Vauxhall Workshop Service and Repair Manuals

Compression (6-cylinder), Not Synchronised  

This test must be used for all vehicles fitted with the DIS ignition system, as the system does not permit a measured value to be allocated to a particular cylinder.  

Measurement:	Recording of the battery voltage variations during the start procedure.
Check Objective:	Determine the compression efficiency of the individual cylinders by measuring the difference in voltage between the compression and decompression processes.

Preparation  

Engine oil temperature 20 - 80 ° C. Switch off the engine. Switch off the ignition. Detach fuel pump relay K68.

Connections  

INPUT A	COM/TRIGGER
Connect the red measurement leads with the blue filter adapter to the battery. Ensure correct polarity!

Procedure  

Operate the starter until the message "HOLD" appears in the top right corner of the screen. The engine must not start during the test!  

Reference Curve     Notice:  If the message, "The signal was too short for an analysis." appears, the blue filter adapter must be removed and the test must be repeated.

 

Fault Diagram 1   Symptoms:   The value of the cylinder with the lowest compression efficiency is too low. The nominal value is at least 75%.   The next cylinder value has the highest compression efficiency.

Possible Causes	Countermeasures
Leaking valves or piston rings	Perform pressure loss test!

Notice: 

This compression test cannot give information regarding which cylinder is affected. This test can only be performed on vehicles with ROD ignition systems.