# TFSI misfire diagnosed now they want to take engine out



## Rosie SA (Dec 13, 2017)

Hi all. Desperately need help as I emigrated to Cape Town with my TT and feel a bit on my own with a huge problem! 
It is the S line 2.0 Stronic with just 15,000 miles on clock. June 2012. Started misfiring and loss of power so stopped when safe, about 2 miles and had it towed to a garage I have used before. They did diagnostics and came up with misfire on cylinder 2. Fault codes PO300, PO302 P13OA. BTW this means nothing to me so write it all down! I authorised them to replace injector but then bad news. After replacing the fault codes went but still no power. Carried out basic compression test and found 1,3 and 4 were all fine.cylinder 2 only 1 bar pressure.
So they say only summary is that the faulty injector had already caused excess temperature within that chamber for a long time leading to a burnt valve or a piston ring collapsing or internal head damage at the valve seating area of the cylinder head above cylinder 2. They said this can only be diagnosed by removing it. This they reckon will be nearly a months work and as they go on a long holiday in this country for the rest of December and all of January it seems I won't have a car till March!
I would so appreciate any input or suggestions on way forward. I have no idea about cars and am dealing with this in a new country on my own. Just to know someone out there understands all this stuff would be good!


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## Hoggy (May 8, 2002)

Hi, They could use a snake eye camera in spark plug hole to inspect top of piston etc, but cylinder head will have to be removed eventually.
Hoggy.


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## brittan (May 18, 2007)

Some information on the fault codes below.

From what you say, the compression test is damning and the next logical step is to use a bore scope through the injector or plug hole or remove the cylinder head to see if the reason for the lack of compression lies with the vales or the piston. 
Piston problems may cause other issues with excess crankcase pressure. Has the oil dip stick popped out?

Does the long shut down apply to all, or most, garages? If so you may have to hire a car in the mean time.

*
16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected*
Possible Causes

Air Intake System leaking
Fuel Supply faulty
Injector(s) faulty
Ignition Cable(s) and/or Spark Plug(s) faulty
Ignition Coil(s) faulty
Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open
Camshaft Position Sensor (G40) faulty

Possible Solutions

Check Misfire Recognition
Check Air Intake System
Check Fuel Supply
Check Injector(s) and Injector Sealing
Check Ignition Cable(s) and Spark Plug(s)
Check Ignition Coil(s)
Check Exhaust Gas Recirculation (EGR) Valve (N18)
Check Camshaft Position Sensor (G40)

Special Notes

This DTC indicates that one or multiple cylinders are misfiring, but the ECU fails to identify the cylinder.

* 16686/P0302/000770 - Cylinder 2 Misfire Detected*
Possible Causes

Ignition system
Fuel injectors
Fuel pressure
Running out of fuel
EVAP canister purge valve
Evaporative emission system
Low compression
Base engine problems
Controle Module damaged

Special Notes

This feature search for engine misfire in a specific cylinder. Most of the time the cause for a misfire is a lack of combustion in a cylinder due to absence of spark, poor fuel metering, or poor compression.

*
P130A/04874 - Hide cylinder / Cylinder Disabling*
Possible Causes

Excessive Misfiring

Possible Solutions

Correct the root cause of the Excessive Misfiring

Special Notes

This DTC indicates that the Engine Control Module (ECM) has seen 'Excessive Misfiring' and the the ECM has switched 'OFF' fuel injector(s) to prevent engine and exhaust catalyst damage
To clear this fault code, it will be necessary to correct the root cause of the misfires and this code will then be able to be cleared.


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## Rosie SA (Dec 13, 2017)

Thanks for help so far. I really do t understand how a car with just 15,000 miles on clock can have such a huge problem


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## TT-driver (Sep 14, 2010)

In order to measure compression, they had to take the spark plugs out. Usually spark plugs tell a story. Either they are 'coffee with milk' brown (= OK) or black (not OK) or electrodes may have disappeared (not OK too hot)

A leaking injector can cause a hot spot causing the piston to melt. Then there is loss of compression. If the engine is turned in such a way that both valves on cylinder 2 are closed, pressurised air from a compressor fed into the cylinder through the opening of the spark plug would escape through the dipstick hole and the carter ventilation.

Another possibility is a broken valve spring. Then air may escape through the exhaust or the intake, depending on which valve spring is broken.

Sometimes valve springs can be replaced without removing the engine or its cylinder head. In all other cases I think the engine needs to be taken apart.


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## GaryG (Aug 21, 2016)

Rosie SA said:


> Thanks for help so far. I really don't understand how a car with just 15,000 miles on clock can have such a huge problem


To add to what the others have said, if this has to do with a faulty injector, the cause of the fault will be crucial - Audi might help with the costs. As far as becoming mobile again, the engine should not be run until the real cause is known and fixed.

Hope that it's a valve as it's the least worst fault.

Not a merry Christmas at all.


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## Sodde (Jun 1, 2015)

First a compression test to see which cylinder(s) is/are causing the problem and then they should do a cylinder leakage test to see where the compressed air they fill each cylinder with is escaping to. An experienced technician should have enough info at this point to know what's going on and if there's any doubt, you pull the cylinder head first. Pull the engine if you know the problem affects the bottom end but if you don't know...pull the head first.


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## Rob180bhp (Oct 8, 2017)

Sodde said:


> First a compression test to see which cylinder(s) is/are causing the problem and then they should do a cylinder leakage test to see where the compressed air they fill each cylinder with is escaping to. An experienced technician should have enough info at this point to know what's going on and if there's any doubt, you pull the cylinder head first. Pull the engine if you know the problem affects the bottom end but if you don't know...pull the head first.


This man talks sense

Sent from my SM-N950F using Tapatalk


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## Hoggy (May 8, 2002)

Rob180bhp said:


> Sodde said:
> 
> 
> > First a compression test to see which cylinder(s) is/are causing the problem and then they should do a cylinder leakage test to see where the compressed air they fill each cylinder with is escaping to. An experienced technician should have enough info at this point to know what's going on and if there's any doubt, you pull the cylinder head first. Pull the engine if you know the problem affects the bottom end but if you don't know...pull the head first.
> ...


Hi, OPs post stated No2 cyl compression was very poor, & all above had already been mentioned, so not a lot of sense required to repeat it. :? 
Hoggy.


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## Sodde (Jun 1, 2015)

Hoggy said:


> Rob180bhp said:
> 
> 
> > Sodde said:
> ...


From what I read, the fault codes were read and an injector was replaced to see if this would fix it....which it didn't. They then do a compression test and find out the compression is low on 1 cylinder. The OP stated that they then surmise that the injector has caused piston damage and requires engine removal; 1. without first doing a cylinder leakage test to see where the air is escaping from the cylinder and 2. without using a boroscope to confirm their theory.
The problem here is the issue is not being diagnosed correctly....and the OP needs to know that (he mentioned his lack of knowledge with vehicle mechanics). As I said, anyone who says they are a motor vehicle technician should know there are simple logical steps to evaluating a scenario like this...and its not happening at the place where it has the car. Just my 2 cents.
As stated in another post, diagnosis is key to making a full and correct repair. Fixing the damage is just part of it.


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