Spark plug gaps

[r5gtt]

That's good to know your cars running well now for whatever reason it is. Shane you don't know why it's messing around and misfiring at other times. 

[AJP]

That's good to know your cars running well now for whatever reason it is. Shane you don't know why it's messing around and misfiring at other times. 

Yeah I'm half hoping it plays up before or while it's plugged in tomorrow so we can at least get some idea of what's failing. Otherwise it's just a waiting game.

[r5gtt]

Pain in the butt fault finding for sure.  misfiring is usually easy to detect although with these bloody tfsi engines it can be a mystery as you're experiencing.

[pudding]

Keep checking for a persistent misfire in the fault codes.  Injector 3 went on mine.  Naturally no amount of plugs and coils thrown at it solved the problem!

I caught mine early though and was just a hiccup going into boost, not a full on stutter like yours does/did.  I replaced all 4 as I'm not going in there again!

It misfired at idle (intermittently) too, but it was a proper and continuous misfire, not a general lumpiness that these engines can sometimes have.

When it started misfiring at 2,500rpm, could you drive through it?  Or did pushing the pedal more not increase acceleration, or slow it down?  Just asking as I've seen that happen from a blocked cat before.  Can't remember what exhaust you've got on yours!

I could drive through the stutter on mine, so the injector was kind of working better with a higher duty cycle.  Just had a dead zone.

Keep digging, I'm sure the cause is there somewhere!

[AJP]

Keep checking for a persistent misfire in the fault codes.  Injector 3 went on mine.  Naturally no amount of plugs and coils thrown at it solved the problem!

I caught mine early though and was just a hiccup going into boost, not a full on stutter like yours does/did.  I replaced all 4 as I'm not going in there again!

It misfired at idle (intermittently) too, but it was a proper and continuous misfire, not a general lumpiness that these engines can sometimes have.

When it started misfiring at 2,500rpm, could you drive through it?  Or did pushing the pedal more not increase acceleration, or slow it down?  Just asking as I've seen that happen from a blocked cat before.  Can't remember what exhaust you've got on yours!

I could drive through the stutter on mine, so the injector was kind of working better with a higher duty cycle.  Just had a dead zone.

Keep digging, I'm sure the cause is there somewhere!

If I tried to drive through the misfire it'd just get worse, so I never attempted it and just backed off. The severity of it correlated with throttle - the more I dipped my toe in the heavier the misfires and the car slowed. It was a flurry of misfires (accompanied by 'pop pop pop' like a DSG burp) rather than one hiccup.

The exhaust is a full Powervalve with sport cat, new earlier this year. I did worry that the misfires wouldn't be doing the cat many favours!

I did have a misfire on idle a few weeks ago, this was fixed by replacing injector 4. There were no problems under load at this point.

[pudding]

Keep checking for a persistent misfire in the fault codes.  Injector 3 went on mine.  Naturally no amount of plugs and coils thrown at it solved the problem!

I caught mine early though and was just a hiccup going into boost, not a full on stutter like yours does/did.  I replaced all 4 as I'm not going in there again!

It misfired at idle (intermittently) too, but it was a proper and continuous misfire, not a general lumpiness that these engines can sometimes have.

When it started misfiring at 2,500rpm, could you drive through it?  Or did pushing the pedal more not increase acceleration, or slow it down?  Just asking as I've seen that happen from a blocked cat before.  Can't remember what exhaust you've got on yours!

I could drive through the stutter on mine, so the injector was kind of working better with a higher duty cycle.  Just had a dead zone.

Keep digging, I'm sure the cause is there somewhere!

If I tried to drive through the misfire it'd just get worse, so I never attempted it and just backed off. The severity of it correlated with throttle - the more I dipped my toe in the heavier the misfires and the car slowed. It was a flurry of misfires (accompanied by 'pop pop pop' like a DSG burp) rather than one hiccup.

The exhaust is a full Powervalve with sport cat, new earlier this year. I did worry that the misfires wouldn't be doing the cat many favours!

I did have a misfire on idle a few weeks ago, this was fixed by replacing injector 4. There were no problems under load at this point.

Sounds like it was/is going seriously lean in that case. I doubt a new aftermarket exhaust is plugged!

Any "System too lean" type fault codes? 

What about the swirl flaps, can they jam shut or something?  Not really sure how that works tbh, or when they switch on!

[Tfsi_Mike]

Pudding, what Lambda reading would be too lean?

2nd column is RPM Far right is Lambda

[AJP]

Got home about 15 mins ago. Gambled on the A614 and the ring road was indeed rammed.

Anyway. Big thanks to Tfsi_Mike for helping out with this. Proper gent. And the Cupra is a lovely in the flesh.

As predicted, no misfires, car performed very well. Let's see if some of you with more knowledge than me can spot anything!

[Tfsi_Mike]

Great to meet you Andrew.  Planned on taking the Cupra up the a52 so you could compare.  Traffic seemed to be building though.

Hope you get to the bottom if it, so frustrating.

Im going to see if I can graph som elf the date, just to make it a bit more visual.

[AJP]

Great to meet you Andrew.  Planned on taking the Cupra up the a52 so you could compare.  Traffic seemed to be building though.

Hope you get to the bottom if it, so frustrating.

Im going to see if I can graph som elf the date, just to make it a bit more visual.

I'll definitely come down again some time to go out in the Cupra mate, I'd like to know what all the fuss is about with the TTE! But yeah it's probably better when there's less traffic on the road. Hope you get some progress with the gearbox.

That'd be great if you could get some graphs up. I might learn a bit about logging too!

[Tfsi_Mike]

Just attempting one on Excel, Im a bit rusty.

[Dan_FR]

Post a link to logs (Dropbox etc) as some find it easier to work with the original CSV

[Tfsi_Mike]

Will do, if @AJP doesn't mind it shared.

[AJP]

Will do, if @AJP doesn't mind it shared.

Not at all

[Tfsi_Mike]