Hi all.
I've just experienced one of the most frightening moments of my life.
I own a 2009 XF 2.7D and it just tried to kill my Mrs and I.
I was taking her to work and we go through a little country village on the way. I turned up one of its streets and started gently accelerating between the parked cars either side when the car just went mad. There was a mechanical clunk from underneath somewhere, the engine revved to a speed I didn't think it capable of hitting and we accelerated away faster than I thought the car was capable.
Seriously, I was doing about 25mph when it happened and the rear wheels started spinning on a dry road leaving a cloud of tire smoke behind me. DSC was on so that should have been impossible.
I slammed on the brakes as hard as I could and that did reduce the acceleration somewhat but not completely. I was just reaching for the gear selector when, suddenly, it went back to normal.
I had no error messages and the only sign that anything had gone wrong was a smell of burning that I assume was from the tire smoke. The whole incident lasted about 2 seconds.
I continued on slowly with one hand on the gear selector and tried flooring it when I reached a bit of straight road. It accelerated normally at first then the same thing happened again but just for a fraction of a second this time. Stronger acceleration and over revving (I already had my foot planted so it shouldn't have been able to increase acceleration speed).

I've seen a few similar threads to this but nothing too recent and the ones I've read have had a lot of possible causes suggested. So I wonder if a definitive answer had been found since those early occurrences?

The car has only had one issue since I bought it. The alternator failed a couple of months ago and had to be replaced but apart from that she's been an awesome car. Now I'm terrified to drive her and I need to pick the Mrs up in the morning.
Wish me luck.

 

Sounds like a problem the 2.7D is prone to where regen(s) has/have failed causing excess diesel in the oil and/or a turbo fault such that the normal control system isn't in charge.

There are quite a number of these on the net with that engine if you look, sadly.

Possibly the DPF is partially blocked.

 

Hmm, I've seen a few posts that say it may be a turbo issue but I've not seen the dpf mentioned before and I'm not sure what a regen is.
All 3 options sound expensive though 😥

 

Google 'runaway diesel'. There are lots of links as to what possibly happened.

Have you checked your engine oil level to see if it is too high?

 

I assume you have checked the floor mats carefully? That has been the cause of many of these issues.
And dare I say it without someone taking offense - 90pc of the time it's your own shoe catching the edge of the accelerator and the harder you push the brake the harder it tries to accelerate...

 

Yeah, I've seen posts about that but it can't apply in this case. I wasn't braking when it happened. I was accelerating gently after turning a corner so the throttle was barely pressed.
Plus the acceleration was more than I've ever managed to get the car do before.

Oil level seems fine. I haven't lost or gained any but are there any other ways to check for runaway dieseling?