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'07 K04 GTI Misfires

BurgerGuy

Active member
Location
Charlotte, NC
Ride
GTI
Looking for some insight on this problem as I've been working through it since March. Am running Unitronic Stage 2+ RFD file on my BPY FSI with a ported/polished/ceramic coated K04. No changes to either wheel or wastegate. Since the K04 was installed, I have experience really bad misfires from ~5500RPMs and up when heavy on the throttle. It's so bad the car won't reach redline if you keep on the gas, but it pulls strong until it hits the "wall." Only codes that get thrown are the random/multiple misfires and then individual codes for cylinders 1 and 4. Also, whenever I crank the car up in the morning I can expect anywhere between 7-14 misfires across all cylinders. The car will pitter/putter and eventually crank up. It seems to take longer to get running on colder days.

I have done the following in an attempt to fix this:
  • Replaced and later rotated spark plugs and coil packs. Used R8 coils and the plugs recommended by Unitronic. Plugs gapped to .028. Misfires did not move when rotating
  • Rotated new S3 injectors. Misfires did not move
  • Ran compression test cold/hot. Everything looks good
  • New fuel filter. No change
  • Installed 145 bar FPRV. No change
  • Tested brand new APR HPFP. No change
  • Installed Unitronic intake/DV relocation kit. This helped quite a bit as I was running a BSH TruSeal from way back in the day
  • Installed latest revision rail sensor (06J906051D) and confirmed the sensor on the HPFP is the latest revision
  • Replaced LPFP and control module. Am running LPFP with part #1K0919051DB and controller with part #1K0906093J. This helped a lot, but the misfires are still present
I also ran some logs which the tuner is reviewing. They're attached to the post as a ZIP. Here's the car's setup @ 119k miles:
  • Unitronic intake/DV relocation
  • Rev. G DV with GFB DV+ internals
  • S3 injectors
  • APR IC
  • BSH PCV block off
  • APR HPFP
  • Latest revision MKV GTI LPFP and control module
  • 145 bar FPRV
 

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Pudding

Member
Location
UK
Other than the LPFP dropping to around 3.5 bar at 5500rpm and 99% throttle, everything else looks normal at a quick glance. Pressure only tells half the story as fuel volume isn't recorded, but clearly the LPFP is struggling at that load/rpm.

What spark plugs are you running?

With the cold starts, does cycling the ignition a few times before cranking it over help?

How does the crank/cam correlation look? Block 91 for live phase angle, should be 28KW for actual and specified, and block 93 (iirc) for static correlation, usually between 0 and -3KW. I've seen these numbers drift dramatically when someone gets the cam sprockets a tooth out following a chain replacement. That can cause the symptoms you describe.
 

BurgerGuy

Active member
Location
Charlotte, NC
Ride
GTI
Other than the LPFP dropping to around 3.5 bar at 5500rpm and 99% throttle, everything else looks normal at a quick glance. Pressure only tells half the story as fuel volume isn't recorded, but clearly the LPFP is struggling at that load/rpm.

What spark plugs are you running?

With the cold starts, does cycling the ignition a few times before cranking it over help?

How does the crank/cam correlation look? Block 91 for live phase angle, should be 28KW for actual and specified, and block 93 (iirc) for static correlation, usually between 0 and -3KW. I've seen these numbers drift dramatically when someone gets the cam sprockets a tooth out following a chain replacement. That can cause the symptoms you describe.
Am running NGK BKR8EIX.

I always turn on to accessory for ~5-10 seconds before turning it over otherwise it takes longer for the engine to start. I will try multiple cycles to see if that helps.

Should I monitor the crank/cam correlation while driving or when starting the engine?
 

clockwise33

New York Giants Fanatic
Location
NJ
A few things:

When I was battling K04 misfires on my APR tuned K04 setup I tried several different spark plugs and ended up finding that NGK PFR7S8EG gapped to 0.26 worked best, although I still get slight top end hesitation in cold weather. I plan on switching to a UM tune in the near future.

Your MAF readings are really choppy. Try spraying it out with MAF cleaner and, if no change, try doing a pull with it upplugged.

Do you have an upgraded boost sensor in the car? I see you hit 2560mbar a few times. I was under the impression that the stock sensor maxed out at 2550.
 

BurgerGuy

Active member
Location
Charlotte, NC
Ride
GTI
I recently did a throttle body adaptation which greatly improved the pedal and my morning cold starts are down to ~3-4 misfires on random cylinders. Still misfires up top like before, but the overall driveability and power continue to get better which tells me I'm heading in the right direction.

I've ran the car with the MAF unplugged in the past, but the problem didn't change/go away. Was running worse then so will try again and see if MAF cleaner helps any.

No upgraded boost sensor afaik.
 

carbonduc27

New member
Location
Stockton, CA
Ride
07 CW GTI 4dr Stage2
I had r8 coilpacks from amazon and ended up switching to oem gti coilpacks and that cured my misfire. The r8s never fit tight enough and I think that led to misfires on all cylinders. Once I switched to some coils that seemed to seat much tighter I was all good. Good luck with the troubleshooting.
 

BurgerGuy

Active member
Location
Charlotte, NC
Ride
GTI
Cleaned the MAF yesterday. It's running even smoother now, but issue still there. Will see what happens over the next day or so.

As for coilpacks, I'm using the ones the tuner recommended and the red cap R8 coils seem to work well. At least they don't die as quickly :)
 

snobrdrdan

former GTI owner
Cleaned the MAF yesterday. It's running even smoother now, but issue still there. Will see what happens over the next day or so.

As for coilpacks, I'm using the ones the tuner recommended and the red cap R8 coils seem to work well. At least they don't die as quickly :)
Are they legit/true OEM VW/Audi ones though?
That'll make a difference
 
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