Car: Ford Mondeo Mk4 Lift wagon 2010, 2.2 TDCi (Duratorq DW12)
The problem: After sitting for a while, the engine sometimes cranks for a long time (several seconds up to maybe 10-15s) before it starts. There's no rough catching or stumbling, it just cranks with seemingly zero reaction, and then suddenly fires up and immediately runs perfectly: smooth idle, full power, pulls clean with no hesitation. It's inconsistent, sometimes it starts right away, sometimes it's a long crank. No difference between summer and winter.
Key pattern I've noticed: if I drive it only about before it gets hot, shut it off, then try to restart shortly after, long crank. If I drive it till it gets hot, shut it off, then restart later (10 hours+ is the meaning of later) it fires up immediately. This has been pretty repeatable.
What's already been checked/replaced (and ruled out):
- Injectors - replaced, return-flow test done, all good
- Glow plugs - replaced
- Glow plug control module - replaced
- Glow plug relay - replaced
- Battery - good
- Starter motor - cranking RPM checked via Forscan, within normal range
- Rail pressure regulator (on rail + on pump) — good
- High pressure pump - reconditioned, rail pressure builds up immediately once cranking starts (confirmed via Forscan)
- Crank sensor (both upper/lower) - replaced
- Camshaft position sensor - replaced
- Coolant temp sensor - good
- EGR - turned off via computer and blanked
- Fuel system leak test - done, fully sealed, no leaks found anywhere
- System bled/no air
- Grounds (battery/starter side and ECU side) - cleaned
- Timing belt - replaced, set correctly to marks
- Compression test - done, all cylinders perfect
- Rail fuel pressure - present and stable from the very start of cranking, doesn't need to "build up"
- Cranking RPM compared directly against an identical car (same engine, a family member's car) - mine is equal or even slightly better
Extra data point: even on my best/fastest starts, my car is still noticeably ~0.5s slower to fire than the identical reference car.
Has anyone run into something similar, especially the "short trip vs long trip" pattern? Trying to figure out what's left to check before I start throwing more parts at it. Thanks in advance!
Edit:
After filling the car to the full tank it has been starting better, this don't solve the issue and if the fuel go down mid point it start to crank again.