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MK7 Misfire issue higher rpms

M

Mk7casey

Passed Driver's Ed
Location
Delaware
Car(s)
2021 Cornflower GTI
Let my introduce myself, name is Casey, I have a 2017 VW GTI FBO IS38 E85 was originally APR IS38 tuned but wanted more power so I went with a custom tune, car has been great to me over the few years I have had it, this is the first thing that I really cannot seem to figure out an answer to as far as diagnosis and it sucks.


IMG_4239.jpeg




OEM IS38 TURBO
ETHANOL CONTENT SENSOR
HPA HPFP
WALBRO 450LPH PUMP
APR IGNITION COILS
COLDER SPARK PLUGS GAPPED TO .020
CTS TURBO INLET PIPE
APR CARBON INSTAKE
STAGE 3 SOUTHBEND DAILY CLUTCH
BILLET REAR MAIN SEAL
USP MOTORSPORTS STEEL CLUTCH LINE
APR SHORT SHIFTER
APR DOWNPIPE
STRAIGTPIPED WITH SPARK PLUG DEFOULERS FOR SECONDARY O2
APR DOGBONE MOUNT
034 UPPER DOGBONE INSERT
034 STREET DENSITY MOTOR MOUNTS
APR SWAY BARS FRONT AND REAR
APR SILICONE BOOST HOSES
NEUSPEED HIGH FLOW DISCHARGE PIPE WITH MUFFLER DELETE
NEUSPEED RSe05s

Car is tuned by SneekyTuned

I am having an issue where my car will misfire starting around 5500-6500 sometimes it pops an epc light and i have no throttle and the car sounds like it is running on 2 cylinders.
I have ruled out fuel because the ethanol tested at 84% ethanol, spark plugs have been changed and properly gapped and i just put in brand new rs3 coils.

codes are as follows
P0300 P0301 P0302 P0303 and P0130A - Hide cylinder

Here is my most recent log it didnt pop a epc light but i could still feel the misfires
DATAZAP LOG
 
Diggs24

Diggs24

Autocross Champion
Location
de plains! de plains!
Car(s)
2015 GTI
There's only so much of an injection window up top there. Fueling from the pumps isn't an issue as rail pressure is good. It's quite a stout tune. E85 on an IS38 is hard to nail down without MPI. It's always right on the edge of what the DI injectors can handle. Some cars can get away with it, mainly because their pumps are probably not 84% E. OR they run a bit less boost. Try and cut in some pump gas and see if that alleviates it. Heck, you'll get a bit better mileage, lol.

Do like a 10/2 split on an empty tank.
 
M

Mk7casey

Passed Driver's Ed
Location
Delaware
Car(s)
2021 Cornflower GTI
Diggs24 said:
There's only so much of an injection window up top there. Fueling from the pumps isn't an issue as rail pressure is good. It's quite a stout tune. E85 on an IS38 is hard to nail down without MPI. It's always right on the edge of what the DI injectors can handle. Some cars can get away with it, mainly because their pumps are probably not 84% E. OR they run a bit less boost. Try and cut in some pump gas and see if that alleviates it. Heck, you'll get a bit better mileage, lol.

Do like a 10/2 split on an empty tank.
Click to expand...
=
Gonna try mixing E60 in my tank and see what that does for me, I was on e60 when i was running the stock lpfp.
 
M

Mk7casey

Passed Driver's Ed
Location
Delaware
Car(s)
2021 Cornflower GTI
Diggs24

Diggs24

Autocross Champion
Location
de plains! de plains!
Car(s)
2015 GTI
At lower rpm the window is bigger. e85 has lower stoich so you must inject more. as rpm climbs there is less time to inject. it wants to hit afr target but can’t because there isno more time to inject fuel needed. leans and misfires. look at my first post you can see where it leans. less e85 means less fuel needed to inject. pulsewidth lowers. injectors happy.
 
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