Urgent Help Needed: C220d 2016 Turbo boost lack/loss

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harrison0401

New Member
Joined
Feb 10, 2022
Messages
4
Location
Coventry
Car
E220
Code: P029900 (Turbo 1 boost low) P228100 (leak between MAF and throttle) P22C872 (turbo waste gate stuck,not close)

Day 1: While driving, I noticed a recurring rattling noise accompanied by a boost loss during acceleration, followed by a return of boost at higher RPMs. After some time, achieving high RPMs became increasingly difficult, and manual downshifting was no longer possible. Upon stopping, I located the source of the rattling noise to the left side of the engine (turbo), with the engine running smoothly. OBD diagnostics revealed fault codes related to intake and turbo valve issues (presumably referring to the waste gate): 1. Detected pressure leakage between throttle valve and MAF 2. Turbo valve stuck. Even after clearing the fault codes, the problem persisted, with boost sometimes normal and other times absent. While driving, I monitored the waste gate opening data flow, which remained at around 50% regardless of throttle input (5% when engine is off).

Day 2: Experienced turbo lag at high RPMs, with engine continuing to receive throttle input for 0.5 seconds after releasing the pedal. Concerned, I gave a sudden throttle input while stationary, causing the engine to accelerate uncontrollably. I had to turn off the engine by removing the key. However, subsequent attempts to start the engine failed initially, with the starter functioning but the engine refusing to start. After approximately 10 attempts, the engine started but emitted blue smoke from the exhaust. Light throttle input was normal, but at 3k RPM, the engine again accelerated uncontrollably. Even after removing the key, the engine continued to operate at full load for about 5 seconds before stopping. I'm now afraid to attempt another start.

Initially, I suspected a stuck waste gate causing turbo pressure loss. However, the emergence of significant blue smoke and uncontrollable engine RPMs has left me deeply concerned.

Has anyone experienced similar issues before?

Thanks.
 
Most modern diesel engines have variable vane Turbochargers and no waste gate.

The smoke and runaway engine speed does sound like a failed Turbocharger seal allowing oil to be drawn through and burnt.
 
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Most modern diesel engines have variable vane Turbochargers and no waste gate.

The smoke and runaway engine speed does sound like a failed Turbocharger seal allowing oil to be drawn through and burnt.
Thank you for your reply. After experiencing a second runaway, the car now fails to start. Attempting to start results in a black screen, seemingly due to insufficient voltage, and the starter motor struggles to rotate the engine, which turns slowly and irregularly. This doesn't sound like a good sign. I checked the oil dipstick, and the oil level hasn't changed, with no visible metal fragments. Upon opening the oil cap, there was no apparent wear. Can a runaway damage the engine? Does a damaged turbo oil seal require a rebuild or a complete turbo replacement? Thank you.
 
Thank you for your reply. After experiencing a second runaway, the car now fails to start. Attempting to start results in a black screen, seemingly due to insufficient voltage, and the starter motor struggles to rotate the engine, which turns slowly and irregularly. This doesn't sound like a good sign. I checked the oil dipstick, and the oil level hasn't changed, with no visible metal fragments. Upon opening the oil cap, there was no apparent wear. Can a runaway damage the engine? Does a damaged turbo oil seal require a rebuild or a complete turbo replacement? Thank you.
Unsure why the battery may no longer have sufficient charge? Did you have any battery warning lights before?

A runaway engine can cause a lot of damage but it may not have done so if it was of fairly short duration. Of course it may also have had an injector sticking open supplying too much fuel.

Turbochargers can be rebuilt, exchange units are rebuilt ones. They should have new seals and bearings as a minimum.

What ever the problem is it needs recovering for investigation.
 
If its run away due to turbo the smoke would start to get to the point of being like fog as the engine starts to run on engine oil instead of fuel due to turbo seal failure, it'll draw it up through the intercooler so you could drop a intercooler lower pipe and see what comes out, it'll be oil damp anyway due to engine breather but if any oil pours out it'll be your turbo, a manual trans can be stalled autos will carry on till something gives. The struggle to turn over with battery drain could be partial sieze if its run away too long. Dont try to run it till its been checked out.
 
"a manual trans can be stalled autos will carry on till something gives."

How do you stop a runaway in an automatic?
 
If this is twin turbo, it has a wastegate...
yeah, runaway sounds like engine burned oil after shutdown
 
Block the air intake.
Agree totally, your not running on fuel and no electric shut off. In the spare of the minute after the initial panic and a blank mind what to do you have to think where your best access is to the intake, then if you have a rag large enough to block completely it should start to shut down but by the time you got to this point its probably gunna be all over. As said with manual trans you can stall as soon as things start to get wild and save the engine. I've replaced a turbo on a mk2 Octavia that run on oil and the oil gets everywhere, luckily the driver had the sence to stall it with some serious clutch abuse.
 
Thank you for your attention. I will be taking the car to the garage next week. Since the engine automatically shut down within a few seconds during both runaways, I am wondering if the engine really seized. As I don't have a charging device, today I tried to start the engine with a low battery to see if the crankshaft would turn. I could see the belt being driven to rotate about 45 degrees each time I ignited, then it stopped, which seems like it’s not stuck. If the belt can rotate, does it mean the engine has not seized?
 
Thank you for your attention. I will be taking the car to the garage next week. Since the engine automatically shut down within a few seconds during both runaways, I am wondering if the engine really seized. As I don't have a charging device, today I tried to start the engine with a low battery to see if the crankshaft would turn. I could see the belt being driven to rotate about 45 degrees each time I ignited, then it stopped, which seems like it’s not stuck. If the belt can rotate, does it mean the engine has not seized?
Without a proper inspection it is just guess work. Hopefully it will not be a catastrophic failure.

Please let us know what is found when it is inspected 👍
 
Usually the ECU commands the the throttle to be closed when an overspeed is detected. No need to shove a rag in the intake any more.
 
Usually the ECU commands the the throttle to be closed when an overspeed is detected. No need to shove a rag in the intake any more.
I have thought that Diesel engines do not have a throttle?
 
I have thought that Diesel engines do not have a throttle?
They have throttle, but it's used very differently to a petrol engine.

Yes, in a Diesel under normal operation the throttle is fully open, speed is controlled by fuel flow. The throttle is used for other purposes though:

EGR flow relies upon pressure differential between exhaust and intake. At idle that differential may be too low, so throttle can be partially closed to create a depression in the intake. This creates a bigger differential, allowing the desired EGR flow.

During engine shut off, just before the engine stops, it's shut and opened just after after. This gives a nice smooth stop with no shake.

If an engine overspeed is detected, throttle is closed, restricting air. No air, no combustion.

Used to intentionally reduce volumetric efficiency of the engine, Can ube useful during a static regen when you want to increase heat.

Mercedes may not use for all these scenarios but some other manufacturers do.
 
I know what you mean, the vectra 1.9 cdti has a electronic butterfly flap on the inlet manifold where the intercooler pipe fit, looks like a carb throttle body but all it does is close at idle to make a smooth instant shut down, not strong enough to close on full chat with no fuel shut of though.
 
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