Thursday, 24 September 2015

Lack of power in Opel 1.9 CDTi 16V engines

This bulletin investigates a common fault relating to a loss of power that affects the Opel 1.9CDTi 16V engines fitted in Astra-H, Vectra-C and Zafira-B’s.

This fault occurs mainly at medium to high engine speeds and can trigger fault codes; P1109, P1125, P1901, P2075 and P2279.


Lack of power in Opel 1.9 CDTi 16V engines
Firstly check that no fault codes are recorded that indicate an ‘intake air leak’ and secondly check that the exhaust is clear of excessive black smoke, this is to eliminate the possibility of a restricted EGR valve, another common problem with these engines. Thirdly, it is advisable to check the condition of the pressure and vacuum hoses as these are known to collapse and deteriorate with excessive heat. 

If the previous checks have proved inconclusive and/or there is no black smoke from the exhaust, it is advisable to inspect the intake manifold variable switching system.

This system also suffers from an accumulation of excessive carbon deposits from the EGR valves exhaust gases which subsequently build up and obstruct the variable intake swirl valves.  In this case fault codes P1901, P2075 and/or P2279 may be recorded. 

Follow this procedure:
Lack of power in Opel 1.9 CDTi 16V engines

Check the condition of each variable intake swirl valve actuating rod/pivot mechanism.

It is essential to check this mechanism as the bushes are plastic and way be badly worn affecting the correct operation of the system. The swirl valve mechanism is driven by a motor situated directly on cylinder number three inlet port swirl valve unit.
If this is satisfactory then disconnect the actuating rod from the electric motor and manually move the rod (1) through its natural operating range and ensure that the rod/valve mechanism is not restricted or too loose, it should move without too much resistance.

Lack of power in Opel 1.9 CDTi 16V engines

Finally inspect each swirl valve for axial play/movement.  If the vehicle has been driven for a prolonged period with this fault the insecure swirl valves subsequently cause wear to the intake manifold itself.

Replace the intake manifold and depending on its condition, it is also recommended that the drive motor for the variable intake swirl valves is also replaced.

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