2007 Passat 2.0TDi (PD140) - PD140 wont start

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Thu 27 Jun 2013 15:41
2007 Passat 2.0TDi (PD140) - PD140 wont start - PD140SA

Hi guys, I am new to the forum and hope to learn as well as contribute. I own a 2007 Passat 2.0TDI manual (the PD140 version). At the moment my car is a non-runner and I am really desperate to understand why. Here is a brief history of recent events (apologies in advance for the lengthy post). About 6 weeks ago I had the unfortunate event where my cylinder head cracked between the exhaust port and water jacket. Fortunately the bottom end did not overheat and was undamaged, but the repair was very expensive and took a while to get fixed. Once fixed the car ran beautifully without any problems. Two weeks ago I noticed the engine check light (yellow light that looks like an engine) coming on and staying on. So I took the car back and the scan showed a glow plug error. Due to logistical reasons I had to continue driving it for two weeks, but without any problems (no starting difficulty, running smooth, etc). This past Friday I took it back to the workshop to have the oil drained after the head replacement. When I collected the car in the afternoon, it started fine and no warning lights lit up. However, 5km’s down the road the car suddenly lost power (like when you lift of the throttle pedal) and the little engine light came on again. I lightly touched the pedal again and then had a “Electrical Fault Workshop!” on the display after which the glow plug light flashed and the engine died. After this it would not start at all. The car is back at the same workshop for the past week and they have scanned it with three different scan tools and cannot find an error code. They checked every single connector, sensor and fuses, and all are working. They confirmed that all glow plugs are lighting up, the injectors are receiving a pulse signal and the lambda sensor reads. They also checked the lift pump in the tank and it is pumping, and the injectors are receiving diesel. They bled the fuel system to ensure no air is trapped somewhere. I am really desperate and they don’t seem to find the fault. Has anyone experienced anything similar and does anyone have any suggestions where to continue looking for the fault. The last switch to check is the brake light switch and this will be done today. I will be taking the spare key to them this afternoon in desperation (maybe the current key “lost” its coding?). Sorry for the long post, but I am desperate for any help. Thanks,

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Thu 27 Jun 2013 15:57
2007 Passat 2.0TDi (PD140) - PD140 wont start - 659FBE

This is a difficult problem to diagnose remotely.

Bearing in mind that the head has been off recently, my first step would be to do a careful and basic check of cam/crank coordination. You can fit the cam locking tool in situ and observe the crank position using the flywheel TDC mark - on some transmissions. If you are absolutely 100% sure that the mechanical timing is correct and also that there is feed pressure to the injectors from the tandem pump (test n i p p l e on pump), there are two other areas to look at.

If the injectors are receiving a "pulse signal" this needs to be assessed according to whether electromagnetic or peizo injectors are fitted. A loop current probe will test the Bosch electromagnetic injectors - which hardly ever fail. Peizo injectors are voltage operated and are prone to failure. Although 4 injectors failing is beyond probability, bear in mind that the inverter for the peizo units is common to all 4 - which is why these engines stop when sooty engine oil gets into the injectors and shorts them out.

Lastly, my favourite. Check that the intake flap motor has not broken its cogs and stuck shut. This cuts off the air supply to the engine to make it stop smoothly - but it's supposed to open again when you want to run it...

The 1.9 engine had a super-reliable vacuum operated flap to do this job.

Let us know what it was when you find it.

659.

Edited by 659FBE on 27/06/2013 at 16:01

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Thu 27 Jun 2013 16:13
2007 Passat 2.0TDi (PD140) - PD140 wont start - PD140SA

Thank you 659. I am happy that the mechanical timing is correct as the car ran beautifully for four weeks after the head replacement. They also fitted a new cambelt, so there should not be a problem with belt tension or missing teeth.

I will propose checking the peizo inverter - should this not have appeared as an error code?

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Thu 27 Jun 2013 16:41
2007 Passat 2.0TDi (PD140) - PD140 wont start - 659FBE

For the time it takes, I would very strongly recommend a basic timing check. Obviously, I have no knowledge of the standard of workmanship applied to your job, but I vividly recall advising a fix to a 1.9 PD which had had a belt change a month previously, ran well - and then stopped. The monkey responsible had turned the cambelt tensioner in the wrong direction (there's an arrow on it) to tension the belt. It failed and repairs were extensive.

I lost interest in the PD when the Siemens injectors appeared - so I can't help you with the codes. One shorted injector will shut down the whole lot. (Thoughtful design, subject to recall).

You could unplug the injectors one at a time and see if the engine starts up on 3 cyls. (It will, if otherwise OK).

Remember, engines need air as well as fuel.

659.

Edited by 659FBE on 27/06/2013 at 16:45

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Thu 27 Jun 2013 17:48
2007 Passat 2.0TDi (PD140) - PD140 wont start - Peter D

I suggest you post this on the VWAudiforums.co.uk Does it sound normal when cranking and has someone checked the cam belt. Do not keep cranking the engine as you may be injecting fuel and can hydraulically lock the engine and bend a con rod. Regards Peter

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