vw scirocco 2.0tsi missfire help

[Wheatley173]

Hi,

I have recently purchased a scirocco 2.0 tsi with and have recently found the car to be having issues with misfiring. This is really noticable when accelerating under load.

I have dropped it off at a German car specialist who I have used several times for my other cars to diagnose. I was expecting something like coil issues or similar.

The diagnostic has shown misfire on cylinder 3 and also maf sensor. I believed the code from the Maff sensor would be due to my friend who has a mechanics head on him pulled the connector to see if it made any difference, which it did not
They has ran over an hours diagnostic and the mechanic who has checked all areas has recommended using a fuel cleaner to help the issue and then to monitor.

This seems like a bit of an easy fix to me and my friend also agrees it seems a bit simple.

I would be totally overt he moon if this simple issue resolved this, but I just have a gut feeling it will not. I was expecting at least coil changes, plugs and maff sensors, so to be told a bottle of fuel cleaner could be the answer seems a bit nice. If the fuel cleaner doesn't solve it, it's going to be removing the head for further investigation.

Can some one prove me wrong, would love to hear from any one whose had a similar experience to me on this and has actually seen fuel cleaner work. I've always had my doubts about it, but then again I've never used it.

Any one with knowledge on the 2.0 tsi with thoughts on symptoms like this.

Thanks

[Wheatley173]

No, I didn't intend to jump to removing the head, what I mean is that I already expect that the diagnostic that has been happening today has already checked coil, plugs and Matt

This is why I am surprised to see he only recommend the fuel cleaner . I was certain he was going to say one of the above and can only imagine the head removal if the fuel cleaner doesn't work as all other checked.

[Wheatley173]

I was starting to think injector if all other areas had been covered off as being ok. I woukd imagine that he feels the injector is dirty and would require being cleaner through the additive, but I would second guess then if that doesn't work it would be replacement.

Any ideas of cost to replace an injector ?

[Wheatley173]

Well it's apparently ready for me to collect, so we will see how it goes. But I doubt it will last. Maybe I shouldn't be so negative.

Doesn't sound like it can be anything else other then injector if all others have been checked, so at least I have an idea of where I will be standing if it happens again

When I pick it up I'll find out what has actually been checked over as I would imagine plugs, coil and maff had been checked in order for them to come to the conclusion that none of these need replacing

[Wheatley173]

datum77 said:

If any car has a periodic misfire, it is 99% certain that it is NOTHING to do with the head/valves/pistons etc. Any fault in this area will be permanent and not just on Thursday's if Eastenders is on. (Damage to pistons or valves cannot mend themselves).
Your problem sounds electrical, and slightly less likely, fuel. This includes the injectors. Renewing components is a method of last resort, but can cure the fault, even if the diagnostic equipment fails to point to anything in particular. After all, that expensive computer equipment is only as good as the guy that's using it.

Keep well away from Kwok Fut.

I've just picked it up. There is definitely an improvement, but I'm certain it's not 100% right. Which lead to believe that surely they have had to mess about with coil and spark plug for number 3 and putting it back together has some how improved it some what, but not cured it. I'm starting to think it would be worth replacing the coil and plug in number 3 just see what difference it would make

So based on what your saying you think something electrical being plug, coil or injector then ?

[Wheatley173]

So I've been out for a longer drive and the probkem is still very much there.

I'm sure it gets worse as the engine gets hotter.

My mate seems to think it is the coil if it's heat sensitive

Any one have any thoughts ?

[Wheatley173]

Faxo said:

If it's cylinder 3, swap coils 3 & 4 round. If its still cyl 3, swap plugs round. If it's still cyl 3, either replace injector, or swap injectors round. If it's still cyl 3, you've a wiring or compression problem!

I've done injectors on these engines, they dribble. A few have dribble so much, they've slightly bent a rod. Didn't know until started burning oil, when head was removed you could see a blue line down the bore due to heat

Thanks for the advice, you sound knowledgable on this engine. Do you think though the fact that the symptoms get worse as the engine gets warmer points to a dodgy coil?

I feel like taking the car back tomorrow morning and insisting they fit a new coil to try it

[Wheatley173]

The car is much worse under load say for instance, low rpm in 5th gear, foot to the floor and then it struggles. If I drop it to 3rd it feels much happier although the signs are still there.

So as you say driving up a hill in a hoggish gear, the car would really struggle on this

[Wheatley173]

Also I would say the misfire is always present. Not really noticeable when cold but once heated up its definitely more noticeable even at idle

[Wheatley173]

So this morning the car drive so much better being that engine is cold from standing over night, but still not right. Driving back to the garage, when driving over a canal bridge at about 30mph in 4th I notice the hesitation again.

I have taken it back and explained the symptoms get much worse as the engine gets hotter.

I have asked them to change all spark plugs as not sure how old they are and also the coil on cylinder 3.

Fingers crossed

The fact the symptoms gets worse when hot makes me feel that it's the coil.

Peoples thoughts on this

[Wheatley173]

So I thought I would update on this.

I've picked the car up after having 4 new plugs and 4 new coils fitted and I'm pleased to say all seems well

I've taken it down some country lanes and made sure it got really hot and I'm pleased with the outcome. Drives so much differently.

Thanks for every ones help

[Wheatley173]

Hi,

I started this thread a long time ago. My issue was down to coil pack. Probably worth changing, if no joy from the plugs. Good luck with getting it sorted.