Tiguan 2012 manual TSI occasional misfire

[TMac]

Hi VW mind trust,
I have been told a "I don't know" by my mechanic and so I thought I would ask the VW team to see what you think...

The current problem is intermittent and seems to be a misfire on cylinder 2. About 11k ago there was a similar problem and the spark plugs were changed and ignition coil replaced for cylinder 2. Problem seemed to be solved.

On Sunday a week ago my Tig suddenly was running rough with the engine light coming on - misfire felt like it was back. The engine light was on and blinked once about 2 times, and EPC came on for a bit, no smoke visible, but power dropped like last time so was 99% sure misfire. About 10km after coming on the rough running seemed to stop (was limping home). When I drove to the mechanic on Monday morning the problem seemed to have gone. Conveniently whilst at the mechanic the problem reappeared and they got a similar misfire on cylinder 2 again. Apparently the spark plug came out a bit wet. The problem seems to have gone, but I think it might come back. Mechanic said they are unsure of the problem.

I will get some history of what has been fixed in the car over the journey but I am pretty sure the fuel pump was done about 170k.

Let me know what you think might be a cause of the problem. Any suggested VW mechanics in the Manly area? Is getting a carbon clean (walnut blast) something worth considering?

Here is a bit more about the car (not sure if useful or if more info is required just ask and I will add).

Tiguan 2012 132kW 6sp manual.
I have owned since about 50k and now up to 211k km - bought in late 2017.
Tend to drive a fair bit for work so up to 1000km a week with most being on the freeway up to Newcastle.
Tends to use a bit of oil, which seems to be common, and I think about 1L about every 2000km.
Doesn't blow smoke and fuel consumption is very consistent (680-740km per tank). Have been using E10 usually, although mechanic suggested using 98 more often (tend to put a tank through occasionally prior to this).
Have noticed a zzzzzz / clicking noise when off the coming off power and idling with gears engaged (to try to describe the sounds as when not pedaling a push bike the clicking noise you get from the rear cluster sounds no dissimilar - since only when no power I was assuming this is a normal sound).
The engine light has occasionally come one over the last 100kM. I have usually assumed this was due to the emissions being out of spec due to the fuel and haven't worried too much. Has nearly always gone away on the next fuel tank fill. Occasionally have had a bit of a drop in power, but as hasn't lasted I have assumed injector, or similar, briefly blocked and problem gone.
I am wondering if any of the above is related and thus have put it down if this helps.

Been getting the car serviced a Balgowlah Automotive (Sydney) regularly which I think have been good and are close to home.
Car is in pretty good knick for the age and I like the manual so at this point (and with high costs for used cars at the moment) am keen to keep it (go for 300k km?) but don't want it to become unreliable or a money pit.

[MIG]

If the plug is wet, that means it's getting fuel. That leaves only two things it could be still air and spark.
Carbon build-up would have a more consistent misfire, eg always when cold or under load, and would not disappear at times.

If I were to just guess, I would say another coil pack went, or the replaced one failed again (Was an OEM one used when replaced 11k ago?)

[TMac]

Thanks MIG.
Gremilins are back at the moment. I am 95% sure replaced coil was OEM. I do have another I was thinking to try.

[Lucas_R]

I would replace all 4 coil packs. Replacing just 1 is always dangerous as the others are usually not far behind in terms of being ready to fail.

[TMac]

So off to the mechanic and diagnosis was too much oil into cylinder 2 has meant spark plug was gunged up. New spark plug and all good.

However...oil in means likely the valve seals or cylinder gasket (?) is needing to be replaced at some stage in the near future. And mechanic thought the "zzzzzz" noise with power off could be a sign the timing chain tensioners are a bit slack.

Seems the 3 options to fix are:
- engine rebuild to repair seals - but old car (215k km) so other things are also old
- second hand engine - got to find one not too old and my car is old so other things are likely to keep repair bills coming through
- change car

What do you reckon? How much would options 1 or 2 be roughly?

[h100vw]

I would not be putting anything but 98 in it. And definitely not E10.

An expensive fix for all 3 options.
Just doing a tensioner and chain is over a grand.
Engine swap little change from 6k. Depends on the engine cost. Any engine would want the chain replacing as insurance.

[VWpierre]

I have the identical symptoms, running on 3cyl, replaced plug, was then ok for a week, then went again, another plug fouled. I swapped coil packs to prove coil packs were ok. Did engine oil flush, also petrol injecter cleaner (good to do). Then happened again! For investigation, I pulled the PCV/ oil control...
...and found the hose going to intake FULL of OIL! Easy fix!
Genuine cost of this item=$299, OEM =$37! from Ebay in AU. I saw recommendation to replace this every 20Klm or so.
Do a search on: 06H103495


BTW: On Youtube shows check camchain on your iphone!

[VWpierre]

Update...Further down the track, the PCV replacement did not fix, problem still occurring i.e. despite replacing new plugs, new coilpacks and then all injectors.
Tig runs beautifully-smoothly otherwise, starts easily, no smoke, good compression, occasionally fouls #2 plug. (wet with fuel) Pulling the plug and cleaning it resolves the issue immediately. Fouling seems to occur on idling, eg stuck in traffic. Racing the engine wont clear it, I putt home on 3 cylinders.
If i park the Tig, and don't drive it for 3days, fault magicly gone! Seems to prove it was fuel stopping plug firing. Only codes showing up is misfire cyl#2.
So what is the cause? Intermittent spark drive from ECU? ECU>injector power fault? CAM chain? (180Klms) sensors?

[jewfish1010]

Not sure if you still own the car, but I recently bought a 2012 Tiguan TSI (198,000km) for my daughter, which started misfiring within minutes of purchasing (privately).

Pulled the plugs and discovered cylinder 2 had a fouled plug. Cleaned the plug and it ran fine again. This went on for a number of weeks, during that time I replaced the PCV but the problem persisted after I handed it to my daughter.

My daughter was driving it a fair bit and it would go to the low oil level every ~500km or so - requiring 1L to top up.

I did a bit of research into the issue and found it's fairly common for these (VW/Audi) engines to burn oil.
The consensus is that they use low tension piston rings which causes the oil control ring to clog up with carbon, causing oil to get past the rings and into the combustion chamber.

Some engines get so bad that the oil fouls the spark plugs - causing a misfire or complete shutdown of the cylinder.

On this particular car, I observed misfiring occurring after driving down a long hill, where engine braking was occurring (an off-throttle condition) - meaning the ecu did not command fuel/spark during this time - allowing oil to accumulate on the plug.

Given the issue was limited to one cylinder, that meant it had to be rings or valve stem seals. My first thought was valve stem seals as there was some smoke on startup in the morning. But after speaking to a vw mechanic, he said he rarely replaces these, so I was more inclined to think the problem was piston rings.

The typical fix is to replace the pistons and rings ($$$).

During my research I found this video on youtube: https://www.youtube.com/watch?v=V5e3xQeXCLo
where the guy has all the symptoms I was dealing with. Being somewhat mechanically inclined, I gave it a go.

Got my hands on a can of Berryman's B12 and performed a piston soak. Given that B12 is expensive and hard to get in Australia, I used about half the can on cylinder 2 which was obviously the worst.

Since performing the procedure, the oil level hasn't dropped in ~700km (would normally be past the low mark) and no misfiring as yet.

[Lucas_R]

Ive seen some of those piston soak videos, and have mentioned it to my manager who has a 2.0TSI engine in his Audi A4 and it drinks oil like no tomorrow. Dissolving the carbon from the piston rings seems to be a relatively cheap and easy way to recify the issue. Even if you have to do the piston soak every 2-3 years, its still going to be cheaper than buying all the oil @ $20 per litre.

Good to hear someone locally has done it and had success - all the videos and info I have seen are from America.

The Berrymans B12 product is about $35 for a 444ml bottle, so its not cheap to buy here in Australia - but its heavily marked up because its a low volume product for Australia plus you are paying the freight cost to bring it in from USA. In the USA its about $5 a bottle. Im sure a carby cleaner product would do the same job, and much cheaper at about $50 for 5L.

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