so, are you saying that it might not actually be a valve seal or ring failure but might be an issue with the cats? how does a prob. with maf or temp.sensor ruin your cats? (just out of curiosity)

 

I am only suggesting those parts as culprits.

Black exhaust means you are running rich - too much gas or not enough air.

MAF (Mass Air Flow Sensor) measures the amount of air coming into the intake. If it is failing and sends a signal that more is coming in than really is you will run rich.

Coolant sensor The ECM uses this reading to determine if it is a cold start or warm start if the engine is cold it will need more fuel to choke it and get it to start. If the sensor sends the wrong info the ECM may think your engine is cold and enrich the fuel mixture. You would see a fluctuating gauge on the instrument cluster, not in the middle.

Maybe it's a throttle body issue, try aligning it with the vag-com.

Maybe your O2 sensors are bad and Not telling the ECM your running way to rich.

Don't you have any DTC's for us? have you scanned the ECM for fault codes with a vag-com?
That would help shine some light. If it says nothing, No codes,I would do a throttle body alignment. Then I would order the cooling sensor and replace it. They seem to go bad real often and test the MAF. The cooling sensor is cheap and goes bad anyway but the Maf is not so cheap.

Read this through;
http://www.vaglinks.com/Docs/Audi/Mi...rse_941002.pdf

It will help give some understanding of the system, In turn will help you diagnose it easier.

 

White/bluish smoke at start up = oil in a cylinder at start up. Prolly leaking valve seals..

White smoke that smell 'sweet' = coolant

Blackish smoke = too rich

So:

Says what?

 

i wish i had some codes to give you guys too.
I just got the vagcom in the mail the other day and haven't set it up yet, but hopefully in a few days ill be able to have it up and running.

In the mean time, just for discussion sake, i was thinking of all the input you guys have given me regarding this and, personally, i am coming to the conclusion that the smoke might be coolant. ( again this is just a personal conclusion based on what im learning but hopefully we'll have a more definitive answer with the codes).

The reason i am saying "coolant" is because..the smoke is WHITE..it does have somewhat of a sweet smell to it and what i'm noticing is that after driving the car at normal speeds, for not even that long, th engine gets real warm..on a cold day. ( in the past, on a cold day, the engine would still be cold after driving for a while).

I think it might be my water pump.
Again all of this is speculative but what im wondering is how directly related is water pump failure to timing belt?

Hypothetically, if i do have a water pump issue can this problem cause my timing belt to snap? ( again, im not too mechanically inclined).

thanks again for all the input.

 

Water Pumps being bad will cause the Timing Belt to go bad too..

However, If it IS coolant, then you have a head gasket leak..

 

OK hold your hand in front of the exhaust pipe tommorow. Does it feel all clammy and warm. does the smoke disipate right away. Then it's coolant

If the smoke lingures down the street it's oil, You may have a residue on the pipes.

If you think it's coolant try the $30 bottle of barsleak liquid stopleak. That will seal it up with glass. It ought to hold you for a while.

Like Jim is saying the pump does not make your car burn coolant head gaskets do. What makes you think your waterpump is bad?

 

White smoke = as the guys said.
Greyish smoke on cold start - cold days (until car warms up good) = just condensation droplets.
Is it really white or grey?
Were you just led to believe it smells "sweet", or it really does smell sweet?

P.S> The engine should get pretty warm even after a drive on a cold day. How cold of a day you're talking about?

 

ok, the thought process that i'm going through, regarding the water pump, is a long story.

About, almost, two years ago, i got my timing belt changed, with the water pump. After the guy changed it I got a check engine light that came up as 'cam position sensor'. The guy said it was something else or for some other reason but another person told me he didn't lock the cams right after he did it.

I never did anything about it and drove around for a year and a half and then took it to another mechanic for some other stuff about 6 or 7 months ago who tried to lock the cams right but then suggested i get the timing belt done again otherwise it will go bad ( he made me listen to the pullies with some sthethscope like thing cause the engine was making a rattling noise).

The car is still making the noise, but after he suggested to change the belt i still couldnt afford it so i still just drove around. the smoke started a few months ago and he told me about the belt in like march (maybe).

All this worry about the belt snapping on me plus the smoke issue and coolant just made me come to the thought that it could be the water pump.

sorry for the long story but that is how my assumptions came about. lol