Little power at low gear & high rpm

[njoshea]

I see variations on this theme on other posts, but not quite the same problem. Here goes:

I have a 2005 Mk6 2.4tdci. I had the turbo replaced recently, and wow-wee, it goes like the clappers now at the top end of the speed range.
But, in low gear & high rpm its a shocker - low power, blowing black smoke at high rpms & a deeper, throaty note to the engine at those high rpm's.
So, diagnosis time:
1) I checked the EGR - it was filthy. I installed a blanking plate to see what would happen, and it ran like a charm (whats that telling me? No good ideas - any theories?)
2) The EGR must be stuffed. so I replaced it with a new one & removed the blanking plate. No change - back to poor performance at low gear/high rpm.
3) OK, is it starved of air when it needs it most? I replaced the airfilter and confirmed air & intercooler hoses were good. No change - still poor performance at low gear/high rpm.
4) Hmm, is it the exhaust side? I went to a muffler shop, they checked both catalytic converter and mufflers. They're all good.

Ive run out of ideas. Any other thoughts out there? Cheers.

[knobby1]

Have you had the codes read..?? Glow plug light flashing..??

Lord Knobrot

[njoshea]

No engine light warnings.
No codes from my scan tool. But, I'm reading on here there are scan tools and then there are scan tools. So, upgrading my capability to use FORScan at the moment.

[apartransit]

Not sure if helps, but try to check pressure demanded from pump to injectors. This could help if you se huge pressure difference between pressure provided and pressure demanded,pressure regulator is faulty.

[knobby1]

Not sure if helps, but try to check pressure demanded from pump to injectors. This could help if you se huge pressure difference between pressure provided and pressure demanded,pressure regulator is faulty.

Mk6 TDDi doesn't have a fuel pressure regulator like the Mk7's.

Lord Knobrot

[njoshea]

Some musings while I wait for the modified ELM327 to turn up...
The improved low gear/high RPM performance with EGR blanking is telling me something...
Turbo is 'new' (reconditioned), EGR is new, cylinder rings were replaced a couple of years ago, injectors were called good at the same time, silencers & catalytic converter are clear. Is there any other mechanical item Ive overlooked?
Assuming the 'hardware' is good, then I guess it must be sensors...looking forward to the code reader turning up!

[knobby1]

Some musings while I wait for the modified ELM327 to turn up...
The improved low gear/high RPM performance with EGR blanking is telling me something...
Turbo is 'new' (reconditioned), EGR is new, cylinder rings were replaced a couple of years ago, injectors were called good at the same time, silencers & catalytic converter are clear. Is there any other mechanical item Ive overlooked?
Assuming the 'hardware' is good, then I guess it must be sensors...looking forward to the code reader turning up!

Mk6 TDCi's are known for pumps eating themselves.

Lord Knobrot

[njoshea]

FORScan is pretty cool. I went for a run and plotted some data:

test-19-05-22.jpg

Nothings leaping out at me yet. Although...Engine Cylinder Temperature (ECT) looks kinda low doesnt it?

[njoshea]

Well, the engine temperature was too low - the thermostat was buggered.
So, engine temps are back up where they should be now, and while vehicle performance does feel better, the fundamental problem of black smoke on accels remains.
Per the suggestions on here, I'll investigate fuel demand vs actual next.