Car is a 2009 Clubman D. Turbo was replaced in December. The problem is as follows. On the intake side of the turbo (i.e. the compression side) the pipe that feeds air to the turbo is not firmly connected; for example I can slide the air intake tube off the turbo inlet. It hasn't fallen off during driving and seems to stay in place, but I can definitely slide the pipe off the turbo.

In this case, the connection comes after the MAF in the airflow sequence. I believe that at the intake, before the air enters the turbine, this is vacuum (i.e. negative) pressure. So I would assume that there is the possibility that unmetered air is entering at this joint. It would make sense that this airflow isn't being picked up by the MAF, hence unmetered air entering the turbo. I'm thinking this would result in a lean running condition. Would this be correct? Could it also lead to a loss of power?

If so, what are the symptoms of lean burning in a diesel engine? There is no smoke coming out the tailpipe and the tailpipe is sparkling clean - no soot whatsoever. So I'm a little bit confused as to whether or not this loose pipe is actually a problem.

In summary:

1) Is this (potential) leak causing unmetered air to enter the turbo?
2) Is this unmetered air resulting in a lean running condition?
3) Does this pipe actually need to be air tight (i.e. is the loose pipe actually a problem?)
4) What symptoms (this is a diesel engine) should I be observing if this is indeed the case?

Thanks. I guess the fix is pretty simple, replace the orange sealing gasket and put on a better clamp, but I'm wondering if I should get it resolved now or can I wait a month until the car goes in for service?

 

Pretty common for that connection to go. Happened to me recently, the pipe ended up cracking the second i touched it because it had dried up and become so brittle. The rubber insert would slip out from the end of the tubing. If yours isn't brittle, I'd suggest taking the insert out, and using MAF cleaner (safe for the plastic/rubber hose) and spray all the mating surfaces at the end of the pipe. This seemed to help hold it on until I got a new one. However, yours might still be OK and this could be a fix for you.

To answer your question, my car would spike to 18psi (tuned), then would drop off to as low as 9psi at times.. upon replacing this pipe the problem disappeared.

 

Diesels are different from gasoline (petrol) motors in that they can tolerate lean mixtures. In fact, in older diesels, the mixture is the primary control worked by the throttle pedal. Older diesels have no throttle valve, you get more power by richening the mixture and less power by leaning it out.

That would lead me to guess that you'd be fine letting it go for a while. You'll get less power than you might, and you may have higher emissions than if everything were working correctly, but the engine probably will hold up to it fine.

Then again, how much risk are you willing to take from some guy on the internet saying "it will probably be OK"? :D

 

Thanks for the photo. I looked at mine at home after I got home from work. Seems the pipe integrity is fine. The little orange gasket/seal could be okay too, but I'm not sure. Seems to me like the clip that holds it in place isn't strong enough to form an airtight seal.

Looks like it should be easy enough to fix with a new clamp and preferably a new gasket. Looks to me like they reused the clamp and gasket which, in my opinion, would be a no-no.

[QUOTE=SooperCuperErik;3475234]Pretty common for that connection to go. Happened to me recently, the pipe ended up cracking the second i touched it because it had dried up and become so brittle. The rubber insert would slip out from the end of the tubing. If yours isn't brittle, I'd suggest taking the insert out, and using MAF cleaner (safe for the plastic/rubber hose) and spray all the mating surfaces at the end of the pipe. This seemed to help hold it on until I got a new one. However, yours might still be OK and this could be a fix for you.

To answer your question, my car would spike to 18psi (tuned), then would drop off to as low as 9psi at times.. upon replacing this pipe the problem disappeared.

 

Thanks. This makes good sense. The only thing I'm afraid of is if the pipe pops off during driving. God forbid I get anything sucked into the turbo. The turbo itself is only 3 months old!

Seems to me that the engine is running lean. In my mind, I see that the loose pipe is drawing in air after the MAF, so the MAF is reporting wrong airflow values to the ECU.

The car indeed is running flat with less power. Sometimes it feels naturally aspirated. Occasionally if I blip the throttle and downshift, the car kind of hesitates and if I didn't know better I'd say it would almost stall, but then it recovers. It has never stalled and I have the impression it won't. I'm wondering if it's some kind of back pressure or something where air is pulled in from the leaking pipe.


I'm wondering if I'm also getting higher exhaust gas temps. Reason being is that I looked at my tailpipe and there's a small spot that looks like it's been really heated up.