Lack Of Or Intermittent Acceleration / Pulsing Power

[mlkey]

Hello,

 

My first post, thought I would share this gem with you. I recently picked up a 52 plate C5 110 HDI. Shortly after purchase I started having uneven power at about 2000 rpm. Can best be described as surging. It was as if I was fluctuating the throttle, and was accompanied by a puff of smoke out of the exhaust with each surge. Sometimes I would have no boost from the turbo, other times there would be some.

 

There is every chance it is the egr valve. This can be checked very easily. Open the bonnet and on right hand drives, look on the nearside up by the bulkhead (by the brake servo), there is a small plastic shield secured by two plastic retainers. Pull the centre pin up on the retainers and pull the retainers out, remove the shield. Underneath there are 3 little round black solenoids, each with two vacuum pipes and a small two wire multiplug. On my C5, the solenoid in question has the blue electrical connector. Check which of the two pipes runs along the bulk head and down towards the exhaust manifold, and disconnect it, tape the end of the pipe up to prevent dirt entering. You now need to seal the outlet on the solenoid. Easiest way is to leave the flexible piece of pipe on the solenoid and block it with a small bolt or blanking plug.

 

DO NOT LEAVE THE VACUUM CIRCUIT OPEN - THIS COULD AFFECT BRAKING!

 

Now try your car! On mine, it was perfect, and I have gone from 44mpg and running pretty rough to 55mpg and purring.

 

Enjoy!