Technical Starting problems 2008 3.0l X250

[John greenfield]

I have a starting problem that 3 garages have not been able to get to the botton of. When starting sometimes the engine will crank and almost start but then not catch so I keep cranking for a few more seconds. Sometimes it will then catch and run, other times I switch off and try again, sometimes with the same almost firing but not continuing to fire. It is difficult to describe but it is almost like it is trying to start only firing on maybe one cylinder. It is more of a problem when cold but equally bad if left for 3/4 hours. It sometimes even does it when warm and is just switched off for a minute or so. When it does start it is instantly running smooth on all clyinders.
There are no fault codes showing and no warning lights on the dash. The starter motor has been replaced along with cleaning up of all the starter motor cables and a new battery fitted. Injectors have been checked with a flow test and I have been told they are all ok.
Once running the motor is super smooth, loads of power and a clean exhaust.
It may or not be related but looking all around the engine bay I have found several plugs from the wiring loom just hanging loose and not connected to anything. They could be for other versions of the X250 as I understand they all use the same wiring loom as I cant see anything to plug them into within the reach of the cable.
Anyone got any ideas ???

 

[Greasytrucker]

You’re in the realms of checking rail pressures when cranking i’d have thought for a start, fuel won’t be injected until it reaches a stupidly high pressure. That’s the case with the Multijet engines anyway and appears to be quite common

 

[Greasytrucker]

Plenty of people on here that’ll know your engine very well and will give you some pointers

 

[Communicator]

I have a starting problem that 3 garages have not been able to get to the botton of. When starting sometimes the engine will crank and almost start but then not catch so I keep cranking for a few more seconds. Sometimes it will then catch and run, other times I switch off and try again, sometimes with the same almost firing but not continuing to fire. It is difficult to describe but it is almost like it is trying to start only firing on maybe one cylinder. It is more of a problem when cold but equally bad if left for 3/4 hours. It sometimes even does it when warm and is just switched off for a minute or so. When it does start it is instantly running smooth on all clyinders.
There are no fault codes showing and no warning lights on the dash. The starter motor has been replaced along with cleaning up of all the starter motor cables and a new battery fitted. Injectors have been checked with a flow test and I have been told they are all ok.
Once running the motor is super smooth, loads of power and a clean exhaust.
It may or not be related but looking all around the engine bay I have found several plugs from the wiring loom just hanging loose and not connected to anything. They could be for other versions of the X250 as I understand they all use the same wiring loom as I cant see anything to plug them into within the reach of the cable.
Anyone got any ideas ???

As @Greasytrucker has already suggested, your starting problem could be due to either measured, or actual low rail pressure at cranking speed. Others may have have alternative suggestions.

The loose connectors are usually for unfitted options. My 2006 2.8jtd has such a cable, and the colours match those for optional engine oil level sensor, which I do not have. Also cable is in the right area to reach the optional sensor location.