C5 engine control relay chattering.

westronic · Unread post by **westronic** » 15 May 2004, 18:04

Hi, are there any clever people out there, who can diagnose the engine management on the c5 hdi.When the ignition is switched on, the engine control relay chatters for about 10 seconds,the engine will not start.I have checked feed to fuel pump and it is at approx 10volt,It should of course be 12v.fuel pump works fine when powered directly.what could be dragging supply voltage down,do these cars have any known faults with fuse box ect?[?]

AndersDK · Unread post by **AndersDK** » 16 May 2004, 06:24

Not sure - do a HDI diesel still have glow plugs ??
These could initially drag down the voltage for a short time.
It sounds to me that you could have either a weak battery, or a weak battery feed somewhere. Check any of the larger battery feed cables for possible problems. And of course all fuses are secured.

wheeler · Unread post by **wheeler** » 16 May 2004, 17:59

yes they still have glow plugs but they should only come on for a second or two unless it is very cold.which relay is clicking ? these cars dont have the regular old type double relays it is controlled by the underbonnet fusebox.first i would re-check the feed at the fuel pump with either a good battery charger on the car or with jump leads on the battery from another running car.wich pin number on the fuel pump plug are you checking ? remember the fuel gauge wiring is also on this plug.are all the connectors in the under bonnet fusebox on securely ?
check these things first & report back your findings.the high pressure side of the fuel circut must have at least 170 bar before it will even think about starting so if there is a poor feed at the fuel pump then it will never start.