Problem was caused by faulty software from APR.
Installed GIAC software and have not experienced ANY misfires since.
I've got an APR K04 with a few extra upgrades, and whenever I'm at WOT I get misfires at 5,500 RPM. I've verified this on and off a Dyno.
I've read several threads on this subject, and most end with lots of great suggestions and no real follow up or conclusion. I'd like to start a new thread for those of us still having this issue, and hopefully we can get to the bottom of this.
Car: 2008 Audi TT Coupe with 50,000 KM
Engine: 2.0T FSI (BPY)
Software: APR K04 testpipe & Unitronic STG3 DSG
- APR K04, APR HP Fuel Pump, S3 Injectors
- H2Sport Cam follower fix
- RS4 Fuel pressure regulator valve (079 130 757)
- APR Intercooler
- Labonte Motorsports MAF Water/Meth (40/60) (Injected just prior to intake manifold)
- Neuspeed K04 hiflow air intake
- AWE Turbo Back exhaust w/ metal 200 cat
- Peloquin Differential
- Various stiffeners, etc.
Most of my work has been done at H2Sport, even if I had to supply some of the parts.
A little background:
This car was purchased early this year with the intentions of turning it into a track car. We have been doing the upgrades in steps, with the hopes of ironing out any bugs or problems that arise. As you can see from the above list we were almost finished with the powertrain upgrades when we hit this problem. I've been working with the folks at H2Sport over the last few months trying to identify the cause of this problem. The last upgrade performed was the exhaust, and we're fairly certain the misfires were NOT happening prior to the installation of the new exhaust.
Extensive logging has been done by both myself and H2Sport. We have verified that during misfires Boost is good (ie: actual 2410 vs. specified 2450). I can't remember all the remaining tests done, but it's been hours and hours of logging and testing and we can't find anything that stands out.
Things already tried:
- Replace coilpacks
- Replace and gap sparkplugs (OEM)
- Replaced the in tank fuel pump to latest revision
- Remove the intake manifold and clean the valves (WM really does do a great job keeping these clean!)
- Check fuel rail pressure (Always hits 130bar when misfiring, upgraded to S4 valve. Now logging 136bar - still misfires)
- Enabled / Disabled Water Meth. Tried 100, 93 and 91 APR modes. Always misfires.
- Set the software to "Stock" - NO MISFIRES
- Cursing at it
Moving forward, I'm having the Air intake modified and a custom airbox made to hook up to the factory air source in the grill. The original need for this was to stop the intake from drawing in heat from the engine compartment. However, it has been suggested the intake itself may be the problem as the APR software does not know how to deal with such a high flow rate and this may have been exacerbated by the introduction of the AWE exhaust. So, I'm hoping the added restriction of the airbox and limiting it to the factory air source may help? If, after installing the new airbox, I still have the misfires I will switch back to the factory intake (with a drop in K&N) and see if that helps. I do get MAF codes, on rare occasions, however only at track speeds and WOT.
The last suggestion i've been given is my exhaust springs are too soft. If everything else fails I will move to the final planned step on the engine and replace the valves and springs.
If you are having this problem aswell, please post up everything you've done to your car and everything you have tried to fix it.
Thanks for reading this long, drawn out post! I'm looking forward to hearing any new suggestions!