The car was running fine until recently when it started to stall in the mornings
during warm up. Then I hit what felt like two fuel pump shut offs under boost.
Got worse, felt likea big air leak, pulled codes and had a 2341. I have pressure
tested the entire intake from the output of the turbo, it will sit and hold 10psi.
However when I test from the MAF through the turbo it doesn't hold pressure
and I can hear air bubbling in the sump. In previous pressure tests (looking for
leaks) the pressure at the MAF remained constant and if any air leaked past
the tubo seals it was minimal. Can the oil seal on the cold side housing fail and
cause air to leak at the turbo? This doesn't make send to me as the oil would
be at 80psi and it should spray in to the cold side if the seal was damaged? I
have also tested the MAF to turbo hose independently and it holds pressure.
There is no play in the turbo and it is fairly new, maybe 50,000kms. I also
swapped the MAF with a known good one, still got the 2341 code, also the
plugs were very black indicating very rich. O2 sensor seems to be cycling
normally. Everything points to a big boost leak but apart from the turbo
the intake piping and vacuum lines seem leak free.
Any thoughts or things to test greatly appreciated.
p.s. I was going to pull the wastegate cap to look at the diaphram but I still don't understand why so much air is leaking through the cold side turbo housing to the oil
lines....
thanks, Mike Hopton
during warm up. Then I hit what felt like two fuel pump shut offs under boost.
Got worse, felt likea big air leak, pulled codes and had a 2341. I have pressure
tested the entire intake from the output of the turbo, it will sit and hold 10psi.
However when I test from the MAF through the turbo it doesn't hold pressure
and I can hear air bubbling in the sump. In previous pressure tests (looking for
leaks) the pressure at the MAF remained constant and if any air leaked past
the tubo seals it was minimal. Can the oil seal on the cold side housing fail and
cause air to leak at the turbo? This doesn't make send to me as the oil would
be at 80psi and it should spray in to the cold side if the seal was damaged? I
have also tested the MAF to turbo hose independently and it holds pressure.
There is no play in the turbo and it is fairly new, maybe 50,000kms. I also
swapped the MAF with a known good one, still got the 2341 code, also the
plugs were very black indicating very rich. O2 sensor seems to be cycling
normally. Everything points to a big boost leak but apart from the turbo
the intake piping and vacuum lines seem leak free.
Any thoughts or things to test greatly appreciated.
p.s. I was going to pull the wastegate cap to look at the diaphram but I still don't understand why so much air is leaking through the cold side turbo housing to the oil
lines....
thanks, Mike Hopton