Hello from Czech Republic, I am here with a problem with 1.8 TSI CDAA engine. Car is 2011 Seat Leon FR, but it's not important, engine is the same in many other models.

 

Here is my story with this engine.

I bought the car last year in Germany with some light knocking coming from the engine. We brought it home and immediately started investigating what is the problem.

After removing head, we found it. Cyl 3 was weirdly melted. Wrong coil, plug or injector? Who know... Cylinder wall was okay, some light scratches but you can't feel them with nail.

I bought ONE new piston in STD size (measured bore/old piston, STD is correct size) and installed it. I also installed new timing chains, guides, tensioners, NGK coils and plugs, injectors cleaned and tested with no problems (that's weird, because we thought injector 3 will be faulty, but it was okay...). When assembling head I found that variable timing gear on intake cam has some play. I discussed it with some friends who had hands on cams from TSI engines and they never had a play in it, so I bought new OE camshaft. New cam had obviously no play in gear, so after that I assembled it. Car started fine, runs very well.

 

After a few months of driving, I found another problem. Oil consumption. 2 - 2.5L/1000km. So I started to buying parts for rebuild. New pistons, gaskets, PCV valve, another new plugs etc. Basically everything you need.

One day I started to disassembling the engine and pulling pinston nr. 1, 2 and 4. 3rd pistons was okay, since was replaced with revised one and Cyl 3 has no problem with oil consumption (spark plug was brown, no signs of consuming oil).

With new pistons I also installed new valve stem seals and cleaned all valves (intake had some carbon build up).

Assembled the engine, started it, runs very well until first drive...

 

And here it beginning.

 

All 4 cylinders randomly misfiring. But only between ~1000 to 2500 rpms. No matter if it's cold or hot. After passing 2.5k rpms, misfiring is gone and engine pull hard to revlimiter with zero misfire (logged with Delphi diagnostic).

So, I bought another pile of parts and started replacing. New OE plugs and coils, Facet cam and crank position sensor, Delphi knock sensor, INA timing control valve (it's bolted inside intake cam) and INA control solenoid. No change. It was pointless to replacing all these parts, but car is not throwing any codes and I was out of ideas.

After that I also checked timing. Removed all chains and guides and set it again. No change. Timing was okay of course.

 

I have no idea what is that. So that why I am here. Is here someone with some ideas what could be wrong or what I should check next?

Also sorry if I made some mistakes in text. I learned English 10 years back.

 

 

Thanks for help!

Could it be fuel related is the fuel pressure OK across the rev range? I'm no expert but if across all four cylinders it must be something common to all four.

Check amperage at low pressure pump as well as checking pressure before and after HPP. Intermittent fault i the LPP could cause these symptoms depending on how the behave exactly.

On 13/08/2019 at 14:20, MirekEhrlich said:

Hello from Czech Republic, I am here with a problem with 1.8 TSI CDAA engine. Car is 2011 Seat Leon FR, but it's not important, engine is the same in many other models.

 

Here is my story with this engine.

I bought the car last year in Germany with some light knocking coming from the engine. We brought it home and immediately started investigating what is the problem.

After removing head, we found it. Cyl 3 was weirdly melted. Wrong coil, plug or injector? Who know... Cylinder wall was okay, some light scratches but you can't feel them with nail.

I bought ONE new piston in STD size (measured bore/old piston, STD is correct size) and installed it. I also installed new timing chains, guides, tensioners, NGK coils and plugs, injectors cleaned and tested with no problems (that's weird, because we thought injector 3 will be faulty, but it was okay...). When assembling head I found that variable timing gear on intake cam has some play. I discussed it with some friends who had hands on cams from TSI engines and they never had a play in it, so I bought new OE camshaft. New cam had obviously no play in gear, so after that I assembled it. Car started fine, runs very well.

 

After a few months of driving, I found another problem. Oil consumption. 2 - 2.5L/1000km. So I started to buying parts for rebuild. New pistons, gaskets, PCV valve, another new plugs etc. Basically everything you need.

One day I started to disassembling the engine and pulling pinston nr. 1, 2 and 4. 3rd pistons was okay, since was replaced with revised one and Cyl 3 has no problem with oil consumption (spark plug was brown, no signs of consuming oil).

With new pistons I also installed new valve stem seals and cleaned all valves (intake had some carbon build up).

Assembled the engine, started it, runs very well until first drive...

 

And here it beginning.

 

All 4 cylinders randomly misfiring. But only between ~1000 to 2500 rpms. No matter if it's cold or hot. After passing 2.5k rpms, misfiring is gone and engine pull hard to revlimiter with zero misfire (logged with Delphi diagnostic).

So, I bought another pile of parts and started replacing. New OE plugs and coils, Facet cam and crank position sensor, Delphi knock sensor, INA timing control valve (it's bolted inside intake cam) and INA control solenoid. No change. It was pointless to replacing all these parts, but car is not throwing any codes and I was out of ideas.

After that I also checked timing. Removed all chains and guides and set it again. No change. Timing was okay of course.

 

I have no idea what is that. So that why I am here. Is here someone with some ideas what could be wrong or what I should check next?

Also sorry if I made some mistakes in text. I learned English 10 years back.

 

 

Thanks for help!

Did you solve the problem?

Yes and no. Noone can solve the problem, so I started to investigate it by myself.

Found that when I disconnected intake cam variable timing solenoid, all problems with misfires went away. I had no idea why, so I puulled intake camshaft, replaced it agai  with new OE unit also with OE variable timing parts.

No change.

But engine misfires only when variable timing is active.

So I had no idea what to do with it. Driving with disconnected solenoid throw codes and engine is lazy in low rpms.

But then I talked with guy who doing chip tuning. I got car remmaped with variable timing turned off in ECU. Engine has more power and no variable timing is not noticeable at low rews anymore.

Problem is stilm there, but I don't know how to solve it correctly. I dumped a big load of money in this thing and I really don't want to continue.

I have ~8k kms on the engine after remap without any issues at all. So I leave it like this.

21 hours ago, MirekEhrlich said:

Yes and no. Noone can solve the problem, so I started to investigate it by myself.

Found that when I disconnected intake cam variable timing solenoid, all problems with misfires went away. I had no idea why, so I puulled intake camshaft, replaced it agai  with new OE unit also with OE variable timing parts.

No change.

But engine misfires only when variable timing is active.

So I had no idea what to do with it. Driving with disconnected solenoid throw codes and engine is lazy in low rpms.

But then I talked with guy who doing chip tuning. I got car remmaped with variable timing turned off in ECU. Engine has more power and no variable timing is not noticeable at low rews anymore.

Problem is stilm there, but I don't know how to solve it correctly. I dumped a big load of money in this thing and I really don't want to continue.

I have ~8k kms on the engine after remap without any issues at all. So I leave it like this.

Thanks man ! This solved my problem also. I am going to replace the vvt solenoid and see if that improves it. Thanks a lot been worrying a long time. 

On 21/02/2020 at 20:12, MirekEhrlich said:

Yes and no. Noone can solve the problem, so I started to investigate it by myself.

Found that when I disconnected intake cam variable timing solenoid, all problems with misfires went away. I had no idea why, so I puulled intake camshaft, replaced it agai  with new OE unit also with OE variable timing parts.

No change.

But engine misfires only when variable timing is active.

So I had no idea what to do with it. Driving with disconnected solenoid throw codes and engine is lazy in low rpms.

But then I talked with guy who doing chip tuning. I got car remmaped with variable timing turned off in ECU. Engine has more power and no variable timing is not noticeable at low rews anymore.

Problem is stilm there, but I don't know how to solve it correctly. I dumped a big load of money in this thing and I really don't want to continue.

I have ~8k kms on the engine after remap without any issues at all. So I leave it like this.

Hey man did you tried to replace the camshaft adjuster magnet ? This part right here

I mean did you try it after replacing the camshaft adjuster magnet ?

Of course I tried, I even bought new OE parts, not reproduction. Still no luck.

We also tried to replacing ECUs, flashing them etc. There is someting screwed up, but noone can find the problem and solve it.

As I wrote, car is running well after remap, so I am not trying to solve this problem anymore.

On 23/02/2020 at 17:03, MirekEhrlich said:

Of course I tried, I even bought new OE parts, not reproduction. Still no luck.

We also tried to replacing ECUs, flashing them etc. There is someting screwed up, but noone can find the problem and solve it.

As I wrote, car is running well after remap, so I am not trying to solve this problem anymore.

Hey man. Sorry i am bothering you this much, but i am myself trying to figure out the problem. Did you change the camshaft control valve. This lil thing in the picture ?

Tried, no luck. 🙂

9 minutes ago, MirekEhrlich said:

Tried, no luck. 🙂

What about the cam bridge ? If the screen on this this goes, its unable to supply enough oil to the camshafts. This part in the picture

This is a typical topic about what NOT to do when repairing an engine. Throwing parts blindly, without any evidence of faulty parts. I reckon the parts cost in total more than a new engine.

That engine had a catastrophic failure in the past. There are still mechanical issues. I would have tested it mechanically very thorough before even buying it.

5 minutes ago, RicardoM said:

This is a typical topic about what NOT to do when repairing an engine. Throwing parts blindly, without any evidence of faulty parts. I reckon the parts cost in total more than a new engine.

That engine had a catastrophic failure in the past. There are still mechanical issues. I would have tested it mechanically very thorough before even buying it.

How would one find out the problem then ? If our way is wrong, please tell me your way of diagnosis. What would you do..?

Well, the engine is not mechanically damaged. Since it's remaped with cam timing turned off, the engine survived a lot of abuse without any problems. A few weeks back I checked cylinder pressure and all 4 cyls have the same number with a few psi difference. No oil or water consumption, clean oil and no metal flakes in oil filter.

Misfiring on all 4 cylinders is not a mechanical problem. It does not make any sense how some mechanical part can cause this problem. There is probably some gremlins in electrical system, but as I said, I am done with this car and besides regular maintanance, I am not going to dump any more money in trying to solve it.

Car runs very well with remap, so I have no reason to trying.

3 hours ago, MirekEhrlich said:

Car runs very well with remap, so I have no reason to trying.

I would say the remap hides / minimizes deeper faults.

3 hours ago, MirekEhrlich said:

A few weeks back I checked cylinder pressure and all 4 cyls have the same number with a few psi difference.

If you're talking just about compression check, that is not enough. A leak down test is more precise and reveals hidden issues.

4 hours ago, Ayush said:

How would one find out the problem then ? If our way is wrong, please tell me your way of diagnosis. What would you do..?

I would had checked the cylinder bores for deformations, also connecting rods and bearings. Let's not forget that most often a piston meltdown happens when severe detonation occurs. No wonder the engine was sold (probably cheap)...

 

PS. Mirek, we got it, you are not willing to do any more diagnose or repairs.

We are discussing for other members that are interested to learn from your mistakes.

4 hours ago, MirekEhrlich said:

Well, the engine is not mechanically damaged. Since it's remaped with cam timing turned off, the engine survived a lot of abuse without any problems. A few weeks back I checked cylinder pressure and all 4 cyls have the same number with a few psi difference. No oil or water consumption, clean oil and no metal flakes in oil filter.

Misfiring on all 4 cylinders is not a mechanical problem. It does not make any sense how some mechanical part can cause this problem. There is probably some gremlins in electrical system, but as I said, I am done with this car and besides regular maintanance, I am not going to dump any more money in trying to solve it.

Car runs very well with remap, so I have no reason to trying.

Hey man you didn’t answer my question did you try changing this part ? 

Quote

 

hi guys, 

same thing is happening to my car - Octavia MK2 2021, CDAA 1.8 TSI 118 Kw. 

Misfire on random cylinder and limp mode - random cylinder disabled. 

Only errors shown in diagnostics are p0300 and then p030x depending on which cylinder misfire occurs. 

Car is 3000 km after rebuild - new pistons, timing chain, PCV, fuel injectors, Timing Camshaft Control Valve Solenoid.

what was checked:

-fuel pressure checked - ok,

-no air leak

-PCV

-eletric wiring - connectors and pins

 

Any ideas what might cause the issue? 

 help much appreciated. 

thanks. 

Is the Fuel ok, had a couple of cars recently with water in fuel. Both had random multiple misfires

will check, thanks  

20 hours ago, IKQ said:

 

so it's not fuel :/.

Any idea what else to check? 

thanks.

So in my case it was faulty pin in ECU connector.