Hesitation, Misfires on S3 APR Stage 3+ kit

[beflythis]

thanks in advance if you're reading this...

virtually new 2016 S3 (20k miles to date), Stage 1-> Stage 3 (EFR turbo) at roughly 15k miles. Ran and pulled like a beauty, so wanted more and went 3+ with the fuel injector kit and new APR tune for 3+.

However, 3+ not been so fun. Getting 3/4 cylinder misfires on WOT between gears 3 and 4 at around 80-90mph (or less if car is cold and I smash). This is always preceded by turbo audible/physical hesitation and sputtering, then car goes into LIMP mode and CEL (giving Cylinder 1, 3, 4 misfirse always) before restarting. Here's where it gets interesting: this is symptomatically only triggered with SUSTAINED or longer WOT. I can traffic drive and give short bursts of WOT without triggering limp mode/misfires. However, it seems that when I'm holding WOT for 3-4 seconds or more (truly smashing it), that's when I start getting hesitation, sputtering followed immediately by LIMP and CEL.

What I've done so far (with no change in symptom):
1. Checked spark plug distance (yes I am on the NGKs that came with the 3 kit) and re-set (a few were off so we re-set all to .022)
2. New RS3 coil packs (nice clean pulls but still no change)

Shop guy thinks it may be the OEM fuel pump controller shorting out (power issue/failure) under WOT causing the car go to limp mode. In the spirit of supporting the beastly HP that comes with this kit, i've made the decision myself to buy a Torqbyte MQB High Power LPFP Driver Kit to support the fuel load/request with the 3+ kit.

Know there are lots of seasoned folks on these forums, so would love to hear thoughts. The shop has the data logs where we used the APR dongle to capture three 'limp mode' triggers of this situation. happy to share if desired.

please help me return to happy WOT smashing!

[P2WRTMR]

thanks in advance if you're reading this...

virtually new 2016 S3 (20k miles to date), Stage 1-> Stage 3 (EFR turbo) at roughly 15k miles. Ran and pulled like a beauty, so wanted more and went 3+ with the fuel injector kit and new APR tune for 3+.

However, 3+ not been so fun. Getting 3/4 cylinder misfires on WOT between gears 3 and 4 at around 80-90mph (or less if car is cold and I smash). This is always preceded by turbo audible/physical hesitation and sputtering, then car goes into LIMP mode and CEL (giving Cylinder 1, 3, 4 misfirse always) before restarting. Here's where it gets interesting: this is symptomatically only triggered with SUSTAINED or longer WOT. I can traffic drive and give short bursts of WOT without triggering limp mode/misfires. However, it seems that when I'm holding WOT for 3-4 seconds or more (truly smashing it), that's when I start getting hesitation, sputtering followed immediately by LIMP and CEL.

What I've done so far (with no change in symptom):
1. Checked spark plug distance (yes I am on the NGKs that came with the 3 kit) and re-set (a few were off so we re-set all to .022)
2. New RS3 coil packs (nice clean pulls but still no change)

Shop guy thinks it may be the OEM fuel pump controller shorting out (power issue/failure) under WOT causing the car go to limp mode. In the spirit of supporting the beastly HP that comes with this kit, i've made the decision myself to buy a Torqbyte MQB High Power LPFP Driver Kit to support the fuel load/request with the 3+ kit.

Know there are lots of seasoned folks on these forums, so would love to hear thoughts. The shop has the data logs where we used the APR dongle to capture three 'limp mode' triggers of this situation. happy to share if desired.

please help me return to happy WOT smashing!

How are you monitoring boost?

[Spinnetti]

Ah APR... I used to get limp mode under hard braking of all things. After thousands of my money spent turned out to be coding issues at APR that was eventually corrected (A4 1.8t years ago)... I'm not confident their stuff is debugged very well after two different sets of issues with their products over the years... Interested to see how it all comes out though.

[beflythis]

How are you monitoring boost?

have an APR dongle that was capturing data. however, not running an aftermarket boost tap if that's what you're asking.

[liljonny16]

I had a very similar issue with my K04 CC. From day one sometimes when I was backing into a parking spot the car would die. Not during WOT but only when I was backing into a parking spot. Super weird. Took it to the dealership, no error codes. They just sent me on my way. At around 22K miles, I installed the K04. After the K04 install while doing WOT in 3rd and 4th the car would go into limp mode sometimes but not every time. Finally, at around 38K(of course right after the warranty ends), the HPFP died on me. I was on the highway and went to make a pass and I had no power. Luckily, it was documented with the dealership at around 900 miles, so they reimbursed me.

[P2WRTMR]

have an APR dongle that was capturing data. however, not running an aftermarket boost tap if that's what you're asking.

You should get a tap and check how much boost you are running.

[613B6]

We would need to see a WOT log of all the relevant data (RPM, lambda, timing, correction, low and high fuel pressures, PUT/MAP values, etc) otherwise everyone is just guessing. If your running the 305 pump, chances are you are fine without the PM3. PWM controllers seem to be crapping out or dropping pressures on the 450 pump.

[beflythis]

Link to drive with the spreadsheets. I've captured most if not all of what you're asking, I believe.

I've got a remus responder (sprint booster) on the throttle which is why you will see high throttle with low pedal angle. (sensitivity is set high). thanks for the attention.

[chris164935]

When did you install the Remus Responder? Have you trying removing it and letting the ECU deal with all throttle control?

[beflythis]

I've had it on since stage 1. No issues at either Stage 1, or stage 3 with just the EFR big turbo kit. Only CEL /misfires since 3+.
Also, another 2015 S3 that's Stage 3+ (including Methanol) with the same APR hardware and tune in my area is experiencing the exact same CEL/misfires issue. He's even had a replacement fuel pump sent by APR, too. Was originally at higher speeds, and with time, can be triggered at lower speeds now, too (just like my symptoms).

It does make sense to data test without the responder so I'll disable that and see if I can trigger.

[chris164935]

I can't view the logs from my phone, but what do the air/fuel readings look like right before the problem starts?
Are there any other DTCs stored after the issue occurs?
Are you running more boost since going from Stage 3 to 3+?
I'm still learning about these cars myself, but is there any way to see what the fuel pressure is during this time? Or, can you install a gauge to check pressure while on a Dyno? That might be cheaper than replacing the fuel pump controller to diagnose the issue.
Also, have you tried lowering the spark gap or maybe running a multi ground spark plugs?

[theweebabyseamus]

Pull the Remus and see what happens.

[beflythis]

Remus turned down (in sensitivity) AND new torqbyte fuel controller module in (stock out entirely), no more misfires. when turning responder up to 3'ish (what it was at with frequent misfires) i get a little bit of 'chuffing' still when going between gears (holding WOT between gears), but that's it. pretty clean pulls when it's lower and no misfires yet.