I've been having a bit of trouble for a while now with starting.
It's really intermittent, although it has become progressively more frequent.
It will happily crank over and sounds as if it's about to start then fails. This can repeat quite a few times (10+ in the worst cases) until it starts. If it's taken a few goes to get it running then you will get some white smoke from the exhaust - this is the unburnt fuel, so it is definitely injecting fuel even though it won't start...
As I said this has been going on for a while, maybe 6 months now. Initially it was a case that the problem may happen a couple of times a month and it would always start on the second attempt. More recently it's happening much more frequently, and regularly requires quite a few attempts before it will start.
I've had in on the diagnosis machine (I'm quite lucky and have free access to one). No error codes, nothing, nada. Even had the diagnosis machine on it during starting while it was having the issue and everything is as it should be (i.e fuel pressure is good, all sensors are a go). The diagnostics also confirmed that the engine is perfectly balanced when running, no misfires or anything like that.
There is not a single issue while the car is running, it's purely a starting issue. Fuel economy is as good as ever, runs perfectly and the speedo rev counter are accurate.
I've gone ahead and replaced both the camshaft and crankshaft sensors now but this hasn't helped at all and it's still happening.
I'm confident it's nothing to do with the glow plugs (it started fine mostly during the winter) and the issue happens both during hot and cold.
As in, the issue is so intermittent that it can occur after a two hour cruise on the motorway when you stop at a service station, or in the morning. It's seems unrelated to hot or cold ambient or engine temperatures and how long you've left it sitting does make a difference either. Wet or dry doesn't make a difference either.
I'm all out of ideas and can't think what else could even begin to cause the issue. It appears to be electrical, but what else is involved in the starting process that could affect it?
Any ideas / thoughts / experience of the same issue are all welcome!
Just to be clear it's a 57 plate 2.0 TDCi Focus with around 70k on the clock.