Car has 255,000 km (155,000 miles)
Problem: stalls when engine gets to op temp (80deg), can't restart until cools down below 60deg. When cold starts right up and idles smoothly. Once gets hot, idle starts surging up and down until a complete stall.
Replaced the following parts (thru-out last 2 years):
- fuel pumps, fuel accumulator, fuel regulator
- fuel injectors
- spark plugs, wires, rotor, cap, coil
- CPS sensor, temperature sensor, Oxygen sensor
- OVP, EHA
- air flow meter and fuel distributor (used parts)
First time this happened about a year ago, adjusted the mixture and that seemed to fix it but not for long. Discovered the potentiometer in the air flow meter had a bad spot (worn out) just off idle position, replaced the whole meter assembly and fuel distributor, adjusted mixture and car ran great for another 200-300 km.
Now I am back to a square one with the problem repeating itself again and again
I decided to re-check the fuel pressure and followed Mercedes procedure:
Operating pressure: 5.35 bar
Lower chamber pressure: 4.95 bar
But once re-attaching the electrical connector onto EHA the lower pressure was dropping to 4.7 bar (on hot engine), which is different from manual statement which says pressure should not change when plugging the connector.
Has somebody else experienced that? This electrical signal to EHA is coming from the Injection Computer so perhaps all my problems are coming from the computer?