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I own a Peugeot 206 (2008) with a 2.0 hdi engine (I believe the engine code is DW10TD) with a Siemens fuel system.

After changing the fuel filter, I turned it on and found it was idling a bit rough. After turning the key back off it kept on running for a few seconds before deciding to shut down, which is completely abnormal.

I read that this behavior might be due to a faulty sensor in the high pressure line, and my guess is there's air trapped interfering with this sensor. However my understanding is that this particular family of fuel systems bled themselves out without much intervention, by simply turning the key a couple of times before cranking the engine.

So my question is whether this guess makes sense and if it may be possible to drive it to the shop without blowing up expensive stuff. I didn't keep it running for long fearing the latter, so perhaps it would clear after leaving the engine running for a while?

Thanks in advance.

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  • Welcome to Motor Vehicle Maintenance & Repair! Aug 4, 2023 at 21:08

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The problem is air in the fuel system. To prevent this in the future, fill your new fuel filter with diesel fuel before you install it. There is probably nothing wrong with the fuel sensor. Eliminate the air to solve the problem.

The quickest way to eliminate air is to slightly loosen the fuel connector on each injector, cover all the connectors with rags to catch any fuel spray, and then crank the engine for 10-20 seconds to purge the air from the fuel lines. Now remove the rags, tighten the fuel lines at the injectors, and the engine should start normally.

Idling the engine with air in the fuel lines might not remove all the air because idling requires only a little fuel flow. Air can get trapped at a high point in the fuel line and never get forced out of the line until fuel flow is much greater.

With air in a fuel line between the high pressure pump and the injector, the fuel line acts like a pressure reservoir. This is why the engine continued to run after turning it off -- there was still pressure in the fuel lines that the compressed air was able to force out of the injectors.

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  • Worked like a charm! Just in case I also disconnected the injector cables. Thank you for the thorough answer! Aug 7, 2023 at 0:40
  • @SandroPastorini Excellent! Glad it worked out for you, and thanks for the feedback.
    – MTA
    Aug 7, 2023 at 0:47

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