Misfire Cylinder 6 (P0306 & P130A)

[fuzk]

This is a continuation of this thread.
I thought it was best to start a clean one, with all facts.

Haven't had the issue for a long time, but now it's back.

I hope, some one can point me in the right direction


When?
I believe that the lack of adaptation plays a role, as the issue comes after flashing the car.

I have observed the issue on both stock ECU tune and EPL stage 2.
The issue was there when the car was single pulley and now that it's dual pulley.

Manual downshift followed by light/medium acceleration is where it usually happens.
The issue seems to be triggered at mid range rpm (3300 - 4200) and part throttle.


Parts shuffling
I have moved injectors, plugs and coil packs around multiple times.
Misfire never occurred on any other cylinder than #6


Coolant leak
I never found evidence of IC leaking from supercharger or level dropping.
New ICs have now been installed in the supercharger
New gaskets everywhere (IC, SC, injectors) and new PCV.


Plugs
The plugs never looked hot or fouled.
New NGK PFR8S8EG gapped down to .026 installed multiple times.


Compression
#1 182
#2 179
#3 188
#4 182
#5 182
#6 184


Carbon buildup
Car has just been walnut blasted, clean as a whistle.


Exhaust and cats
Stock cats, 2.5" downpipes without baby resonators
Cat cores looked ok on a borescope, but I believe it's hard to tell (angle/image quality...)
Car just cleared MOT where the exhaust fumes are analyzed (NOx, CO, HC, CO2, O2).


Filters
New air filter and fuel filter (and LPFP)

6355 - Cylinder 6 
          P0306 00 [096] - Misfire Detected
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 190753 km
                    Date: 2022.04.20
                    Time: 19:48:47

                    Engine RPM: 3808.00 /min
                    Normed load value: 25.1 %
                    Vehicle speed: 32 km/h
                    Coolant temperature: 102 °C
                    Intake air temperature: 49 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 13.609 V
                    Unlearning counter according OBD: 40
                    Engine speed: actual: 3840 /min
                    MAF_ENVD: 315.92940 mg/stroke
                    Coolant temperature (unfiltered): 102.75 °C
                    Engine: operating status: PL
                    T_AST_ENVD: 77.10 s
                    Vehicle speed: actual: 32 km/h



7948 - Cylinder Disabling 
          P130A 00 [096] - -
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 190753 km
                    Date: 2022.04.20
                    Time: 19:48:47

                    Engine RPM: 4032.00 /min
                    Normed load value: 39.2 %
                    Vehicle speed: 34 km/h
                    Coolant temperature: 102 °C
                    Intake air temperature: 49 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 13.710 V
                    Unlearning counter according OBD: 40
                    Engine speed: actual: 128 /min
                    MAF_ENVD: 0.00000 mg/stroke
                    Coolant temperature (unfiltered): 101.25 °C
                    Engine: operating status: ST
                    T_AST_ENVD: 0.00 s
                    Vehicle speed: actual: 0 km/h

[MSq5]

This is baffling. You seem to have excluded all the "usual suspects". Maybe its the coil pack wiring harness or plug socket, since it stays with #6 no matter what else you do. Check carefully. Since the harness is covered, I don't know how to check for continuity ot shorts. Maybe a wire to the ECU is frayed or scraped?

Another thing: I'm assuming you are not using octane boost. That definitely caused the very same problem for me, including cylinder disabling until I turned it off and restarted the engine. The MMT in it coats the center electrode and interferes with spark. For me it always occurred first on cylinder #6 for some reason. Changed plugs, stopped using it, problem went away.

[markD76]

How are your valve cover gaskets? In good condition? No leaks?


Sent from my iPhone using Audizine Forum

[fuzk]

This is baffling. You seem to have excluded all the "usual suspects". Maybe its the coil pack wiring harness or plug socket, since it stays with #6 no matter what else you do. Check carefully. Since the harness is covered, I don't know how to check for continuity ot shorts. Maybe a wire to the ECU is frayed or scraped?

Another thing: I'm assuming you are not using octane boost.

I'm not completely sure that the cats have been excluded but they do seem to be doing their job cleaning the gases.
You are right, wires at the cylinder could be the culprit. They look fine, but I don't know how to measure it.

No, never used octane booster.

[fuzk]

How are your valve cover gaskets? In good condition? No leaks?

Zero oil leaks from valve covers (or anywhere else).

[dalmation53]

last time i had a misfire on cylinder #6 caused me an entire engine. please buy a cheap borescope on harbor freight and check your cylinder walls. my car still ran and drove with scored walls.

[fuzk]

last time i had a misfire on cylinder #6 caused me an entire engine. please buy a cheap borescope on harbor freight and check your cylinder walls. my car still ran and drove with scored walls.

Sorry to hear about your bad luck.
My compression is good so I don't think I'm having the same issue?

[dalmation53]

Sorry to hear about your bad luck.
My compression is good so I don't think I'm having the same issue?

Facts bro. It hurt my wallet but atleast I have my car back lol. Hmmm doesn't hurt to check man. But up to you.

[MSq5]

last time i had a misfire on cylinder #6 caused me an entire engine. please buy a cheap borescope on harbor freight and check your cylinder walls. my car still ran and drove with scored walls.

Not to derail the thread, but what caused the scored walls? And only on cyl 6?

[dalmation53]

Not to derail the thread, but what caused the scored walls? And only on cyl 6?

i havent taken apart yet. i don't know

[Shane Horning]

I had intermittent misfire on 2.0 aready but still good compression. One car the wiring harness was corroded at the ecu and the other car the intake cam rocker bearing on the roller was bad on the problem cylinder

[BobbyWatts]

Was there ever any update to this? I'm experiencing the same thing and have already ran through a long list of maintenance items.

New Plugs, coilpacks, injectors, and O2 sensors, compression test... ran fine and had it on the dyno for logging with nothing out of the ordinary after that work was done in May, then the same code/misfire popped up the other day at low rpm.

I'm catless, so i know a clogged one isn't the issue.

[SwankPeRFection]

Damn, that’s 2 people this week with single cylinder misfires that can’t be remedied who are running APR Stage 2 flashes. 🤔

[BobbyWatts]

Adding an update/solution to my issue - not the OP… it was a cracked intercooler in the supercharger leaking coolant into cylinder 6. It must’ve started as a very slight trickle causing the random misfires and took time to get progressively worse and more visible/identifiable.