pug 205 1.6 gti (F reg) + smoky exhaust

I am experiencing a smoky exhaust. The smoke isn't blue or black just greyish.

Any idea what causes the smoky exhaust and how I can rectify the problem. The car runs and idles well.

Thanks

Reply to
species8350
Loading thread data ...

Have you checked the water level? Steam-coloured exhaust can signify a head gasket on the way out.

Ron Robinson

Reply to
R.N. Robinson

Water level is 'A OK'

Exhaust smells a bit oily

Sp.

Reply to
species8350

If smoke is all the time, or under acceleration, it's an indication of worn piston rings.

If on start up, or backing off the throttle, it's likely to be valve seals.

-- R

Reply to
R

I don't think that either really apply

Its not really noticable when driving. But when at the lights, or in a traffic jam, or just idling, then its notceable

Thanks

Sp.

Reply to
species8350

Black smoke is burning too much fuel, the 205 does have some hesitaton problems at idle, A lot of people chip them to sort this issue. It could well be overfuelling, I suspect a quik emmisions test would tell you that though, as emmisions would be up a fair bit.

It doesn't sound like any oil is being burned as this would usually create a blue haze from the exhaust.

It could be steam vapour, especially if you have an aftermaket boy racer exhaust fitted as these can hold a lot of water inside them, especially if you never do high mileage too warm them up and you wash it regularly or use car washes.

Don't dimiss impending head gasket failure though, it would only take a very very small leak into the cylinders to create a steam trail, it would not even have to leak enough water to effect the water level.

Andy

Reply to
dreadly

Thanks for responding

What about the problem only occuring at idle

What did you mean by 'chip them'

Thanks

sp.

Reply to
species8350

The GTI's - I don't know if it's only the 1.9 or both engines suffer from hesitation at low revs and idle badly. The fix for this is to have them chipped, i.e. have the ECU reprogrammed.

If a car is only smoking at idle that is usually just because it is more noticable as the exhaust gases are travelling a lot slower.

If a car had blue smoke at idle it would indicate that oil was running down the valve stems past the oil seals and into the combustion chamber. This is usually caused by hardening of the seals and is common on engines that tend to run at higher temperatures such as french petrol engines, however, you state the smoke is not blue. This small oil leak is not enough however to cause blue smoke at higher revs so the usual rule is that if the smoke continues to below out even under load then oil is being pulled past the oil scraper rings on the pistons on the downward stroke, thus burning oil. This can only be corrected by replacing the rings and re-honing or reboring etc... - usually fairly terminal as bearing etc usually need replacing also after this kind of wear.

Excess fuel, which I suspect is your problem can be caused by several faults, one of which is blocked fuel injectors, another is a faulty Lambda sensor, another is a broken/faulty ECU etc....

As I said earlier, the only real way to tell what type of smoke it is would be a gas emmisions test, post the results and lets have a laugh. If the Hydrocarbons are way up it would tend to point to too much fuel/oil. If emmisions are ok, then it's probably water vapour.

I hope I got that correct ??? - And real mechanics out there please feel free to corrct me, I have nothing against learning new tricks ;)

Has yours got a CAT ???

Andy

Reply to
dreadly

No CAT

IS ECU another name for the air flow meter? If not, I don' think I've got an ECU?

Wouldn't too much fuel lead to black smoke?

What about the effect of the breather system on the quality of the exhaust?

Reply to
species8350

Your ECU is inside under the dash board.

Reply to
naughtymutt

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.