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hi i have been struggling with my c220 cdi for some time now, vehicle lost power last year November, vehicle felt like it was not boosting, and it did not want to rev past 3000rpm but it would drive to around 80 km/h but struggling i would have to drive it in manual mode to go up a hill, first suspect was turbocharger.
Once i stripped the turbo i found the bearing was actually seized and the vnt system was slightly carboned up.
turbo was sent in for reconditioning and now the compressor and turbine wheel were spinning freely and the turbo was put back into the car
vehicle still had no power this time I got a fault code (check component Y100/1 right charge pressure positioner signals fault) - permanent
when I checked actual values on idle or when the idle is raised the boost value and air mass values our out as per screen shots below, if i rev the car and switch the vehicle on and off the car would then allow we to rev past 3000rpm and vehicle boosted briefly then it would go into a limp again.
I removed the catalytic convertor to see if it was blocked and the car drove the same with no power and not revving past 3000RPM
I checked the wiring on the right charge pressure positioner, i was getting ground power and if I applied a ground on the signal wire the actuator moved up and down fine even though there was a fault code for signal faulty
I then proceeded to replace the right charge pressure positioner, which is the electronic turbo actuator, I was able to buy a new "Hella" unit from a turbo shop, I fitted the new unit onto the turbo.
now the vehicle was running rough and could not rev up at all or go past 20km/h and had excessive black smoke, after checking with the supplier they advised that the new unit needs to be programmed with a diagnostic machine to learn its stop and start values
i borrowed a launch diagnostic machine and it did not have a function to program this, i called a merc tech out with a start diagnosis and he was not able to program this either, i concluded that possibly for this model (w203) this was not possible
I then put the old charge positioner back and the vehicle was at least able to drive but would not rev past 3000 rpm but it was somewhat useable if i did not need to go past 80 km/h.
I then decided to clean the egr system and check boost pipes for any leaks, i found some carbon in egr system and cleaned it out and no issues on boost pipes or intercooler
vehicle drove slightly better but still the same
I am not sure what else to do here, can anyone recommend what I should look at? i dont want to keep replacing parts and not getting anywhere, i was thinking there might be an issue with the air mass meter but was not able to locate a used one to test.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
