VW Sharan Diesel Power Loss & High Fuel Usage Fix

Had a similar issue with my 2009 VW Touran 2.0 TDI. The symptoms match exactly what I experienced, poor fuel economy and significant power drops, especially under load. After thorough diagnosis, the problem traced back to two issues: worn piston rings causing compression loss and a partially clogged fuel injector. The compression test confirmed cylinder pressure was well below spec. These symptoms are common in these engines when they reach higher mileages. The repair involved: Removing cylinder head, Replacing all piston rings, Installing new fuel injectors, Timing belt replacement while engine was apart This was a major repair requiring engine disassembly. The car runs perfectly now with restored power and normal fuel consumption. The work took about 4 days in the shop. Would strongly recommend getting a compression test done first, its the most reliable way to confirm if piston rings are the culprit. Also worth checking fuel injector spray patterns, as poor atomization can cause similar symptoms. These engines are generally robust, but piston ring wear is a known weak point that needs addressing when it occurs.

Thanks for sharing your experience with the engine rebuild. My crankshaft bearings were also making knocking sounds, so I had them replaced during the piston ring job, seems like catching problems early saved me from more extensive damage. Just wondering, what was your final repair cost? And has everything been running smoothly since the work was done? Im particularly interested because Im starting to notice some similar issues with my Sharan and want to budget accordingly.

Got my VW back from the mechanic last week and can give you an update. The cylinder pressure fluctuation that caused the power loss was actually traced to a faulty turbocharger control module, not the engine internals. Since this was a consequential error from a previous repair they did, the shop fixed it at no cost (0€). The engine knocking sounds I mentioned earlier completely disappeared after they corrected the turbocharger settings. Fuel consumption is back to normal and power delivery is smooth again. The camshaft timing is spot-on now too. Running much better than when I first noticed the issues, no more check engine light or performance problems. Regular maintenance really does help catch these things before they become major repairs. The fuel injectors are working perfectly now that the boost pressure is properly regulated.

Finally got my car back and wanted to close out this thread. After checking around, I found a specialized VW shop that properly diagnosed the issue. Turned out my problems werent as severe as initially feared. The intake manifold had multiple small cracks causing pressure leaks, and two fuel injectors needed replacement due to carbon buildup. Total repair cost came to 800€ including parts and labor. The turbocharger and crankshaft were both checked but were functioning fine. Shop completed everything in two days. The car runs great now, fuel consumption is back to normal and power delivery is smooth. The check engine light hasnt returned. Definitely worth getting a second opinion rather than jumping straight to major engine work. Really glad I asked here first and got some perspective on possible causes.