I have tried to measure the EHA with a multimeter: 1990 - 260E

With ignition on: 18,1 mA
fuel-cutoff: ca -60mA

But the values with engine idling or when I'm driving are strange.

Sometimes the values fluctates around zero, but most often the value start to count up to 12,6 mA and stops. Never above this value (exept for fast accelleration etc.). After it has reached this value, it is constant (almost).
Sometimes (but not so often as the case above), it starts count in the oposite direction down to -9,5 mA

Even if I get these values, the engine is running as normal.

The reason I tested this is because I have noticed that the engine hesitates after I have interrupted a full accelleration. Almost nothing happens when I push the throttle. If I don't interrupt the accelleration, the engine works as normal.

I hope someone out there has an answer to me.


Grunde

The EHA reading appears to be compensating for a lean condition so you may want to double check your fuel injector seals and your intake for air leaks. Also, have you installed a new O2 sensor lately? My preference is to recommend a new one every 60k, 90k tops, to maximize fuel mileage.

That push water stuff isn't so cheap anymore!

No, I have not installed new O2-sensor. But I have checked it with multimeter and gets the correct values.

Grunde

The values you are seeing are near the end of compensation especially the 12.6 number.

You should do some standardized testing. Check the numbers at various rpms and always at constant speed. If you are getting closed loop activity at around zero at some point you need to know what about the new point has changed. If you increase speed and loose control you may need to see the differential pressure. The 12.6 number has lost control. (Control is the back and forth change of the current value. If the number just keeps getting bigger or smaller it is not in control.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

With a multi meter you are capable of seeing the voltage, with a graphing meter (DSO) you may see a different picture. The frequency, seen with a graphing meter, at which it generates the AC signal displays the sensors ability to react fast enough to the changes in the exhaust stream. The amplitude, which is what you are reading when you use a multi meter, will give you a good idea of the sensors switch points and that it is working, to a point.

Try checking the O2 voltage while driving down the highway at 60mph. If it reads high >500mV constantly the senor sees the exhaust as rich, if it reads low <500mV constantly than it sees the exhaust as lean. An acceptable reading would be 200mV to 800mV sweeping, or constantly changing between these two points.

I have the same problem you do except mine is on a M102 engine. I am going to measure the duty cycle and values and see what I get.
Acceleration is not a problem but if I interrupt the acceleration and resume immediately before the rev gets down I get hesitation.