Difficult starting.

simufly

A2OC Donor
United-Kingdom
Tid 75 54 plate. 50 mile commute.
Recently it takes alot of cranking to get started first start of the day Once going its fine throughout the day.
Usual Fast cranking speed with good battery. All earths checked and cleaned. Glow plugs all changed last couple of years.
No VCDS engine faults showing.
Any ideas?
I am considering water temp input or crankshaft sensor.
Would a failing (but not totally failed) crank sensor show uo on VCDS?
Thanks
 
Sounds like fuel drain back as its cranking over fine. does it then slowly start to splutter and fire up !!
 
id suggest its Glow plugs as you say it runs fine after you have got it started, and youv said it cranks over well as the ECU wont inject fuel till rpm goes over 250rpm , id also check the glow plug relay as TDI's dont like starting without preheat from the glow plugs and common fault they burn out as there not just used to pre heat they also after glow till the engine warms up a bit
 
Thanks for the input. What is it then that stops the fuel draining back, is there a NRV in the system, if so where is it?
 
Do the basics first, test resistance of the glow plugs, check fuel return lines etc etc but fuel pump seals or injector seals are a possibility. Can you smell diesel under the bonnet?
 
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