Despite having a DPF, my car's blowing a bit of smoke at the moment. I am fairly close to the answer now, but let me go over a few details that led me along the way.
We noticed that under mild acceleration, boost would gradually build up to normal levels, but when trying to get moving from a stop (and we were towing the caravan when this started) rather than accelerate, we'd just fill the road behind with smoke. Yes, I'm sure this isn't doing the DPF very well.
I first thought that it was either of two possibilities (not discounting other possible causes, but as usual starting with the least expensive). First, a cracked/loose vacuum hose or a faulty actuator control solenoid. I should add that about a week ago, I had to stop driving because I was suddenly creating a large plume of blue smoke which disappeared fairly quickly. So, today ...
I decided that the blue smoke - which hasn't come back - may have been caused by a bubble of oil that was ejected from the intercooler. That may have been the case. After removing the grille and the two bolts that hold the intercooler plus the two hose clamps holding the hoses onto the plastic end "tanks", the intercooler came out fairly easily. Inside was completely black.
The fifth wash with petrol wasn't as black as the first four. I suspect I could have washed it some more, but a look inside showed nice clean metal so I considered the task finished for now.
Here's a shot of the intercooler on the top of the engine bay.
I then proceeded to replace all of the vacuum hosing. There are several pieces to replace, described as follows:
1) From the vacuum pump on the right-hand side of the engine (just below the fuel filter) to the tube furthest from the electrical connection on the solenoid. This passes over the top of the engine engaging several clips to hold it in position (both to keep it off the engine and to stop it rubbing against stuff).
2) From the turbocharger actuator to the next tube in towards the electrical connector on the solenoid.
3) From the last (third) tube on the solenoid to the air intake.
I had spare tubing from 3m of 3mm tube. Starting the engine and watching the actuator working proved that I'd at least put it back together in the right order.
So with a clean(ish) intercooler and the vac hosing replaced and tested (obviously the solenoid's working too, or the actuator wouldn't have been moving at all) I expected to be able to drive the car and not experience any smoke.
Nope.
Similar cause and effect. If I built boost slowly, she'd behave. If I tried to belt her, she'd develop about 6psi and no more. Back off, let the turbo spool up gradually - full boost again.
I can only think now that there are two things happening there. First, when over-throttling and seeing the boost stall, it's likely that there's not enough combustion occuring (not enough air) to drive the turbocharger any harder - so it's an endless loop. It's overcome by backing off and letting the engine build up gradually.
It leads me to think that there are only a couple of possibilities now.
1) Another sensor (boost most likely) is faulty. I'm thinking not, because once the turbo comes up to speed, everything behaves normally.
2) The turbocharger is unable to spool up quickly enough. This might be a sticky bearing, or turbine blades that are either caked so badly with muck they're unable to be propelled properly by the exhaust.
So tomorrow I'm going to start examining the turbocharger. Or do the lawn. Or both. I may have to replace the bearings in it - it's a job I might get someone else to actually do, I'm still in considerable pain after falling from a ladder and I don't think I want to work on something that needs to spin near 100,000rpm to work properly.
We noticed that under mild acceleration, boost would gradually build up to normal levels, but when trying to get moving from a stop (and we were towing the caravan when this started) rather than accelerate, we'd just fill the road behind with smoke. Yes, I'm sure this isn't doing the DPF very well.
I first thought that it was either of two possibilities (not discounting other possible causes, but as usual starting with the least expensive). First, a cracked/loose vacuum hose or a faulty actuator control solenoid. I should add that about a week ago, I had to stop driving because I was suddenly creating a large plume of blue smoke which disappeared fairly quickly. So, today ...
I decided that the blue smoke - which hasn't come back - may have been caused by a bubble of oil that was ejected from the intercooler. That may have been the case. After removing the grille and the two bolts that hold the intercooler plus the two hose clamps holding the hoses onto the plastic end "tanks", the intercooler came out fairly easily. Inside was completely black.
The fifth wash with petrol wasn't as black as the first four. I suspect I could have washed it some more, but a look inside showed nice clean metal so I considered the task finished for now.
Here's a shot of the intercooler on the top of the engine bay.
I then proceeded to replace all of the vacuum hosing. There are several pieces to replace, described as follows:
1) From the vacuum pump on the right-hand side of the engine (just below the fuel filter) to the tube furthest from the electrical connection on the solenoid. This passes over the top of the engine engaging several clips to hold it in position (both to keep it off the engine and to stop it rubbing against stuff).
2) From the turbocharger actuator to the next tube in towards the electrical connector on the solenoid.
3) From the last (third) tube on the solenoid to the air intake.
I had spare tubing from 3m of 3mm tube. Starting the engine and watching the actuator working proved that I'd at least put it back together in the right order.
So with a clean(ish) intercooler and the vac hosing replaced and tested (obviously the solenoid's working too, or the actuator wouldn't have been moving at all) I expected to be able to drive the car and not experience any smoke.
Nope.
Similar cause and effect. If I built boost slowly, she'd behave. If I tried to belt her, she'd develop about 6psi and no more. Back off, let the turbo spool up gradually - full boost again.
I can only think now that there are two things happening there. First, when over-throttling and seeing the boost stall, it's likely that there's not enough combustion occuring (not enough air) to drive the turbocharger any harder - so it's an endless loop. It's overcome by backing off and letting the engine build up gradually.
It leads me to think that there are only a couple of possibilities now.
1) Another sensor (boost most likely) is faulty. I'm thinking not, because once the turbo comes up to speed, everything behaves normally.
2) The turbocharger is unable to spool up quickly enough. This might be a sticky bearing, or turbine blades that are either caked so badly with muck they're unable to be propelled properly by the exhaust.
So tomorrow I'm going to start examining the turbocharger. Or do the lawn. Or both. I may have to replace the bearings in it - it's a job I might get someone else to actually do, I'm still in considerable pain after falling from a ladder and I don't think I want to work on something that needs to spin near 100,000rpm to work properly.
