'08 GTi FSI K04 Breaking up high RPM under load

[TSMILEY]

Greetings all! I am new here, and I am asking for help in what direction to look on my '08 GTi with APR K04. Under heady load (3/4 to full throttle) in upper RPMs, I am having an issue with the engine "breaking up" or missing. Of course once this start happening, I immediately let off the throttle to avoid engine damage. Below is a list of the modifications, and items replaced as well:

APR K04 Turbo and software
Run Flap Delete
S4 injectors
APR HPFP
GFB diverter valve spacer
3" downpipe & APR RSC exhaust system
Red Top coil packs
IE intake system

I have been researching this, and I have ordered an RS4 pressure relief valve, which should be in my hands within the next two days. Have you guys noticed this part to help with this issue? Also, I have NOT upgraded my intercooler yet, but I do have an OEM S3 unit ready to go in, however I am doubting this causing the issue.

 

[GIACUser]

Soooo did the car run fine at one point and this is a new problem? Or is this a new install that has not run right from its install?

Folks will all recommend that you get a Ross-Tech cable so you can read all the errors generated by the condition so you can properly troubleshoot it.

In the meantime let us know which plugs you are running and what gap you are running. And of course pull them all and check the gap. The gap will widen over time if you have been running this setup for a while. Too wide a gap can produce top end ignition issues like you have. Easy check

APR tune is expecting to see S3 injectors, not familiar with S4 injectors and how much they flow.

 

[TSMILEY]

Thank you for the reply! First of all, I meant S3 injectors. That was my mistake.

Spark plugs are as recommended by APR NGK BKR8EIX spark plugs gapped to 0.024" ±0.002" or 0.6mm ±0.05mm.

This is an issue I have had since installing the turbo about 10k ago. I don't drive my car very hard, and seldom full throttle accelerate to where I see this issue, so it's just been at the back of my mind until it happened the other day and I was abruptly reminded of it, making me ask the question.

I have checked for codes, and it has never set any, nor has a check engine light ever come on when it happened.

 

[ROH ECHT]

It's probably a weak coil. Since there are no misfire fault codes, nor any other, it will be a coil or improper plug gap. I would recommend replacing all of the coils to genuine oem. Not just any oem replacement. I had the same issue when I switched tunes from GIAC to Driver Motorsport and new oem coils fixed it along with PFR7B plugs @ 0.028".

1) You can try and open the plug gap to 0.028" first. Also, inspect plug condition for signs of lean or rich running while they are out.
2) If that doesn't smooth out the acceleration...the heat range of 8 plugs you have may be too cool and a 7 may be better.
3) Swapping out the coils for a known resistance coil may be next to try. See below....

Some aftermarket red top coils do not have the same resistance as genuine red R8 coils. R8 coils have a higher resistance of 5.3 ohm and our stock coils are 3.3 ohm. So, R8 require a tighter plug gap if car is boosted like ours is, and OEM coils require a wider plug gap. Aftermarket red top's resistance is unknown to me. Coils are one part that I stick with genuine oem and if you aren't melting coils...then why not stick with stock oem.

 

[BurgerGuy]

I would hold off on using that RS4 valve for now. Most OTS tunes operate at 130 bar which is the cracking pressure of the OE FPRV. Adding an RS4 valve will not net you any changes and could actually create more problems unless the tune is specifically designed to run higher rail pressure. I ran into similar issues when going K04 and later found it was one or more bad injectors. Got mine from eBay so maybe that's why. Anyways, picked up a new set of OEM Golf R injectors (same as S3) which resolved all misfire problems.

Would be good to pick up genuine R8 coils. Part number is 06E905115G. They're a direct upgrade to the FSI even at stock. Aside from that, make sure you're using the spark plug and gap that APR recommends with their tune.

What intake are you using? If MAF scaling is incorrect that can throw things off too.

 

[TSMILEY]

ROH ECHT, Thank you for the reply. My red top coils are in fact OEM VW Touareg/AUDI R8 coils. They are about one year old. I am NOT one to use non OEM parts, unless it is a high quality part (like APR ect). I also work in a VW dealership parts department, so, I get OEM at all times. I am going to try opening the gap up to 0.028 and see how that works out.

Burgerguy, I am using an Integrated Engineering intake. I was originally running another brand of intake, but went to the IE because of the MAF scaling I thought might have been what was going on. Unfortunately, that did not fix it....however it sounds SOOOOO much better than what I had! So it was still worth it.

 

[ROH ECHT]

OK, since they are genuine R8 coils, 0.024" to 0.026 would be recommended...you can try opening them first and if there's no difference...you may need to drop to a plug in the heat range of '7'. Stock heat range is '6'. The R8 at 5.3 ohm produces a thinner arc than that of the 3.3 ohm stock coil. Perhaps with the heat range '8' plugs and a 0.024" gap, the combustion isn't optimal. This is why I suggested inspecting for rich or lean when you remove the plugs...leaning more towards seeing it running rich. A bit dark from carbon. This could be due to a plug that is too cool.

BurgerGuy alludes to the MAF and that is another possibility...so do you have VAG-COM? A full-rev (2k rpm to redline) data pull to show the mass air just may be helpful to see what the MAF is reporting to the ECU. If the data shows mass air to be low, then the injector timing/duration within the tune may be being retarded. This may also point to a fading MAF sensor. My mass air is usually between 275 and 280 g/s in second gear and between 265 and 270 g/s in third gear. BurgerGuy may know his normal with a good MAF as well. Its mass air is roughly 80% of the known HP at the crank.

 

[TSMILEY]

ROH ECHT, Thank you again for the reply. I am going to inspect my spark plugs. I can honestly say that I believe I may be running rich as my car is white, and I typically get a descent amount of carbon on the back of my car after driving for a few days, especially if I am being a bit "froggy" in my driving. Also, under heavy throttle, I have seen dark exhaust behind me. So it definitely runs rich on hard acceleration.

I will advise on my findings after inspecting my plugs.

Also, I do have access to a VAG-COM through my job. After I inspecting, adjusting, or changing my spark plugs, if that doesn't take care of it, then I will get some logs. DO you know what values on VAG-COM I would need to use for this info?

 

[ROH ECHT]

MB/Group - 003 will log mass air: https://www.ross-tech.com/vag-com/m_blocks/001-009.html
MB/Groups in the 030s will log for lambda.

Instructions if needed...don't forget to select turbo: http://www.vaglinks.com/OBDII/Vag-com_Data_Logging_And_Graphing.pdf

 

[TSMILEY]

Thank you!

 

[GIACUser]

Just to add to the suggestions.
1. You state no error codes so you are not getting misfires or they would be listed.
2. Heavy black exhaust emitted under full throttle may indicate you are not getting a full burn of your fuel.
3. Stumbling is a bit more perplexing given no errors, but I would do a run/log as mentioned and run rpm and group 20 (per cyl timing status). ECU will pull timing and reduce power if there are conditions that put the motor in jeopardy. This will allow you to see what is happening in each cyl.

Adv Meas Values -> check 003 1-4 and 020 1-4
Run 4th gear flat out 2500 to redline

Again I would mention that pulling your plugs and having a look at them would be a good idea. If they are all rather carboned up I would suggest you drop down to a 7 heat range. NGK PFBR 7 is what I used on my K04 setup with very good results. I had very aggressive tune (336whp) and got good clean light brown plugs.

 

[TSMILEY]

GIACUser, Thank you for the information. I am going to try and do my logs as recommended by yourself and ROH ECHT either today or tomorrow. I am going to check my spark plugs first, and report my findings.

Thank you all!

 

[TSMILEY]

Hey guys, sorry I haven't had a change to run my logs yet, but hoping for today. However, here are my spark plugs pictured below. Thoughts? Defintely not running rich I don't believe.

BTW, the gap as removed is .025 across the board.

 

[TSMILEY]

I just opened the gap of my plugs to .028 to see if that will make a difference. I won't be able to test it out until this afternoon.

 

[GIACUser]

How old are plugs and with lighting I cant really see coloring of deposits on plugs.