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View Full Version : D5 185 Polestar peak boost pressure? and euro4 turbo actuator?



a lex
Saturday 25th July 2015, 18:16
Car is a 2010 XC90 D5 185 with the Polestar software (205/450) that has been on there since new.

In the last two weeks ive been getting repeated ECM codes for MAF and Lambda signal too low errors, and a hesitation (and yellow triangle of doom) during acceleration. No limp mode though.

Ive replaced the MAF, Lambda sensor and MAP sensor, but to no avail - the problem is exactly the same.

Ive been out with VIDA and logged the Manifold pressure. During the areas circled in red are where I experience the sudden dip/lack of power and the DTCs are created:

http://img.photobucket.com/albums/v70/alexisbad/volvo/map%20graph%201.jpg (http://smg.photobucket.com/user/alexisbad/media/volvo/map%20graph%201.jpg.html)

http://img.photobucket.com/albums/v70/alexisbad/volvo/map%20graph%202.jpg (http://smg.photobucket.com/user/alexisbad/media/volvo/map%20graph%202.jpg.html)

http://img.photobucket.com/albums/v70/alexisbad/volvo/map%20graph%203.jpg (http://smg.photobucket.com/user/alexisbad/media/volvo/map%20graph%203.jpg.html)


There is an accumulation of oil around the bottom turbo pipe under the car (quite common) and a thin film of oil and deposits around the bottom of the IC, particularly lower passengers side....

http://img.photobucket.com/albums/v70/alexisbad/volvo/DSC_0153_1.jpg (http://smg.photobucket.com/user/alexisbad/media/volvo/DSC_0153_1.jpg.html)

http://img.photobucket.com/albums/v70/alexisbad/volvo/DSC_0159.jpg (http://smg.photobucket.com/user/alexisbad/media/volvo/DSC_0159.jpg.html)

This oil discolouration was not there two weeks ago:

http://img.photobucket.com/albums/v70/alexisbad/volvo/oil%20patch%20bar.jpg (http://smg.photobucket.com/user/alexisbad/media/volvo/oil%20patch%20bar.jpg.html)



At peak boost the turbo is delivering around 25psi. This is pretty high, right? But does anyone know if its normal for a Polestar mapped car? Overboosting would certainly explain the oil on the turbo piping and gradual death of the IC.

Secondly, do the euro4 185 cars have a turbo governor / actuating solenoid/valve like the e3 163cars, or is it all electronically driven? What else could be causing the o/boost (if indeed 25psi is too high).....

Thanks for any insight. The car is in the garage Monday morning for diagnosis and im due to drive it around Europe at the end of the week. Great timing!