Brain picking time! Starting issue.

Disco 300Tdi Auto on a twin tank veg oil system.

Starts and runs fine when warm, but when cold you need to keep it cranking until you hear the note change as fuel gets to the injection pump then she starts fine, albeit with a big puff of blue/white smoke from the exhaust!

Only does this on the 1st start of the day.

I can't really define when this started, as it was a sluggish starter before until I fitted a new starter motor a couple of weeks ago.

So far i've tried pumping the manual pump on the diesel line when starting, but that was full of diesel anyway and made no difference, we've also fitted a clear piece of fuel line on the entry to and feed from the injection pump and once restarted from that work they have remained full so it gives the impression that the injector pump has fuel, but it certainly doesn't sound like it when 1st starting?

Any ideas??

As it's from cold you have problems I'd check battery and alternator operating voltages, make sure the battery is full of electrolyte and has 'power' not just volts .. BTDTGTTS

I'd also check earth mounts and Glow plugs.

Must admit the only issue I have when starting from cold (running veg oil/diesel about 50:50) are when the vehicles been stood a few weeks and battery is low ..

Is there any smoke from the exhaust during cranking? If so what colour is it?

is there a chance that one or more leak off pipes have splits in and there allowing air to get in?

Thanks for the thoughts so far all.

Earths, checked them all when having problems with the starter motor, turned out to be a fubar starter!

Battery and alternater are all OK as also checked during starting issues around starter.

No actual smoke from exhaust when cranking but when started gives a great big blast of white/blue from the pipe, It also stinks of veg oil!! (think i'm heading to the solution having talked to a mate who fits veg kits!)

Yes there is always a chance of air getting in through the leak off pipes, so i'll replace them as a precaution.

Been chatting with a mate today, and after the Disco being sat for nearly 4 hours I started it and got much of the same symptoms I get 1st thing in the morning, he reckons that my veg kit is not purging all the diesel properly?

To test this out I have driven 5 miles on dino before switching off to see if all the veg is purged?

I had simular thing running on 100% new veg abit better on 50-50 perfect on 100% bio

It appears that I have solved my problem, after my extended purge yesterday it started on 1st turn today!

All I need to do now is figure out how to increase the purge time?