BKD Cold Start Issues

[JoshGreenUK]

Hi all,

Merry Christmas to everyone first of all!

I have a 2.0tdi BKD with an issue that drives me insane, it is quite heavily modified running 360bhp, if the car is left overnight or so cranking takes a good 15-20 seconds, sometimes 3 sets! It has always fired up eventually, when it fires you can hear bits of fuel igniting and then when it does start it is rough for around 20 seconds, there is some misfiring too.

When it’s warm, it runs brand new, lovely and responsive and no misfiring.

I have sat the car outside for 6 months as due to the times it’s not really been used at all, and I know this problem exists so I just pretend I don’t own it until I can be arsed to do something about it!

I decided to get some temp clear lines and hooked up between the lift pump and filter, and the filter and rail lines expecting to see a huge bubble indicating air getting in.... it did not turn over again this morning and there was a small bubble of air but as soon as pump primed that was gone...

What would you guys try next in diagnostics before sending it for more serious surgery lol

I have genuine VCDS too FWIW so have access to diagnostics and tools.

Many thanks
Josh

[Josho]

They suffer with injector seals but more commonly on the BKD is the tandem pump seals.

[JoshGreenUK]

It’s had its injectors out new seals and bolts out approx around 5k ago..

I would have expected to see air in the pipes ? I’ve had previous BKD which cranked and started in less time when I run out of fuel lol!

Any other thoughts at all?

EDIT: Just actually went and cranked it and it started within 5 seconds, lots of white smoke after start, smells of diesel even on idle. This was ~20 seconds after starting:



Now when warm (60ish):

Edited by JoshGreenUK on Friday 25th December 14:35

[NGRhodes]

Glowplugs would be worth investigation.
Try leaving ignition on for an extra 20s before starting after the glowplug light goes out.

[JoshGreenUK]

NGRhodes said:

Glowplugs would be worth investigation.
Try leaving ignition on for an extra 20s before starting after the glowplug light goes out.

I have tried that - no joy, no glowplug fault either and VCDS says 4.03 seconds glow plug time @ 1C outside, after 2nd glow cycle drops to 0.83s

[JoshGreenUK]

Hi all,

Replaced tandem pump and issue seems to be mostly resolved, replaced fuel housing and tipped the contents out into a cup and there is a quite a bit of oil which separated from the fuel ... is it worth looking at injector seals or could this be the pump failing?

Thanks

[vagman1979]

Did you ever get to the bottom of this, I have a similar issue, although it's not as bad as yours, it still takes me 7/8 seconds of cranking before it starts up, once it's warm it runs and starts up just fine.