torque2me Posted March 5 Share Posted March 5 Hello everyone, I have own this Mercedes V-Class W638 for some time; but, in recent months, it has been experiencing sporadic starting issues that no garage has been able to solve. Commence in the mornings It never fails me; nevertheless, after a brief drive and subsequent parking for a while, when I return to start it again... It turns over but fails to start. If I wait around thirty minutes and attempt again, it starts immediately. I have replaced the O-rings on the fuel pressure regulator. The crankshaft position sensor Fuel filtration device O-rings on high-pressure gasoline pump I replaced the injectors and cam sensor a few years ago, so I doubt the cam sensor could have malfunctioned that soon. Has anybody else encountered this issue? I would appreciate any guidance you could provide. Thank you Quote Link to comment Share on other sites More sharing options...
trikey Posted March 5 Share Posted March 5 Cutoff relay, engine management relay? Quote Link to comment Share on other sites More sharing options...
stevenkeyte Posted March 5 Share Posted March 5 Failure of the Crankshaft Position Sensor may manifest these symptoms. Quote Link to comment Share on other sites More sharing options...
paulh2602601 Posted March 5 Share Posted March 5 The thought occurred to me when I perused the first post here. Approximately 34 to 35 years ago, I purchased a one-year-old Vauxhall sports vehicle. Initially, it operated exceptionally; but, after a year, attempts to start the vehicle from a heated engine sometimes yielded no results, if I recall correctly. No auditory response when turning the key. If I recall correctly, it was one of those relays. I was fortunate to visit the main dealer, where I described the issue. The receptionist suggested I try a relay switch, a little rectangular item, and provided one for testing, allowing me to return it if ineffective. It resolved the problem. Modify - my vehicle was petrol-powered with electronic fuel injection. Quote Link to comment Share on other sites More sharing options...
markjay Posted March 5 Share Posted March 5 I experienced same / same with a BMW 1.8i. If I continued trying, but may be for 1/2 hour, it would certainly catch. Quote Link to comment Share on other sites More sharing options...
torque2me Posted March 5 Author Share Posted March 5 Does the W638 diesel possess that relay? Quote Link to comment Share on other sites More sharing options...
torque2me Posted March 5 Author Share Posted March 5 I modified it, nevertheless the issue persists. This problem occurs only during short journeys, never while the vehicle is at full temperature, nor during the first cold start; it only arises after a brief excursion followed by a period of parking. Quote Link to comment Share on other sites More sharing options...
markjay Posted March 5 Share Posted March 5 I am uncertain, but it must be terminated in some manner. Quote Link to comment Share on other sites More sharing options...
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