2008 2.4 cold start problem solved
Just putting this up for any one else with this problem.
I have owned my car for two months and has always had cold start issues, it would start but would take about 5 to 10 seconds.
After reading many posts I thought I would try the glow plugs first as my car is the later engine with the longer glow plugs and it's possible someone had fitted the wrong plugs in it 120k lifetime.
Well i removed the old plugs yesterday (get the engine hot first) and low and behold 5 incorrect and short NGK plugs were fitted. I tested them and they were all good at under 1.5 ohms. I replaced the plugs with the recommended BERU GN069 from Mr auto......... And today the coldest day of the year so far it started instantly with no noticeable smoke😎
It still needs the software update as it's lumpy for a few seconds and requires me to hold the revs at 1k for 5 seconds or so.
One other issue I found was one of my diesel return pipes (top of injector) was leaking slightly and according to my uncle would account for the longer than normal starting over the last few days. I changed one section then started the car to find another section was leaking! So I replaced them all (about 18") for a few pound from the auto shop for peace of mind as they had all become hard.
I believe the plugs were the issue and the leaking pipe has only just happened, please note my car has a egr blanking plate and new manifold with flaps connected and working and it still started like junk.
I hope this helps others with the quest to solve starting issues on a 2008+ 2.4 jtdm.