View Full Version : synchronisation of banks of M70 engine cylinders

07-20-2009, 11:11 PM
The following information is important when replacing MOTRONIC control units or EML units. Same has to be done when the battery was disconnected and this procedure also often cures rough idle.

Each control unit is programmed with certain basic values, which are only mean values.
A control unit receives various input values depending on engine load conditions and compares them with the stored values.
An adaptive system compares the input values with stored curve family values, after which corresponding orders are put out to the concerned control elements.

If, for example the EML unit were without current for a long period of time (more than 1 hour), its adaptive system would lose the stored values.

The adaptive system would have to read in and store the input values of a certain engine after restoring operation of an erased control unit or installing a new control unit.

This procedure could lead to erratic idling of the engine after starting and disturbances in overrun.

Consequently there must be conformance with the following procedures before an EML control unit is replaced or after restoring operation of a disconnected control unit.

-run engine to operating temperature.
Install (new) control unit and drive car. During test drive have the car coast three times from speeds above 5.000 RPM to the idling range in transmission range 1 (approx. 10 seconds).
-have engine run at idle speed in transmission range P or N at least 5 minutes!

These measures serve immediate and precise synchronisation of both banks of cylinders in all operating conditions.

This is important. after 5+ minutes switch engine off, take a breath and restart, your M70 V12 should now be synchronized