I own a 99 C280 Sport with 75k on it. The car will die after about 15 minutes of running. The vechicle will re-start after another 15 minutes of sitting. When the vechicle will not re-start there is not any voltage at the fuel pump, also there is not any spark. There are not any codes at this time. I am a Chrysler tech I have known that the when the cam sensor or crank sensor fails there will not be any voltage at the pump. Reading all the posts I have seen alot about this OVP relay. Will this relay cause no spark & no voltage at the fuel pump? Also where is this relay located & is there a way to diagnose if the relay is at fault.

I've seen this before on a Mercedes ML320. It turned out to be the crank sensor. It would start up and run for about fifteen minutes and shut down. the fuel pump will not run when the is no signal to the ignition.

Stan is correct ! The newer M112/113 engines have flywheel sensor problems. That sensor is behind the drivers side cylinder head.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

so to replace--
you unplug wire
unscrew with socket ?

My ML320 wont start - thought I would try the crank sensor.

__________________
Steve Danville
what i did myself.
CPS
rear shocks
MAS x 3.
SparkPlugs (twice)
Fuel pump & Filter
Window switch
replaced both failed horns with Honda horns.
Cleaned ERG Tube
Oil changes
Oil consumption Fix
Brake Pads
A/C Recharge
Anti-Freeze change X 2.
Front Shocks. Monroe. $90
Mercedes Warrenty Work:
Harmonic balancer,power steering clamp. Cat converters.Drive Shaft Bearing.s
Replaced Outer Lower Tie Rods and front lower ball joints at 156,000 miles