Checking Throttle Synchronization

Engine Without Individual Exhaust Gas Extraction Point:

NOTE:
During routine service work, there is no need to conduct a vacuum test or exhaust synchronization test. Synchronization is only required during repair work or if a complaint has been received (e.g. rough idle).


Prerequisite - pressure rod setting okay, refer to Throttle Body/Throttle Plate/Adjustments





- Remove seal caps (1). Connect up vacuum measuring unit.
- Measure suction pipe vacuum at all 6 throttle valve spigots and note results. Leave sealing caps (1) on the throttle valve spigots which are not to be measured.





- With screw (2 socket 7 mm WAF), set each throttle valve spigot to the same vacuum level = 8.5 ± 1.5 in.Hg. (300 ± 50 mbar) at nominal idling speed.
- Fit new tamper-proof device (2) once adjustment has been successfully completed. Then check engine idle speed and CO content.

Engine With Individual Gas Extration Points:

Prerequisite - pressure rod setting okay, refer to Throttle Body/Throttle Plate/Adjustments





- Disconnect oxygen sensor plug.





- Measure and compare CO values at the extraction points.





- Check and adjust CO, if necessary, with screws (2) equally to obtain 0.8 ± 0.4 % Vol.
Max. permitted deviation between the cylinders not greater than ± 0.2 Vol. %.
- Connect up Lambda oxygen sensor plug.