Emmisions

[Sikastag]

Hi everyone,I'm a bewbie and hope I can post this??! I just put my T reg 1.4 16v golf through mot but Emmisions were off the scale....seems to be the hydrocarbon part...went home,filters,oil,redex and cat cleaner....no difference to be  honest,still gets to 3500 rpm on tester and looks good and then chucks out this blue/grey smoke which I think is fuel or maybe oil??? Reading goes off the scale.....any help/ideas please??? It's the only failure so worth looking at fixing....thank you.

[Wazzzer]

cat or lambda?

[itavaltalainen]

HC being high can be fuelling being off or because it burns massive amounts of oil.

If it burns oil a lot you should know I guess? Does it need topping up a lot?
Does it run reasonably normal apart from HC fail?

Fuelling issue can be due to air leaks on intake side, MAF, ignition parts, temperature sensor, etc....

Does it show any fault codes?

[Sikastag]

Thanks for reply...this evening I have taken notice of what you said and the car runs fine except I now thinks it runs a bit fumey...the temperature gauge eventually gets to 90 but as its driven it drops back to half way...it seems it's then you get the smoke..I took the breather off the where the air filter is and it ran ok, where would oil get into the system to make it smoke and would the temp gauge normally drop back like that?? I hav to  clue and only got until Monday for retest so help help help please!!

[itavaltalainen]

Your thermostat is knackered. So it never closes properly and the car overcools.

Without a fault code scan or looking at engine measuring blocks telling why it fails is gonna be tricky, apart from the usual stuff like looking for air leaks, spark plugs and cables (if applicable), coils, ....

Retest on monday? Don't you get 10 working days for a free retest if it fails?

Where in the country are you?

[Sikastag]

Sorry for long wait on reply... I took vehicle to local VW mechanics and they came up with injector number three showing fault,cleared it and it soon came back again!! Don't know what they did but on re-test at 3500rpm it's all fine with Emmisions machine and then it starts chucking out this white smoke that smells like oil being dropped on the exhaust...resembles a red arrow with the smoke.. Hydro carbon section on machine goes of the scale...only got until Friday before old MOT runs out and she becomes a £50 scrapper!!

[itavaltalainen]

Not too much info to go on.

Of course fault will come back if you delete and have not fixed the issue.

What was the exact VW fault code it threw for third cylinder?
If there is a fault on injector next move would be to move the injectors around and see if the fault travels.

PS: Am assuming garage have tested compression. The 1.4 is notorious for piston tilts and faulty rings.