I've owned a '97 E320 since new (same 104 engine as S320).
At about 18K it began to have a delayed hot start - no start until I
stepped on the accelerator, then immediate start. At 18 K the dealer
checked the fuel system's pressure - nothing found.
The problem is worst between .5 to 3 hours after hot shut down; cold
start is fine. The owners manual even tells one to step on the throttle
if the engine doesn't fire after 4 seconds. Now, at 37K miles, it's
worse. Otherwise the engine runs PERFECTLY!
I, too, have tried fuel injector cleaners but so far there's no change.
The exhaust reeks of unburned fuel when I start the engine - hot or
cold. #6 spark plug was wet when I changed them at 30K miles.
The Bosch ME manual describes most modes of operation - except starting.
Thanks a lot.
I'm considering removing the injectors and having them tested and
ultrasonically cleaned but cleaning doesn't repair an injector that
simply leaks due to rust on its plunger. Perhaps the test will find one
or more that needs to be replaced. i.e. http://www.witchhunter.com /
Its frustrating because the engine runs very well otherwise - but when I
look at it there are various ananomous boxes attached to the intake
manifold that I know nothing about - perhaps one of them......