We have an ongoing hot starting problem. The cold or morning start is usually no problem. After the car has been driven around town or out on the highway, then we stop and have it sit for 30-45 minutes or longer it will start up and then immediately die. It then takes 2-5 long cranks (15 seconds), before it will start back up.

It is a ML270 CDi with 173K kms on the clock. This is what we have attempted to fix the problem without success:

-Having read several similar posts, I went and had the Crank Position
-Sensor replaced, but the problem persists.
-In the past 9 months we had all five injectors replaced.
-We have had fuel pump repaired. An indy mechanics says the fuel is returning to the engine fine, but this was during the morning when the problem could not be reproduced.
-The battery has tested fine.
-I have reprogrammed the key fobs (both).
It does not throw any codes.

Sorry if some of the explanations are off, I am a complete novice with engine issues. Any suggestions from you knowledgable Merc folks out there?

Thanks.

 

...and we are going on a long cross country road trip in this car and wanted to know if this would be risk on that journey or just an annoyance when starting..

 

Hi just wondering did you manage to find out what was causing this & what you did to retify. We are currently having the same issue with our ML270 & at our wits end after spending hundreds to hopefully fix the problems. Thanks

 

Did you pull any error codes? This should give you a great place to start before you start spending money on parts.

 

Also have the same hot start problem the car starts fine after it has cooled down. I seems that the problem is worse on a warm day.