Hi there.
My 2.2 DCI will not start. For some time I have had periodic start problems and it's now getting worse.
As there are so many things that could cause this, we really need more information and you really should get a diagnostics done first - not go jumping at conclusions like getting a TDC sensor which might be nothing to do with the problem. Once you have the fault codes that will give you a clue to where your problem lies.
Also when was the filter last changed? These can cause intermittent difficult starting if dirty and since they have long change intervals I have seen vehicles that only needed a new filter to start properly! Bear in mind that one of these common rail diesels needs around 200 bar pressure just to start and usually idle with around 300 bar if correct. Full pressure on the road can be as high as 1400 bar.
You may have one injection leaking pressure away, or a low pressure pump failing, or poor heater plugs, or electrical problems or... You see the problem?
If you fit a new TDC sensor yourself it MUST be fitted so that it is touching the flywheel. Do not back it away thinking it cannot be right for a stationary part to be touching a rotating one. It IS the correct way.
One other problem - has the TDC sensor modification been done in the past? If it has the new one may be a straight fit, but if not, you may have a plug and socket that do not match. Both wires in the loom to the sensor connection are the same white colour BUT the sensor is polarity conscious so be careful. Get them wrong and it definitely won't start!
Roy