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Model specific boards => Golf mk3 => Topic started by: Ludwig68 on 18 June 2011, 17:33

Title: Emissions fail
Post by: Ludwig68 on 18 June 2011, 17:33

Hi All

Got an issue with Mrs Ludwig's Mk3. Has failed MOT on emissions. So far garage has changed: plugs & leads, rotor arm & dizzy cap, Lamda switch. Compression test is all good (for a 130k engine) & there's no goo in the header tank. She runs fine but with a missfire between 2-3k revs. We've swapped the ECU from another car temporarily but the fault persists. fuel comsumption is terrible as it's running so rich. Any ideas?

Thanks

Title: Re: Emissions fail
Post by: Khare on 18 June 2011, 17:39

maybe the cat is past it's expiry date?

Title: Re: Emissions fail
Post by: Seanl on 18 June 2011, 21:00

MAF.  :wink:

Title: Re: Emissions fail
Post by: Wayne on 18 June 2011, 21:10

Coolant temp sensor., try a new one.

Title: Re: Emissions fail
Post by: madmanmart on 18 June 2011, 22:05

MAF is a good start...

Title: Re: Emissions fail
Post by: lankylari on 18 June 2011, 22:21

had simailer problem change MAF sensor cat as had collapsed inside the put in lap top to find idle sensor fault, so changed throttle body no plblems now just flow throw mot on emissons just rear axle mounts and welding. all the best.

Title: Re: Emissions fail
Post by: AudiA8Quattro on 18 June 2011, 22:27

I would run VAG com on it.
ECU coolant temp sender is a good place to start....

Title: Re: Emissions fail
Post by: Ludwig68 on 19 June 2011, 11:56

Thanks guys. Looks like MAF sensor change first. Er... where is it & does it matter if it's a 16v engine?

Ta

Title: Re: Emissions fail
Post by: madmanmart on 19 June 2011, 13:30

Quote from: Ludwig68 on 19 June 2011, 11:56

Thanks guys. Looks like MAF sensor change first. Er... where is it & does it matter if it's a 16v engine?

Ta

Yes it does matter, the 16v does not have a MAF sensor.

Is the car a 8v or 16v?

Title: Re: Emissions fail
Post by: simc66 on 19 June 2011, 16:11

Misfire between 2-3k (and crap fuel consumption) on my 16v was a perished fuel pressure regulator hose.

Title: Re: Emissions fail
Post by: Ludwig68 on 19 June 2011, 17:44

Ta everybody. It's a 16v engine. I've had a poke around today & can't see any perished hoses, I've removed all the connections from as many sensors as I can find (hundreds!) & cleaned the contacts with spray cleaner. Still no good. The garage couldn't find any fault codes present when they had it in so I'm still at a bit of a loss. Bugger!

Title: Re: Emissions fail
Post by: Len on 20 June 2011, 09:05

The misfire may not be anything to do with the emmissions!
Try and ECU relay as that does not show up on fault codes.
The emmissions will either be the lambda sensor or the CAT itself.

Title: Re: Emissions fail
Post by: javalin on 20 June 2011, 15:52

temp sensor, air leak, MAF or possibly fuel-pressure-regulator...

James