TDI Non-starting after timing belt change

[claude626]

Help required:

I have replaced the timing belt and water pump on my 2007 Passat TDI 125kw. I used a locking kit to set the timing gears in position and I am convinced that it had not shifted during replacement. I followed the factory instructions also. All I disconnected on the engine was the battery and the fuel lines through the filter.

Heres the rub though, after replacement I cannot get the thing to run properly.
I removed the filter cover to find it completely blackened. I replaced the filter, and still nothing. pulled the in tank lift pump assy to find the fuel in the tank was jet black. googled this and found the known issues with the tandem pump. purchased replacement pump from AFI, fitted and still it will not start.

This is what I have done up to this moment:

I tried using areo-start. we got it running but very rough and making smoke. it will not start normally though.

I have locked and unlocked the car before trying to start it
I can confirm fuel flow to the tandem pump out of the fuel filter.
I tried externally powering the lift pump.
I have pluggged in an OBDC reader, and there are no stored or pending DTC's.


Any further advice or hidden tricks ?

[Umai Naa!!]

Does the lift pump in the tank actually work? These are known to die, and don't show their symptoms until you open the fuel system and try to restart the car.

Does the engine turn over >280rpm when cranking?

[claude626]

I can externally power it to prime the system, so I guess yes.

I am using an battery trolley to provide extra ooomph. what is critical with the cranking rpm?

Thanks

Claude626

[Umai Naa!!]

It won't fire the injectors below 280rpm.

[daniel8810]

I did my belt the other day on 2012 passat.

I must say surely this problem with your car isn't related to the timing belt replacement?

1) Make sure entire fuel system is primed; must be no air pockets or bubbles in system.
2) Tandem pump seals could be faulty/worn.
3) Check if you have plugged in all sensors after TB replacement (although you sometimes get a DTC and sometimes dont)


Because your diesel fuel is very black as you say, could we see a photo of the filter when you removed the cover?
This is why i stick to certain diesel fuel brands such as shell and caltex.


Its always good to run a good brand of diesel (as mentioned above) and sometimes use diesel injector cleaner, and replace your diesel fuel filter as per VW recommendations. Depending on your country.

[Bora Sport]

You need to get it scanned but from experience I would be checking that the adjustment of the belt hasn't moved a bees **** and the cam position sensor is not lining up properly.

[Umai Naa!!]

When you loosened the 3 13mm bolts on each cam gear, where are the gears positioned now?

[claude626]

The black diesel is from the tandem pump, it seems its a known issue. I replaced the pump and it still will not start...

[claude626]

reading from the ODBC data I am seeing 230 rpm during cranking. this is without external assistance to the battery.

Is the 280rpm threshold value an absolute?

[Umai Naa!!]

Yeah, from my understanding it is.

[claude626]

Just tried to start it with a start trolley. RPM's not above 280rpms for more than a second or so.

Is this a sigh of a nerfed starter motor.?

Vehicle system voltage did not drop below 11.5V during cranking...

[claude626]

Just tried to start it with a start trolley. RPM's not above 280rpms for more than a second or so.

Is this a sigh of a nerfed starter motor.?

Vehicle system voltage did not drop below 11.5V during cranking...

[claude626]

Umai,

Thanks for the help bud....

[claude626]

Just to clarify the 280 rpm threshold. my Passat is the 125kW Tdi BMR engine. is this the same value regardless of the details...?

[Umai Naa!!]

It applies to all diesels from around 2005.

Have you had it scanned for codes?

These motors were known for the injectors dying. Could be totally coincidental for this to occur while you've had it apart.

If it's logging injector open circuit codes, that would be the place to start looking.