Poor starting

BRIDGETMTL

MEMBER
MERCEDES BENZ

1988 mercedes 190E, 2.3, 123,000 km. We have a problem in starting the car every day. You can hear everything turning but it takes at least 5-6 tries before it catches. The funny thing is that the colder it is outside, the easier it starts. When its -15c the car starts with no problems, yet at +20c its difficult. This is not a sporadic problem, but a daily occurance. Its been in the garage for a complete overhaul, & even the mechanic (who specializes in Mercedes) is stumped. Any suggestions?

1 Reply

MIKEYBDMAN

MECHANIC
623 POSTS

I know that cranking times of four seconds is normal for the CIS-E injection systems. Do not depress the accelerator pedal while cranking.
A few things to check are the Airflow Sensor Plate for binding or rest position is not correct.
One test you can perform is to check the mA at the electrohydraulic actuator while cranking the engine. If a negative current (approx -40 to 60 mA) is measured, the CIS-E control unit recognizes deceleration shutoiff. A remedy is to replace the ignition control unit.
Check to see if the correct cold start valve, spark plugs and fuel pump relay with cold start activation up to +60C is installed.
I see there is a problem with the intake valves pulling thru the seats, and jammed hydraulic compensation elements.
I assume your mechanic has tested the fuel injector valves, but make sure the fuel distributor is working normally.
There is a fuel pump check valve located external of the fuel pump that could be allowing fuel to empty and cause a long crank time.
Good luck