What can cause compressor surge? (159 1.9 JTDm)
Chaps, I need help here.
Been trying to diagnose throughout this the forum this but no answers so far. Very briefly, symptoms are:
1 - if turbo is in a situation of high pressure (like going up a hill), if I release the throttle, I get triple "swoosh" sound and the car shakes slightly;
2 - on 1st and 2nd gear, taking it to 3000rpm can cause the surge as well, a bit more evidently;
3 - sound seems to come from middle to right-hand area of the engine bay;
4 - on any gear from 4th-6th, turbo responds promptly, to overtake, etc;
5 - WOT takes the pressure gauge to max 1.5, then drops (which I believe to be normal)
6 - when disconnecting the MAF, symptoms disappear, which I understand is because the ECU defaults to average readings, bypassing the missing MAF.
About (2), engine feels slightly overworked to get to speed, which is why I sometimes stretch it that far (not often). Not sluggish, but nearly.
What has been checked:
- EGR (had a failure warning): replaced with a new genuine one, including official rectangular restrictor gasket
- MAP sensor: cleaned
- MAF sensor: cleaned (was hardly any dirt in there anyhow)
- vacuum pipes: checked, no leaks
- injectors: checked, all within tolerances
- glow plugs: checked, all in order
- DPF: regens normally
So what else do I need to look at before I am dealing with a failed turbo?