Misfire - not plugs or coil packs?!

[Lee M]

Hi all.

2.0 tfsi cupra:

I have a misfire on cylinder 2. Mainly on idle or low speeds and more noticeable after its warmed up.

I have replaced plugs this morning as I though it was that. My last set died at 15k and I've done about that since then. New plugs are up rated/colder iridium NGk as I'm running 2+.

Tried swapping coil packs between cylinders and that made no difference either, fault stays on cylinder 2.

Monitoring the misfire counter using VCDS it counts about 60-80 misfires in about 2 mins.

Am i looking at an injector fault as the next thing to look at? If so where are they located?

Cheers. Lee


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[towcester vag]

check fault codes?
also check the breather that is bolted to the front of the camcover as this are notorious for causing running issues

 

[Smee]

Is it always number 2? Even when you swap things around?

If so its got to be something in thst cylinder. Injector blocked? Faulty cable to coil?

What ever it is will need specialists help im sure

 

[Cupra R]

It is likely to be the injector at fault Lee I would of thought. I think the injectors are around the £90 mark. Bit of a pita to fit by all accounts.

 

[Nath.]

I didn't know that an injector could throw a spark plug missfire fault? If the injector fails to squirt fuel into the cylinder the coil pack will still fire the spark plug won't it?

 

[Cupra R]

It's a cylinder misfire. Not a specific spark misfire.

If there were no/little fuel in the cylinder the spark plug would still spark as you say, but the cylinder would still not fire correctly causing a misfire.

Getting 60-80 within a 2minute period is a lot.

 

[Bignod00]

My next thoughts would be an injector fault too! There was a Cupra in my local VAG Specialists the other day with these symptoms. An injector swap solved the problem. I paid attention obviously as anything tfsi is worth a look at!

Hope you get it sorted quickly mate!

 

[Cupra R]

My next thoughts would be an injector fault too! There was a Cupra in my local VAG Specialists the other day with these symptoms. An injector swap solved the problem. I paid attention obviously as anything tfsi is worth a look at!

Hope you get it sorted quickly mate!

Did you pay enough attention to find out how much it cost too mate ???

 

[tonto]

screwdriver, and an ear is all you need to diagnose an injector fault.

 

[Bignod00]

Did you pay enough attention to find out how much it cost too mate ???

Hahaha! I was getting taken out in an Aerial Atom so was a little too excited!

 

[Lee M]

I didn't know that an injector could throw a spark plug missfire fault? If the injector fails to squirt fuel into the cylinder the coil pack will still fire the spark plug won't it?

Hi mate,

No fault came up on vcds. I found it by monitoring the cylinder misfire counters on group 15 & 16 of the engine module. Only cylinder 2 gave a count all the other 3 stayed at 0.

 

[Lee M]

check fault codes?
also check the breather that is bolted to the front of the camcover as this are notorious for causing running issues

Ill have a look at it later today mate. Although its always cylinder 2.

No codes came up on vcds.

 

[Lee M]

Is it always number 2? Even when you swap things around?

If so its got to be something in thst cylinder. Injector blocked? Faulty cable to coil?

What ever it is will need specialists help im sure

Hi Mate,

Yes every time. New plugs in and still no.2. Then swapped coil packs 2 & 3 and then 1 & 3 and fault styled at cylinder 2.

 

[Lee M]

It's a cylinder misfire. Not a specific spark misfire.

If there were no/little fuel in the cylinder the spark plug would still spark as you say, but the cylinder would still not fire correctly causing a misfire.

Getting 60-80 within a 2minute period is a lot.

You can watch it count up to be honest. It's irratic and can reset the counter sometime (happens after a static period of ~ 10 sec) and then counts again.

 

[Lee M]

My next thoughts would be an injector fault too! There was a Cupra in my local VAG Specialists the other day with these symptoms. An injector swap solved the problem. I paid attention obviously as anything tfsi is worth a look at!

Hope you get it sorted quickly mate!

Cheers mat

I'll be an expert in intake manifold removal after this fix!

 

[Lee M]

screwdriver, and an ear is all you need to diagnose an injector fault.

I couldn't see the injector to get the driver on it mate.

 

[Cupra R]

Hahaha! I was getting taken out in an Aerial Atom so was a little too excited!

In that case, I'll let you off

 

[Cupra R]

Are you gonna DIY it Lee or take it somewhere?

You don't want that cylinder to be running lean if it is malfunctioning.

 

[Lee M]

Was going to DIY? What the consequence It the running lean? Excuse my lack of knowledge?

It needs a new clutch and fly vsoon so I could get AMD to do it?

It's been like it a little while when idling. But it doesn't notice when being driven.


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[Cupra R]

Was going to DIY? What the consequence It the running lean? Excuse my lack of knowledge?

It needs a new clutch and fly vsoon so I could get AMD to do it?

It's been like it a little while when idling. But it doesn't notice when being driven.


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Lean can result in piston damage.

So, it's not noticeable when under power only idling?