fuel.  No joy.

The guy at the garage didn't have any suggestions so I turn to you, forum. I have absolutely no idea what the next course of action is.

My Golf has only (!) 85k on it, so I don't want to retire it just yet. The car is in good nick, otherwise.
Title: Re: 1.8 SE MOT emissions failure
Post by: Mikester on 07 October 2009, 17:47
Are you running any mods on it?
Title: Re: 1.8 SE MOT emissions failure
Post by: devolute on 07 October 2009, 17:53
Nope. Aside from some rather tacky wheels that the previous owner put on it, it's completely standard to the best of my knowledge.
Title: Re: 1.8 SE MOT emissions failure
Post by: Mikester on 07 October 2009, 18:10
Well i would think that its either the cat that is broken, or that its overfueling, which has ruined the cat.

Could be over fueling due to a broken/mis reading sensor.

But im not sure how those engines work tbh.
Title: Re: 1.8 SE MOT emissions failure
Post by: devolute on 07 October 2009, 20:37
Thanks anyway Mikester.

I may take it to my local 'VW specialist' before I break down and take it to my local VW dealership.
Title: Re: 1.8 SE MOT emissions failure
Post by: Wayne on 07 October 2009, 20:39
Well i would think that its either the cat that is broken, or that its overfueling, which has ruined the cat.

Could be over fueling due to a broken/mis reading sensor.

But im not sure how those engines work tbh.

+1 sounds like a cat or mixture problem
Title: Re: 1.8 SE MOT emissions failure
Post by: AudiA8Quattro on 07 October 2009, 21:26
Try changing the lambda probe before the cat.
Title: Re: 1.8 SE MOT emissions failure
Post by: Mikester on 07 October 2009, 23:14
Try changing the lambda probe before the cat.

And check the wiring i reckon.
Title: Re: 1.8 SE MOT emissions failure
Post by: Khare on 07 October 2009, 23:17
I'd find someone with vagcom and do a scan, might not be the lambda probe at all. Lambda probes ain't cheap so I'd start off with the cheapest stuff first, like a throttle body clean, and air filter renewal.
Title: Re: 1.8 SE MOT emissions failure
Post by: Mikester on 07 October 2009, 23:23
Needs a difinitve answer, as mot retests are expensive. Thats the problem.

And does a non gti have fault scanning compatability?
Title: Re: 1.8 SE MOT emissions failure
Post by: Khare on 07 October 2009, 23:25
Thing is it could be the lambda probe, but then again it might not be. So if you replace it then that's the most expensive fix wasted. I could be as cheap and simple as air filter renewal or throttle body clean.
Title: Re: 1.8 SE MOT emissions failure
Post by: devolute on 08 October 2009, 10:54
It recently had a full service, so all the air filters should have been replaced.
Title: Re: 1.8 SE MOT emissions failure
Post by: Wayne on 08 October 2009, 11:05
It recently had a full service, so all the air filters should have been replaced.

I would still check.
Title: Re: 1.8 SE MOT emissions failure
Post by: boneybradley on 08 October 2009, 20:16
try the lamda as the reading looks too high (a new bosch universal one is under £50) and also get a temp sensor (£6 well spent)..

oh and all mk3's are vag-com ready (obd1 if pre 95 and obd2 with "full reading" from mid 95... all e.u sold cars had obd2 from 1995 when euro2 emissions came in to force  :wink:)
Title: Re: 1.8 SE MOT emissions failure
Post by: gtigolfthree on 08 October 2009, 20:30
Or mabye the engine is fcucked how many miles has it done and does it use (burn) oil?
Title: Re: 1.8 SE MOT emissions failure
Post by: devolute on 08 October 2009, 22:27
It's done about 85k miles. The engine doesn't seem to go through a noticeable amount of oil and for what it's worth, it sounds 'normal' (My pal had a 1.8 Driver - same engine, same sound).
Title: Re: 1.8 SE MOT emissions failure
Post by: AudiA8Quattro on 09 October 2009, 00:22
Replacing the probe is the cheaper fix, otherwise it will be a new cat.
Title: Re: 1.8 SE MOT emissions failure
Post by: Guy on 09 October 2009, 07:57
At the risk of sounding immensely stupid here.. I once had a calibra (cue flaming) and that failed on emmissions. Turned out to be the O2 sensor..
a) is that the sensor everyone is on about
b) does a mk3 even have one of these, I would guess it does in some guise
3) If it does then is it worth considering as it was a very quick and cheap fix
Title: Re: 1.8 SE MOT emissions failure
Post by: boneybradley on 09 October 2009, 20:15
At the risk of sounding immensely stupid here.. I once had a calibra (cue flaming) and that failed on emmissions. Turned out to be the O2 sensor..
a) is that the sensor everyone is on about
b) does a mk3 even have one of these, I would guess it does in some guise
3) If it does then is it worth considering as it was a very quick and cheap fix

yep same sensor....and it's bolted to the front pipe before the cat