muddy
07-01-2008, 02:51 PM
Having had 3 previous 2E engined Passats that never gave a moments trouble the latest one is playing up.
When the engine starts from cold, it won't hold a warm-up tickover. It sounds lumpy and dies. If you give it a tiny bit of throttle to try and hold 1,000rpm - then it hunts very regularly between 500rpm and 1250rpm. If you give it a brief rev. and then take your foot off it drops down below tickover and dies.
If you persevere and get it warmed up then you can get it to tickover at around 900rpm but it still seems slightly lumpy. When revved warm, it will drop back way below 900, 'stumble' anf then come back up to 900.
Have cleaned idle stabilisation valve with carb cleaner. No change.
Have swapped idle stabilisation valve for known good one, No change.
Are these typical symptons of a possible vacuum leak or could the throttle potentiometer be dirty or duff ? I have a spare good one to try if that seems a probable cause.
Hope someone can shed some light on this. Thanks.
When the engine starts from cold, it won't hold a warm-up tickover. It sounds lumpy and dies. If you give it a tiny bit of throttle to try and hold 1,000rpm - then it hunts very regularly between 500rpm and 1250rpm. If you give it a brief rev. and then take your foot off it drops down below tickover and dies.
If you persevere and get it warmed up then you can get it to tickover at around 900rpm but it still seems slightly lumpy. When revved warm, it will drop back way below 900, 'stumble' anf then come back up to 900.
Have cleaned idle stabilisation valve with carb cleaner. No change.
Have swapped idle stabilisation valve for known good one, No change.
Are these typical symptons of a possible vacuum leak or could the throttle potentiometer be dirty or duff ? I have a spare good one to try if that seems a probable cause.
Hope someone can shed some light on this. Thanks.