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Tfsi fueling issue please help guys

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pudding:
Hard cuts are usually the result of too much boost or not enough fuel, or both.

Weird that the requested HPFP pressure is only 109.9 bar. That is stock pressure for an ED30 running 0.9 bar boost. I'm not sure what the stock rail pressure on the S3 is as they run 1.2 bar boost as standard.

Stage 2 should be around 130bar requested when nailing it.  That could be due to the ECU being unhappy and holding it back maybe.

I was getting crazy hard cuts running 1.7 bar. K04s surge badly if you cram in too much boost too soon and the engine can't swallow it, although that normally happens at 3000rpm, not 5K.  A bad crank sensor can cause a hard cut at 5K, but it normally fault codes that.  Can you drive through 5K with gentle throttle? If so, that outrules the crank sensor.

My guess is a fuelling shortfall but ideally it needs diagnosing on a dyno so you can load the engine up and watch what's happening in real time.

Requested and actual boost pressure and throttle position would be useful to log. You can then see what the fuel is doing at peak boost, but it's proper sketchy logging on the road. Too many clowns getting in the way.

08_edi30:
I did log the car back in the summer which included boost request and actual I’ll get the link and post it up for you to look at.

just been out for a quick blast while the roads are dead and the can feels like it’s being held back, it’s really weird, best way of describing it is it feels like the handbrake is on when accelerating so when foot off the throttle down on the clutch you can feel it being held back.


I’ll get the logs link posted shortly

08_edi30:
Here’s the link which also includes boost pressure

https://log.tunezilla.com/s/glzhPbKa

08_edi30:
another log I done back in the summer

https://log.tunezilla.com/s/MdsaixDc

I’ve just compared the logs to my old ed30 and the the s3 is not running as much a boost or fuel pressure as my old ed30.

pudding:
The requested boost and rail pressures in those logs would suggest a standard S3 map to me.  1.2-1.3 bar is about what a Stage 1 Eddy would run, but with 120bar rail pressure. 109.9 bar requested is usually a sign of a standard map. Yours did go over that slightly in places but that's just error margin due to the time it takes for the pump to react to ECU commands.

The holding back in boost sounds like a lean condition to me. No fuel, no power. It's that simple unfortunately. Although if it really is a standard or very mild map, the stock fuelling can cope with that, or it does if it's all in good condition.

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