Mk7 starts fine when cold but not when warm

[manmountain]

My 08 115 T350 tipper, 200000km, has been a reliable workhorse but has developed a problem over the last few weeks which has proved difficult to solve. The truck starts fine first thing but once it has run up to temperature and stop it it will not start. The engine fires but will not catch. After multiple tries it may go again but I've found it best to leave it for an hour and then try again whereby it usually starts. Once running it goes fine. A local diesel specialist had a look did a leak off test. They said the injectors were 'a bit worn' and recommended a new set (£1100) but couldn't guarantee it was the cause. They also thought the starter may have been at fault so tried it with a different starter but no difference. A mobile mechanic came out and read the codes on Sunday (there weren't any) and did an update and the learns. Fuel filter has been changed and I removed and cleaned a very oily/ carboned up map sensor but the problem remains. Very grateful for any nuggets of wisdom from anyone who has had (and hopefully solved) a similar problem

[bambi mk 1]

A new crank sensor is worth a try

[manmountain]

Thanks for that bambi, I took it out today and it was covered in filings. I have ordered one so when I've fitted it I will update.

[knobby1]

Thanks for that bambi, I took it out today and it was covered in filings. I have ordered one so when I've fitted it I will update.

If it's covered in filings, your DMF may not be long for this world.

Lord Knobrot

[manmountain]

New crank sensor fitted, problem remains. I have also replaced the SCV but to no avail. The MOT was due last week and it passed with a few bits required but the guy I take it too for MOT's had the same issue, as I knew he would, when he tried to start it after it had warmed up. A fellow mechanic was in the garage at the time and suggested wiggling the key on start-up and it fired up straight away! I have ordered a new switch and will post when it's fitted. Why it should be OK cold but not when warm is a mystery.

[knobby1]

Did you do the learns after fitting the new SCV..??

Lord Knobrot

[manmountain]

No, we did it before, do you reckon it's worth doing them again? The new ignition switch seems to have solved the problem so just thinking I'll sell it now that it's working. Thanks to those who have replied!

[knobby1]

No, we did it before, do you reckon it's worth doing them again? The new ignition switch seems to have solved the problem so just thinking I'll sell it now that it's working. Thanks to those who have replied!

No two SCV's are the same and it needs calibrating to the rest of the system.

Lord Knobrot