2014 CKRA knocking//pinging, hot&cold, only above 1600rpm

I have 2014 Passat TDI (CKRA) running Malone Stage2 and RawTek "eco kit", garaged at night. This winter on REALLY cold mornings (15-20F) I began to hear faint knocking and pinging noises under light acceleration above 1600rpm. Once warmed up it went away. Running 50cetane SouthernStates fuel made it go away completely, hot or cold. 5months later it is always present, hot or cold, and is really pronounced on cheap 40cetane truck fuel. Almost sounds like preignition. No error codes, no faults. No huge variation in cylinder torques, compressions, location of primary ignition, fuel metering, etc. Rail pressure good. All sensors working. Mileage steadily decreased from 60s highway to mid 40s. Sticky/film soot in tailpipe (not powdery) yet no oil being lost or burned. Perplexed. Not normal sounds, and I've had this since new at 47miles.

Check injection timing in VCDS? Dunno. Other than this, runs great on highway, but miss my mileage.

How better to troubleshoot?????

With the ECU software heavily modified and non-stock exhaust components, the first person I would ask for trouble-shooting advice is the tuner. Either that or revert the thing back to stock configuration and see how it runs then.

-Uwe-

Yes, I had thought that and even tried that. No change. Issues and observations same. They actually started before the mods. Only 50 cetane and a warmed up motor squelch it, but still barely perceptible and lower mileage. Sensor somewhere but haven’t ferreted out that yet. Ideas??

CO2N0x said:

They actually started before the mods.

Click to expand...

I agree with Uwe; put everything back to stock, sort out the problem with known working diagnostics (tuners are often "less than careful" with keeping diagnostic code working fully), then (if you must) revert back to your current FOD state.

After reverting to stock pleas post a full unedited VCDS Auto-Scan so we can see all the fault codes and hopefully someone will have some helpful suggestions how to cure the problem(s).