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Discussion Starter · #1 ·
Hi

I have a 2013 T5.1 2.0 180hp 4motion.
While driving a few weeks ago, the engine just stopped.
Som troubleshooting revealed that the lift pump in the tank had stopped working.
I got the tank out, replaced it,
and primed the pump until I had diesel flowing nicely from the return line of the fuel rail.

But the engine still would not start.
Im a novice in vcds, but manage to do some diagnostics,
and there is no feedback from the cam position sensor while cranking.

So I took of the timing belt cover, and verified that the belt had not snapped.
Im thinking that the cam sensor itself might need replacing, but can't seem to find where it is located
on this engine.
Could anyone point me in the right direction here?
 

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Discussion Starter · #2 ·
A small update on this; I managed to locate the sensor.
It is positioned close to the camshaft gear, and the cable is routed behind
the timing belt. So the timing belt has to come of in order to change it.

I also ordered the water pump and timing belt kit,
as it makes sense to change these since the belt has to be removed anyway.
 

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Be interested to see how you get on. Normally if the cam sensor fails the engine will still run using info from the crank sensor. Bad starting is usually the result, never heard of a cam sensor actually cause the engine to stop. Although if the crank sensor fails that will do it.

Did you find the cam signal in group 051, second figure in from the left? Don't know if it is the same on the 2.0 engines.

051,2,Camshaft Speed,(G40),Specification: Half Engine Speed ±50 RPM/min
 

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Discussion Starter · #5 ·
Be interested to see how you get on. Normally if the cam sensor fails the engine will still run using info from the crank sensor. Bad starting is usually the result, never heard of a cam sensor actually cause the engine to stop. Although if the crank sensor fails that will do it.

Did you find the cam signal in group 051, second figure in from the left? Don't know if it is the same on the 2.0 engines.

051,2,Camshaft Speed,(G40),Specification: Half Engine Speed ±50 RPM/min
Yes, I would also asume that the engine would keep running with input from the crank sensor.
Started on timing belt change today. After taking of the aux belt, I started turning the crank in order to lock everything down.
I felt the crank slip like it was jumping a tooth. Took of the pulley and made a less than good discovery:

Wheel Tire Automotive tire Motor vehicle Vehicle brake


Im asuming this happened when the engine initially failed.
I have not checked if the waterpump has seized yet.

Not sure if I should try to put on the new belt and waterpump
and hope that by som miracle the valvetrain is not crushed.

Or just start to disassemble the top.
 

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It's always worth a try. The odds aren't good but it's worth a go since you have gone that far. Personally I'd just stick the belt on it you just want to know if valve damage is done.

You can attempt a start without putting most things back on as long as you can turn the engine two complete revolutions slowly by hand with a spanner. Put the crank pulley back on (without the cam covers. No need to fit the alternator belt or even the engine mounting if the engine is supported with a jack or a support beam. Don't forget to replace any vacuum pipes, earths or other vital wiring and tie up anything could be fouled by the turning pulleys. Good luck! Unfortunately you will probably need it. :(
 

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Discussion Starter · #7 ·
It's always worth a try. The odds aren't good but it's worth a go since you have gone that far. Personally I'd just stick the belt on it you just want to know if valve damage is done.

You can attempt a start without putting most things back on as long as you can turn the engine two complete revolutions slowly by hand with a spanner. Put the crank pulley back on (without the cam covers. No need to fit the alternator belt or even the engine mounting if the engine is supported with a jack or a support beam. Don't forget to replace any vacuum pipes, earths or other vital wiring and tie up anything could be fouled by the turning pulleys. Good luck! Unfortunately you will probably need it. :(
Thanks for the advice. I will attempt to do this
 

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Discussion Starter · #9 ·
Thanks for the input. I took your advice yesterday and continued with the timing belt and water pump replacement.
Found the lock positions for the camshaft, crankshaft and diesel pump.
got everything timed, and manualy rotated it 3 rounds.
Felt fine, and there was compresion. Everything still lined up, and locking tools slid into place.

Then attempted to start it. Cranking sounds normal, and it also sounds like it is close to firing.
Did many attempts, and a few times, theres 1 or 2 ignitions. But it sounds like they fire too early.

Alsto tried starting gas, but I find this difficult to balance on diesels. As it either dont fire, or fire way to early halting the engine.

Tid a new test today, with vcds connected:

Rectangle Azure Font Screenshot Software


Since I am new to taking measurements live, I just ticked a few boxes that seemed relevant.
If i understand correctly, fuel pressure is good, and Im happy to see feedback from the camshaft sensor.

Not sure how to go from here. If my cam lifters are crushed, that may very well be my starting problem right now.
But hoping theres some more tests i can do, before going to the step of opening the cylinder head.
 

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I think you will have to take the rocker cover off for a look. Whenever I've seen crushed lifters they have gone along with bent valves because the oil in them can't escape quickly enough for them to collapse in time to save the valve. The 2.0 might be different but I have no experience with them.

I have a feeling that if there actually has been piston to valve contact (and unfortunately that is most likely) some valves will be bent so you will end up taking the head off. It's always worth a try because it's a lot of work for nothing if not. I don't know of any certain test you can do without dismantling. Does the engine feel like it has 4 clear compressions and you turn it with a spanner? A bent valve normally means virtually no compression on that cylinder and you can clearly feel it as the engine is too easy to turn on that cylinder. You can usually hear it too on cranking with the starter as the engine cranking speeds up momentarily.
 

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Discussion Starter · #11 ·
I think you will have to take the rocker cover off for a look. Whenever I've seen crushed lifters they have gone along with bent valves because the oil in them can't escape quickly enough for them to collapse in time to save the valve. The 2.0 might be different but I have no experience with them.

I have a feeling that if there actually has been piston to valve contact (and unfortunately that is most likely) some valves will be bent so you will end up taking the head off. It's always worth a try because it's a lot of work for nothing if not. I don't know of any certain test you can do without dismantling. Does the engine feel like it has 4 clear compressions and you turn it with a spanner? A bent valve normally means virtually no compression on that cylinder and you can clearly feel it as the engine is too easy to turn on that cylinder. You can usually hear it too on cranking with the starter as the engine cranking speeds up momentarily.
I did not count compressions when turning manualy. Cranking seems very uniform.
Might try again with some starting gas, before taking the rocker of.
Im hoping for the longest to avoid taking of the cylinder head,
while knowing it might be the only way to solve this.

Im learning some new skills with this problem though.
Timing belt change was outside my comfort sone before.
But getting that done was very satisfying, despite the additional engine problems.
 

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I think you will have to take the rocker cover off for a look. Whenever I've seen crushed lifters they have gone along with bent valves because the oil in them can't escape quickly enough for them to collapse in time to save the valve. The 2.0 might be different but I have no experience with them.
Yes, the CR engine is a lot different to the PD (which has bucket tappets, and normally a bucket tappet will nearly always bend a valve if the cam timing goes out.)
The CR has roller rockers, linking hydraulic compensators to the cam lobes and valves. In the middle of the rockers are needle bearing rollers, which run on the cam lobes, eliminating cam lobe wear, and reducing friction for more efficiency. If a piston hits a valve, these rockers normally snap in half where the bearing rivet goes.
I assume this is a designed weak spot, as I've come across this engine, and several similar VAG engines, and all have broken the rockers, not bent the valves.
 

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Discussion Starter · #13 ·
Yes, the CR engine is a lot different to the PD (which has bucket tappets, and normally a bucket tappet will nearly always bend a valve if the cam timing goes out.)
The CR has roller rockers, linking hydraulic compensators to the cam lobes and valves. In the middle of the rockers are needle bearing rollers, which run on the cam lobes, eliminating cam lobe wear, and reducing friction for more efficiency. If a piston hits a valve, these rockers normally snap in half where the bearing rivet goes.
I assume this is a designed weak spot, as I've come across this engine, and several similar VAG engines, and all have broken the rockers, not bent the valves.
I used to have a Audi V6 2.5 tdi (The one that ate camshafts),
where those rockers broke and fell of. Cant remember if it had roller rockers.
Had camshafts, rockers and lifters replaced and it worked fine for the duration of my ownership.
 

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I used to have a Audi V6 2.5 tdi (The one that ate camshafts),
where those rockers broke and fell of. Cant remember if it had roller rockers.
Had camshafts, rockers and lifters replaced and it worked fine for the duration of my ownership.
The AKE earlier Audi engine had sliding surface rockers, and these wore out, and either half fell out and shattered, or just fell out intact and that valve stopped working. The later BAU engine had hollow steel camshafts with the lobes pressed on. The rockers were now roller rockers, so wear was eliminated, but in rare instances, the lobes slipped on the camshaft causing pistons to hit valves, and the rocker to break. Not seen any of these Audi engines with bent valves, and normally you wouldn't know of any broken rockers until 2 of the same valves had them broken in the same cylinder, and a mis fire would start, then you would find 3, 4 or even 5 broken or fallen out.
 
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