98 ML320 Not starting when hot
 

I have a 98 ML320 w/99K miles. After the car runs hot, in hot weather and I shut off the engine, it will not restart until the car cools down. A local MB shop cannot determine the problem. There are no codes stored. The fuel system has been checked and a new relay installed - new fuel pump at 97K.

Any suggestions?

They should attempt to duplicate the conditions in which this is happening. I would recommend having a fuel pressure gauge handy so if/when it fails they can check to see if it's still a fuel pressure problem or not, this seems most common.

Gilly

Thanks for the post. They have duplicated the conditions - running on a hot day. The fuel system seems to be working fine. They say there is "no spark" before the spark plugs, but cannot identify the culprit. I have seen other ML posts with fuel system and ignition problems. Did not know if the gremlins have been seen elsewhere...

Very old thread, but I have the same symptoms on a 2001 ML320: very balky hot starts, frequent stalls after starting hot engine. Starts cold just fine, and needs to sit for about 30 min before the problem occurs. It has been to the shop twice. First one replaced the CPS, and the second replaced the fuel filter. I had decided it will not get fixed before I go broke unless I fix it. I have checked the fuel pressure and flow. Both are fine. Plugs were replaced less than a year ago. No codes. Anyone have ideas? Many thanks!

Forgot to mention: two minutes after hot start, car runs and drives fine. Probably a good problem to have, but I would like to get it resolved. Also forgot to mention: 132,000 miles, always well-maintained.

Thanks

i have a similar problem with my ml320. sometimes it will start specially cold, runs perfectly, after a while it will not start. changed the pump..the relay. and a few other sensors and parts..waiting for the gas filetr i oredered to do a pressure test on the new pump.

I had a 2000 ML320 with the same symptoms....when hot would not restart. After if sat for 30 minutes and cooled down, would start right up. My issue was the Crankshaft Position Sensor needed replacement. Found out it is a very common problem.