APR Stage 2+ 2,0 TFSI Leon FR - random misfires and stuttering below 3.000 RPM

[BStones]

Hello Seatcupra.net

I have a 2008 Seat Leon 2,0 TFSI FR DSG, that's done 45.000 miles at the moment.

The problem is, that the car seems to make the required boost only above 3.000 RPM, where it pulls absolutely fine. Below 3.000 RPM I seem to get a lot of random misfires when accelerating at partial throttle. The car will buck and stutter like mad until I hit around 3.000 RPM after which, it will settle down and pull just fine.

When logging the car, I see that actual boost pretty far off from specified until the car hits around 2.800-3.000 RPM at which point the actual boost seems to catch up to specified. Fuel rail pressure is good and actual pressure keeps up with specified.

When running at WOT, I don't get as nearly many misfires, it's only really bad at partial throttle. Also, the problem seems to lessen a bit, once the engine is up to temp, however, if I idle for quite a few minutes and then pull away, it will buck again.

The car throws no fault codes.


The car is fitted with the following upgrades:

APR stage 2+ with RFD software
3" DP with 200 cell sportscat - stock catback
APR HPFP
Eurojet FMIC
BSH throttle body pipe
APR runner flap delete
Forge PCV fix and catch can kit

Within the last 1000 miles, the following things have been done in an attempt to resolve the issue:

New revision D original DV (switched from Forge FMFSITVR)
New cam follower
New N75 valve
New MAF sensor
New R8 coil packs
New NGK BKR8EIX sparkplugs - gapped to 0,028" as per APRs requirements
New coolant temperature sensors (both sensors changed)
Cleaned intake valves and removed carbon deposits
Oil change
DSG oil change


Have you got an idea?

As you can see, I've thrown pretty much every part (at least the one's I could think about) after the car at this point, and the problem persists.

I need someone to throw me a bone here - any ideas are very much appreciated!

Kindest regards
Bstones

 

[BStones]

Nobody?

 

[Dan FR]

Has it done it since having the map, or developed it since? Did it slowly get worse?

Firstly, specified will always be higher than actual at lower RPM, as the turbo still has to produce the boost and it needs a target to work toward

Secondly, are you sure they are actual misfires? Had the misfire counter running? if so, how many misfires are you logging?

Why are you running 8 grade plugs? Swap them back to 7's (BKR7EIX) and leave the standard gap. For future info you would have been better off with a Rev G valve, but that wont be contributing to your issues.

have you tried running with the MAF disconnected (electronically)?

Throwing parts at it is useless and costly. you need it diagnosed properly. Do you have VCDS? Data logging would be a very good start

 

[ibizacupra]

injectors seem to be getting more common for misfires..
along with coking up intakes..
plugs, coils, the usual suspects to ascertain.

multiple misfire or cylinder specific?

 

[BStones]

It's slowly gotten worse to the point where it is now, where I almost don't like accelerating unless it's WOT, as the symptoms are gone when going WOT.

I went with 8 grade plugs due to being adviced so - would 8 grade plugs over 7's be enough for me to experience such bad misfires?

When I had my old MAF, I pulled the plug on it, and the issue persisted. Fitted a new one though just in case, which (of course) did nothing to alleviate my issue..

Regarding the misfire counter, I did not get the exact number, as it was my mechanic friend who did the logging for me. He told me, that when going partial throttle, I got quite a lot of random misfires on all 4 cylinders.

I have logged it according to APR specs - 5 runs at WOT, and I have the logs on my PC if anyone would like to have a look. It's worth noting though, that the issue isn't there at WOT, so not sure what the logs are really worth....

Plugs and coils have 1000 miles on them - haven't resolved the issue. Intake valves have been cleaned 500 miles ago, so no carbon deposits. Oh and yeah - that didn't help either...

Would the injectors be a likely cause when I get random misfires in all 4 cylinders?


.... and lastly:

Yes, throwing parts at it has set me back quite a bit of money so far, and has gotten me absolutely nowhere. Hence why I'm turning to you guys as a last ditch desperate effort to resolve my issues

 

[ibizacupra]

I would be considering injectors at this point.. you've tried pretty much everything else

dont you just luv tfsi engines

 

[BStones]

That's what I'm doing - considering it.

However, I'm also considering the considerable (see what I did there...? ) amount of money I've thrown after parts in hopes of magically curing the mysterious misfires. And to be honest, I'm pretty tired of seeing no return at all on my financial investments in the car

Is there any way I can test the injectors as if to find out if they truly are to blame before shelling out a few hundred more £ on new injectors?


..... and yes.. I l"love" it. Never a dull moment

 

[Dan FR]

1 injector failing perhaps, but not all 4 simultaneously.... and not the smaller injectors for K03 cars. The larger injectors are becoming more and more prone to failure but rarely if ever hear of the K03 injectors failing.

If WOT logs don't show anything then it may be worth trying to log it when it is playing up, or put the car in to a specialist to be diagnosed which you probably should have done in the first place

 

[BStones]

Gotcha Dan!

I just want to bounce an idea off you guys - I put in NGK BKR8EIX spark plugs - 2 steps colder than stock afaik. After that, the problems have seemed to develop.

Mostly I drive quite sensibly and it's pretty rare that I actually drive my card hard.

Could it be, that the symptoms I'm experiencing are due to the plugs being too cold for my driving pattern and current tune?

Regards

 

[Dan FR]

Yes it could well be and it wouldn't be the first time i have heard of it. Do you have your old plugs still to try?

 

[BStones]

Nope, I don't have the old plugs. Think I'll just order a set of BKR7EIX's and throw em in. If it doesn't cure the misfires, I'll at least have put ind the correct temp plugs for future reference.

 

[ibizacupra]

Gotcha Dan!

I just want to bounce an idea off you guys - I put in NGK BKR8EIX spark plugs - 2 steps colder than stock afaik. After that, the problems have seemed to develop.

Mostly I drive quite sensibly and it's pretty rare that I actually drive my card hard.

Could it be, that the symptoms I'm experiencing are due to the plugs being too cold for my driving pattern and current tune?

Regards

thats a little colder than I would use for your state of tune

 

[BStones]

Put in a set of correctly gapped BKR7EIX's today, and the problem persists.

Next order of business will probably be a new set of injectors (migt aswell go S3 injectors and do the K04 upgrade while I'm at it) and hopefully that will cure my problems.

 

[LucaFR86]

Bstones, you have solved the problem of misfire?