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Stop Me Before I Make It Worse: BHW Long Crank Hard Start When Warm

1604 Views 4 Replies 3 Participants Last post by  TvD
My 05 Passat TDI, 250K, suddenly developed the long crank when warm problem. No problem on cold start, but once it's up to temperature, it takes ten seconds or more to fire. It never didn't fire. It runs fine once it starts. Even after the long crank, it doesn't skip or smoke.

Replaced lift pump, fuel filter, thermo-t. No joy.
Replaced fuel lines with clear lines. Air is visible on the return side,, but only after warm up.
Replaced Tandem pump. Air is still visible, still long crank. Still no joy. No codes. All readings within normal limits.
Conclusion: air is getting in at the injectors because of heat-related expansion. Injector seals?
Am I missing something?
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I have the same symptom. After getting fuel in SC my Passat began hesitating at speed. Stopped for a Lucas upper cylinder lubricant and injector cleaner. Car had difficulty starting! Continued driving, hesitation continued but diminished over next two hours. Did not stop engine til home in Fl. No further hesitation but warm starting became evident. Car cranks for 15+ sec B4 starting. (Alternatively turning ignition off for 5+ seconds then cranking again it starts right up!). I’m inclined to think the bubbles may be the issue.
BTW I changed the fuel filter (dirty & sediment in housing)!
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