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EGR AND INDUCTION MANIFOLD CONTAMINATION.
The accompanying pictures show the extreme contamination that can occur in the EGR (Exhaust Gas Recirculation) and Induction manifold areas of vehicles where contamination is allowed to progressively build up. The particular vehicle concerned is a Vauxhall Vectra Diesel Engine with just over 70,000 miles on the clock which has had regular oil changes. The first indication of any problem was when the Engine Management warning light came on. The car was connected to engine diagnostic equipment which indicated 'EGR Deviation' and Air Mass Meter Fault' fault codes. As can been seen, the EGR valve was heavily coated with carbon deposits along the full length of the stem and over the whole of the valve head and seat. Provided no damage had occurred to the valve seat, then it could be cleaned. On further investigation, the Boost Pressure Sensor (incorporated in the EGR housing) was found to be completely blocked. The third picture shows a portion of the Flap Assembly, part of the Induction Manifold, which again is liberally coated with carbon deposits. Such was the severity of the build up that one of the flaps (one of four) had bent, thereby allowing too much air to flow through the Induction Manifold thus triggering the Engine Management light. The flap being bent necessitated the replacement of the whole flap assembly. Further investigation found an associated problem of excessive Vacuum Pump wear, a concern commonplace when crankcase oil runs low. The cost to replace the damaged components came to, in excess of £600.I am very happy to say the owner of this vehicle was not a customer of ours. |
