Hello! Everyone. I got a 1991 Mercedes 190e 2.3L, which has a hard start problem when the engine is warm.

Cold start is ok, take about 4 cranks on the starter to start the car. After shut off and start immediately. It can start right away. But when park the car about 2 hours, then feel hard start the car (take about 8 to 10 cranks).

I already put new Bosch injectors, new bosch accumlator, new Bosch fuel pressure regaulator, hengst fuel filter, new battery and new Bosch oxygen sensor. Still the same problem.

Also, put 3 different used ovp relays and used CIS water sensor ( from my past parts car) . Still same problem.

Anyone has an ideas what problem.