Audi RS2 Black Cloud Issues

[fvegars2]

Hi, im from Costa Rica and a proud owner of a 95 Audi RS2, recently I have been experiencing issues with the car, it would stutter under acceleration, leave a huge black cloud and wouldn't want to rev past 4k rpm. It has gotten to a point where it is so bad that it sometimes won't even want to move and even shutting off making the car undriveable. Any recommendations greatly appreciated thanks!

[K Simmonds]

Black smoke combined with "stuttering" would suggest un-burnt fuel, which is normally due to a boost leak, ie a leaking/damaged inlet hose, can you perform a leak test?

However a "huge" black cloud sounds more like a problem with the turbocharger letting oil past it's seals/rings, though the smoke would have a slightly blue hue to it... If I were you I'd pop the inlet boot off and check shaft play...

It could also be an issue with the PCV system being blocked up and not allowing the crankcase to ventilate correctly.

Not the most specific of advice I know but at least it gives you some pointers, the search function on here is your friend.

[fvegars2]

Black smoke combined with "stuttering" would suggest un-burnt fuel, which is normally due to a boost leak, ie a leaking/damaged inlet hose, can you perform a leak test?

However a "huge" black cloud sounds more like a problem with the turbocharger letting oil past it's seals/rings, though the smoke would have a slightly blue hue to it... If I were you I'd pop the inlet boot off and check shaft play...

It could also be an issue with the PCV system being blocked up and not allowing the crankcase to ventilate correctly.

Not the most specific of advice I know but at least it gives you some pointers, the search function on here is your friend.

Thanks! It recently had a big boost leak but it was fixed like 2 weeks ago, its been having this issue for about 3 months now (the car isn't the daily driver only 77,000km), but it is really terrible now. Its a lot of unburnt fuel, the gas mileage has been horrible. I will have the pcv checked and notify any advances here.

Thanks

[Bowie69]

Could even be the coolant temp sender on the back of the head, making it too rich, and the richness causing the misfires.

It is easy to check, either plug in through diagnostics port, or the figures for testing with a multimeter are in the workshop manual.

[fvegars2]

Could even be the coolant temp sender on the back of the head, making it too rich, and the richness causing the misfires.

It is easy to check, either plug in through diagnostics port, or the figures for testing with a multimeter are in the workshop manual.

I will get it checked today! I think I discovered a small coolant leak that might be coming from that sensor. Will keep you posted

[fvegars2]

So, been checking the car today, a vacumm that goes to the fuel pressure regulator seems to be stripped. Now, does anyone know where does the wastegate vacumm line go to?

[SteveH]

So, been checking the car today, a vacumm that goes to the fuel pressure regulator seems to be stripped. Now, does anyone know where does the wastegate vacumm line go to?

It doesn't connect to anything and should be open to air.

[fvegars2]

It doesn't connect to anything and should be open to air.

Yep, thanks! the coolant sensor was really dirty seems to be working fine now, and the fuel regulator vacuum line was damaged, will repair it tomorrow and hopefully it will be the end of the issues. Its a shame because the car rarely sees the road (around 300km every year) so its been having this issue for quite a while now and I didnt pay attention to it as I have other projects as well but really hoping to get it back up and running now as I have a Porsche road trip this weekend

[newsh]

A 1Bar pressure test of the inlet tract from the MAF hose will show any boost leaks, it would have found the FPR hose leak and you will probably find most of the small diameter vac hoses are past their best. I would replace all the small bore piping with new stuff, either the original braided cotton over rubber or silicon.

[Rikki Kitto]

Shame it doesn't do much mileage these cars need driving

[fvegars2]

A 1Bar pressure test of the inlet tract from the MAF hose will show any boost leaks, it would have found the FPR hose leak and you will probably find most of the small diameter vac hoses are past their best. I would replace all the small bore piping with new stuff, either the original braided cotton over rubber or silicon.

Yes! Currently replacing all vacuum lines. Quick question. Where does the Fuel Regulator vacuum line go to? The line was shredded and we don't where does it go.

[fvegars2]

Shame it doesn't do much mileage these cars need driving

I agree! It needs to see more road!

[SteveH]

Yes! Currently replacing all vacuum lines. Quick question. Where does the Fuel Regulator vacuum line go to? The line was shredded and we don't where does it go.

Most of the vac lines head to the inlet manifold. I doesn't matter which connector as they all have vacuum/boost at the same pressure.

[fvegars2]

Most of the vac lines head to the inlet manifold. I doesn't matter which connector as they all have vacuum/boost at the same pressure.

Thanks!! Hooked it up and its back up and running amazing! Problem was the shredded fuel regulator vacuum line

[newsh]

Thanks!! Hooked it up and its back up and running amazing! Problem was the shredded fuel regulator vacuum line

Excellent!