Came to me on recommendation. Car had been purchased privately a few days before.Showing mileage of 150k. Considering mileage condition was remarkable.Customer told me that for the first 5 miles the performance was so erratic that he was very concerned in his ability to avoid having an accident in slow moving traffic.

We took it for a short test drive and even with an engine temp of 80c you could feel a lag between throttle opening and engine response.Once it did respond the torque was tremendous so this fact alone indicted that engine mechanical condition was probably very good. By the way the vehicle was test driven on purchase with a fully warmed up engine. I wonder why?.

Anyway on return to the workshop even without scanner data i had come to the conclusion that the symptoms indicated the variable vanes in the turbo had carboned up.To be honest this is now becoming a potential epedemic. I told the customer what the potential options were with emphasis on sticky vanes.Car was left with me to be collected late afternoon so customer could get to his night shift job.My favourite for a quick scan is the Autel md802 All Systems model. Its cheap and very user friendly with a very useful graphing mode and also can overlay two graphed parameters together.

At idle of 804 rpm the following data was noted Boost pressure 8.3% Acel position D 8.62% Acel position E 8.23% Turbo var vane 8.1%.As you can see all 4 pids are to all intents and purposes the same.All other data pids looked good as well.My next move was to graph the MAF and Turbo variable vane as an overlay. Blipping the throttle produced enough of a mismatch between the two to confirm my initial diagnosis.

Without going into all details for fear of boring you out came the MR MUSCLE oven cleaner.This was introduced into the exhaust upstream of the turbo.It is only regarded as a temporary fix but if it is carried out several times it can delay any major expenditure .As long as the customer is fully aware of what the potential future implications could cost then they can either sell it and buy a petrol car or just keep bringing it back for more treatment.

After treatment the car was test driven and during this time a careful eye was kept on the MAF and Var vane graphs. Performance was very good and both graphed parameters coincided on the overlay. Customer came back in after a week and reported that fingers crossed all was well.Diagnosis time 15 mins Decarb vanes 1 hr. I admit that the decarb of the turbo vanes is not a permanent fix but having been in the position of a mortgage, kids and a fixed income i can sympathise with my customers plight.The modern diesel can quite easily financially cripple any unsuspecting owner but the public are becoming increasingly aware of diesel downsides.

What you can!t argue with is that when a modern diesel is running well the torque produced between 1500-2750 rpm far exceeds any petrol engine but at what cost to the customer once a few thousand miles have clocked up.

Alexander