2.0 TFSi Misfire probs

[Jedimaster65]

Hi Guys,
I am new to the site and am finding it brilliant !
I have a serious misfire on my Leon TFSi Sport (18 months old).
I had an APR remap after 4 months (producing 260 BHP approx) and it has been fantastic for 12 months.
Now I have had a series of severe misfires / engine stalling at low revs.
Took to the Dealer and they replaced the Fuel pump AND High pressure pump on injector rail. That still didn't eliminate the issue and they then discovered the remap and flashed the ECU back to Std ("Version 2" which I pressume to be FR 200BHP software update).
After 2 weeks of perfect running (albeit back in the slow lane) the problem has re-emerged again and it's back at the dealer. (It also switches off the cruise control as it misfires).
One thing that did strike me though is it went horribly wrong immediately after I jetwashed the front end of the car (to get dead flies off) and I wondered if this was a sensor failure, which I seem to remember reading about somewhere.
Most of the probs have been starting during wet weather, (but then persists) you see.

Can anyone make any suggestions...I don't want the dealer to just blame the remap, which seems unlikely to be the cause...
Could it be engine temp sensor, coolant sensor, or coil packs on the TFSi ???

 

[Jedimaster65]

Aha ! Seat dealer has found the fault after 3 days of investigations.
Seems to have been a small crack in the PCV Valve, where the hose connects.
Trouble was the ECU was throwing up codes for all sorts of issues that were caused by this, like fuel pressure, (replace PRV, & camshaft sensor fault) etc.
Just goes to show the diagnostic won't always give you all the answers, more like a clue !
Hope this is of interest to anyone else that gets the same trouble...
Happy again !

 

[DanGB]

glad to hear its sorted. Only time ive had misfires is when a ignition coil went faulty.

 

[toledoChris]

Hi Guys,
I am new to the site and am finding it brilliant !
I have a serious misfire on my Leon TFSi Sport (18 months old).
I had an APR remap after 4 months (producing 260 BHP approx) and it has been fantastic for 12 months.
Now I have had a series of severe misfires / engine stalling at low revs.
Took to the Dealer and they replaced the Fuel pump AND High pressure pump on injector rail. That still didn't eliminate the issue and they then discovered the remap and flashed the ECU back to Std ("Version 2" which I pressume to be FR 200BHP software update).
After 2 weeks of perfect running (albeit back in the slow lane) the problem has re-emerged again and it's back at the dealer. (It also switches off the cruise control as it misfires).
One thing that did strike me though is it went horribly wrong immediately after I jetwashed the front end of the car (to get dead flies off) and I wondered if this was a sensor failure, which I seem to remember reading about somewhere.
Most of the probs have been starting during wet weather, (but then persists) you see.

Can anyone make any suggestions...I don't want the dealer to just blame the remap, which seems unlikely to be the cause...
Could it be engine temp sensor, coolant sensor, or coil packs on the TFSi ???

How did they spot the remap out of interest?

 

[Jedimaster65]

They drove it !
And they also say that they got some sort of ECU reset code, which was a sure pointer to a remap...

 

[daniel_owen_uk]

All APR remaps use encryption, which serve several purposes. First, it keeps prying eyes out of our software and prevents lesser companies from copying the chip and degrading the product. Secondly, the encryption prevents the dealer from flash programming the ECU. Also, all APR software is undetectable to a dealers VAG diagnostic tool.

First paragraph on their remap page, personally I would be going back to where you had it remapped.

 

[Jedimaster65]

More trouble ...

Thanks for that guys, but in the meantime it has all happened yet again !!!

Car off the road for another 7 days , but I am (tentatively) prepared to say I think the dealer has now finally sussed it.

Not the remap, but a faulty Engine RPM (Speed) sensor, kept over riding throttle idle settings and going haywire !

Seems to be quite normal again now, - hopefully !

But I do miss my remapped power...

 

[Jedimaster65]

I spoke too soon...

The misfire problems have come back, despite the dealer having even replaced the ECU under warranty !
So the APR remap was clearly in no way responsible for these isssues, as the car is now completely stock std, so what we have here is clearly not ECU related but some intermitent physical fault.
Again though, the misfire started during running in wet weather, which had me thinking Air Mass Sensor ?
The car is now throwing codes for G40 Cam sensor (as previously) but this was already replaced, as was the engine RPM sensor.
The PCV was also replaced, though, the car is also thowing a second code for low fuel pressure. The relays for the fuel pump were also repalced.
The dealer has been doing his best but this is clearly an elusive problem.

Do anyone have any ideas what the fault might be ?

It's been going on since June and am getting seriously cheesed off now...

 

[ValeriCUPR]

Hello,

I hope you are well , i have kinda same situation with my facelift Cupra R. The car has Stage2 map , i have misfires only on idle , and when i say only i mean that if i barely touch the pedal it goes away. New coils , new plugs , new injectors and hpfp(because of failed injectors) i have everything changed and still... misfires. Im staring to think that its something with the throttle body aliment. Still no idea what is going on and im staring to hate tfsi engines

 

[Brimfull]

Remove the map to see if that changes anything

 

[ValeriCUPR]

what for example can the remap do to cause misfires ? it does make sense but at the same time it does not so i will go again to tune it to 2+ but damn i want the powerrrrrr

 

[Brimfull]

Are you using 98 Ron?? Running a mapped car on 95 can cause misfires

 

[ValeriCUPR]

Actaully yes , when i drive it normally to work i dont use high octane fuel my bad..

 

[DanielCupra310Edition]

Hello,

I hope you are well , i have kinda same situation with my facelift Cupra R. The car has Stage2 map , i have misfires only on idle , and when i say only i mean that if i barely touch the pedal it goes away. New coils , new plugs , new injectors and hpfp(because of failed injectors) i have everything changed and still... misfires. Im staring to think that its something with the throttle body aliment. Still no idea what is going on and im staring to hate tfsi engines

Did you ever fix this I have the same problem and use 98 octane every tank...... stage 1 tuned.....