Black Box on Side of Fuel Distributor

[santora4]

Greetings All - This is for a Mercedes 560sl.

Could someone let me know what the little black box on the side of the fuel distributor is used for? Gasoline flows through this little unit.

Also, what happens when it is disconnected for long periods of time?

I am experiencing bogging and when I disconnect this the engine runs perfectly. Could it be that the unit is not bad but something else is sending this the incorrect message or does this unit run alone.


Thanks
1987 560sl

[sbourg]

It sounds like you are referring to the 'electro-hydraulic pressure actuator', if yours is a KE system. This is the output device of the ECU for closed-loop lambda control. Disconnecting it leaves you running in the default mechanical injection mode, which should be pretty close. I would guess your primary ECU input device for closed-loop mode has a problem. Check the O2 sensor first.

Steve

[santora4]

Problem resolved -

As usual the O2 sensor was fouled thus sending an incorrect signal to the EHA unit.

Replaced the O2 unit with a universal O2 sensor and the car runs like a charm. Smooth.

Thanks for your help