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      01-06-2017, 02:41 PM   #52
bNks334's Avatar

Drives: '11 135i (N55)
Join Date: May 2014
Location: New York

iTrader: (1)

Originally Posted by Muppet View Post
The IM has a M3 steering pump which I think is larger than the pump in a 135i. I think that has an effect. The weight when the servotronic is working is still not light at parking speed but not unpleasantly so. With no servotronic you really have to heave on the wheel. This not helped by my car having 245 fronts and 1 degree increased castor.

I have power running to the servo valve but it is unstable and this is the problem If I add a fixed voltage, say from a 6v battery to test the valve the weight was far too light but everything worked. I get a variable voltage while the car is running from 3.7 to 5.7v with no real consistency. Very strange.

When coding I found I had to bring the car back to scratch and then add the option and then a whole of car coding. I think there are changes to other ecu's other than the JBBF.

I have tried to obtain the 1M trace files to do a comparison of the JBBF but no luck to this point. I have obtained a trace file of all the applicable codes including the servotronic codes I have found extra lines of code but have not found what ecu they are posted to.

All very strange but I do like a challenge.

By the way the addition of the rack is worthwhile. The steering is sports car accurate and fast at normal road speed.
When adding to the VO, and not being sure of what modules are changed, it's better to "process whole car" in ncsexpert. That will reset all the modules back to VO spec.

Comparing trace files won't necessarily tell you anything. The settings of "wert_1" might be exactly the same on both lines between a 135 and a 1M, but the actual data held by the value might be different.

Comparing the trace files before and after doing the "process whole car" could potentially point you to what modules are changed though... You could then do the work of researching the actual data values of the M3 and coding them to custom "wert" variables with ncsdummy.

I think you're looking at the voltage reading wrong... could the voltage be varying as the servotronic does its thing? like the voltage varies from the MAP sensor based on airflow?

A steady voltage may just be keeping the servotronic working at full tilt... which would be why the steering is "too light" when you max the voltage out.

all theory though...