Lack of performance - 2.0Dti

[TonyP2020]

It’s been a steep learning curve over the past few days, trying to sort the poor performance of my 2003 2.0Dti, so I thought that I would put my observations on here to help others.

Making sense of what is happening is not easy.

The engine was running but the car was gutless, and needed to be 1 gear lower at normal speeds except on the Motorway.

It started with :

P1105 (FA) Barometric pressure not plausible with boost pressure.

P0105 (FA) Barometric pressure not plausible with boost pressure.

Basically the Engine Control Unit is seeing a mismatch between Barometric Sensor and Boost Pressure Sensor.

Readings taken from my car with the above problem.

Barometric Sensor reading 102Kpa.
Normal Air Pressure is 100kpa.

This reading varied slightly over a few days, due to the weather.
The Barometer Sensor is mounted behind the Airfilter Box, and is held by one bolt on a mounting bracket.

Boost Sensor Command Between 110Kpa to 140Kpa.
Boost Pressure Sensor Between 98Kpa and 102Kpa when engine revved.

The Boost Sensor readings never matched the Boost Sensor Command pressure.
98Kpa is actually a slight vacuum compared to atmosphere pressure.

The Boost Pressure Sensor is mounted on the alloy inlet manifold.
The Boost Pressure Sensor is also the Intake Air Temperature Sensor.

Air Intake Temperature Sensor. 50 Degrees C after standing for a while, dropping lower when the engine is started and cold air is drawn in.

I bought a new Boost sensor, £40, but it gave the same readings.

Then I checked for any split/loose turbo boost hoses, but found none. I even put a 20 year old portable hoover vacuum, which has a blow facility, onto the hoses after the turbo and it all seemed airtight.

I checked that the turbo waste gate is being pulled shut. It is vacuum operated, but controlled electrically. The black plastic vacuum solenoid is behind the air filter box. There are 2 vacuum pipes going to the solenoid, one from the vacuum pump and the other going to the wastegate solenoid.

To test the waste gate, with the engine idling, pull off the black vacuum pipe without the yellow marking. If you follow the pipe you have pulled off, it goes to a metal pump/solenoid with a shaft going into the turbo. The wastegate is normally open but is pulled closed by the shaft.
Observe the push rod below and left of the turbo. With vacuum it should pull the rod back into the metal solenoid. You can also do this my hand, but beware the turbo will be hot.

If the wastegate doesn't move, then you might have a vacuum problem. Check all the vacuum pipes and rubber ends for any obvious splits. The usual problem is the rubber connection pieces on the control solenoids, or bottom of the Vacuum Pump, perish.

I had already changed all the vacuum pipes. It only cost a few pounds, and I used black 3mm silicon. This silicon will stretch over all the connections.

If they are OK, then check it's not the brake servo leaking. Disconnect the Brake Servo Pipe from the Vacuum Pump. The vacuum pump is mounted on the Top RHS of the engine.
Pull of the large black pipe, (push the button on the end of the pipe) and stick your finger over the pipe port, while checking to see what the waste gate does.

If you have a vacuum gauge and can check the vacuum, it is supposed to be a minimum of 0.7 Bar or 8psi.

You can also use the vacuum gauge and work your way through the system checking to make sure you're getting a good vacuum right up to the control solenoid.

I also learnt that if the Vacuum solenoids are chattering then they need cleaning inside.
It is not easy to take the top of the solenoids off, and if you do manage to dismantle them they will not look very nice when re-assembled.

My car has 2 solenoids, 2.2Dti’s have 3 or 4, I think. They are about £50 each.

Removing and dismantling the Vacuum Pump is not too difficult. I found it was full of oil, which was strange as there is a spring leaf (not sure if that’s the right name) at the bottom of the pump. The oil can get in from the Camshaft, and I think this spring leaf is to let the air and oil out. Both vacuum connections have one way valves in them, and will benefit from being blown out.

Brake Servo’s can leak and this will have an effect on the braking and the vacuum solenoids.

So after all this I still had a car that was working but sluggish, with a lack of boost pressure.

I dismantled the turbo without removing it from the car. The inlet (cold air) side had oil sprayed inside, the exhaust side was pretty mucky with soot.

The middle of the turbo, where the bearings are, has a dedicated oil feed, and the oil sprayed inside the inlet side must have come from that oil feed, which means that the oil is getting past the seals.

The spinning bits of the Turbo looked ok, nothing broken, but very stiff. Cleaning the exhaust side out with brake cleaner made a small amount of difference, but the impellors were not free to turn easy.

So I put it all back together, but it was still the same, with maybe slightly more boost.

So my Turbo, a Garrett GT15, is now on its way to Blackpool to be rebuilt by http://www.turborebuild.co.uk/

Estimated cost £175 to £275.

[macdad]

I'll be watching your progress with interest m8,as i have a few issues with mine at present,it' keep jumping into limp mode every week or so,tried all the obvious ones without success.

[TonyP2020]

Hi Macdad, checking the turbo is actually not that difficult.

4x Torx bolts removed lets you check the dirty end of the turbo. The exhaust moves out of the way due to the flexible pipe in the exhaust.
The impeller is tiny, not much bigger than a £2 coin.
You can also see the round waste gate.

4x 10mm Bolts plus remove 2 hoses removed lets you check the clean end of the turbo. The blades on the turbo can be seen, none broken luckily.

As you can see, oil in the clean end, sooted up in the dirty end.

[macdad]

So ? is yours cream krackered then Tony,i see your sending it off to Blackpool.

ps Did you clean the black soot off after pic,might do mine if it sqeezes a few more bhp out of her.

[TonyP2020]

Yes, sprayed it with lots of Brake Cleaner, but it made no difference.
It is probably worth cleaning the soot out, checking how well the turbo spins, and if the waste Gate operates OK.