Today I mostly .....

[GvidoR]

From sugar, eh?

You put a load into it, turn it on and when you come back the floor is all wet and there is no washing machine in sight?

[GvidoR]

Enjoying the Windows 8 sports app, unfortunately Buffalo Sabres ain't doin' so well this season.

[excossack]

Got my stages passes through for the WRC

[Tom.]

Best make sure that new washing machine works ok with 220v

[excossack]

You buying from Southern Ireland?

[excossack]

Excellent...its that a bloke on a wheel with a dynamo attached?

[GvidoR]

Are there any ways to reduce exhaust emissions? I can't get the Bora through MOT. First time it just failed on high idle, but a while later, I put a bottle of that stuff which is supposed help emissions, driveability and whatnot, drove the car at 5-6k RPM's a few minutes before the test and it failed on the low idle as well as high idle. Could it be getting worse? These things were supposed to help. Fresh oil and filters are in it too. Is there anything else that can be done or I should just get rid of it and buy a 1.9 TDI Vento?

[excossack]

When you took the car is was it nice and hot? I would go for a good blast on the motorway for more than a few mins to get the stuff worked through and maybe top with fresh fuel.

Are all the sensors working OK? I.e Lamda, Coolant temp sensor etc?
Is it failing by much?

[GvidoR]

Yeah, it was hot allright, not over 90°c though.

It's supposed to be 0.30% or less and it was 0.97%, so I don't know...

[GvidoR]

Injection

[GvidoR]

No, there are no warning lights on. It's not chipped either.

The car runs perfectly apart from the excessive amount of smoke coming out of the exhaust.

[eveshamsteve]

Check and clean engine breathers. Especially if oil has not been regularly changed or if car does short journeys.

[Zelandeth]

That's running well rich...Saab managed better CO reading than that (0.32% and 7ppm HC) and it doesn't even have a cat...or ECU for that matter. What were the HC and lambda readings for the Bora?

Obviously make sure the car's in a good state before the MOT - so breathers and everything are clear, new air filter, that it's got nice fresh oil (of the correct type!) in, and has had a decent run so the cat is properly up to temperature (which is more important for the emission test really than the exact engine temp). This is one of the reasons that I tend to give a car a full service before an MOT...so if something comes up like this I've already got half the possible problem boxes ticked off - and it tends to be a good time to spot faults that might otherwise cause problems at the test.

If all of these are ticked off, most likely reasons I can think of off the top of my head for a high CO reading would be either a knackered cat, or more likely a knackered lambda sensor. This can lead to a situation where the car effectively thinks that it's running leaner than it is.

Coolant temperature sensor fault would also give a high CO reading - but in a car of this age I would probably have expected it to flag a check engine light.

I would be very interested to see what lambda value it thinks it's seeing compared to the actual result.

Before we over-complicate things though - the exhaust isn't blowing anywhere is it? Sounds silly, but I've seen even relatively tiny holes cause the emission control systems of cars of that sort of age to throw a serious hissy fit and get utterly confused.

This is assuming that you're seeing black smoke due to a rich fuel/air mixture. If it's blue smoke, that's a different story, and is due to the engine burning oil. Given the complexity of the breather systems on modern cars, there are quite a few ways that this can happen - but being honest, the usual favourite is a mechanical fault - Worn piston rings/bores, worn valve stem oil seals, or a failed head gasket being the three most likely that I can think of. Assuming the breather system is in all in order and the engine has the right oil in (if someone's stuck 0W oil in an engine designed for 10W or 15W oil that could probably have a similar effect), best thing to do would probably be to get a dry and wet compression test done and compare the figures to the manual. Low compression results - especially if the wet test is a lot higher - would tend to suggest a worn engine. What sort of mileage has it covered? Generally smoke from worn valve stem oil seals usually appears when you come off the throttle from higher revs and on the overrun (due to the increase in manifold vacuum pulling it through), wheras smoke from worn piston rings or bores tends to appear when the engine is actually under load.

PS: If it was me, I wouldn't waste money on additives like that - they're 99.8% snake oil. If a car's failing an emission test, there's a reason. Sticking some goop into either the fuel or the oil isn't going to fix it, and looking at the ingredients list on some of them - I think are more likely to do more harm than good. Much better to find the problem and actually fix it - you'll have to sooner or later anyway. The only stuff out a bottle that goes in the tank of any of my cars is the lead replacement additive for the Skoda. That comes out of a suspiciously non-shiny bottle which is strangely lacking in claims for miracle cures for all mechanical ills.

[GvidoR]

^ Running at 3000-4000 RPM's in the video.

[Zelandeth]

Can't see the video unfortunately as it's set to private.

So both the HC and CO values are too high (just looked at the last MOT for the 306 here, and the HC limit is 200ppm - unless it's different in Ireland?).

It looks from the thumbnail at least as though that's grey/black smoke which points to too much fuel. So checking things like coolant temperature sensor (should be easy enough to check with a multimeter to see if the values are sensible) would probably be my first port of call. Lambda sensor would probably be number two on the list - though that's tricker to check by anything other than substitution I think.

If it's been running that rich for a while possible that the cat will have had it...