We have a 1998 BMW 535i V8 with an intermittent engine cut out problem. When starting the engine (generally when it is between hot and cold) the engine will fire as normal, run for a few seconds and then cut out. Often it can take 3 or 4 restarts until the engine will run normally. Then, as at all other times, the engine runs perfectly. When the fault occurs, holding the throttle when starting will keep the engine running, but it dies as soon as the throttle is released.
Anybody got any ideas?
(We have owned the car from new, it's covered 30,000 miles and never had any previous faults or repairs)
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hmm this is prior to 1999 when BMW added steel liners rather than Nikasil: the latter wore after being attacked by combustion products from hi sulphur petrol.
BMW replace these engines FOC if it has a full BMW service history.
Your fault sounds like plugs oiling up due to bore wear: as more miles are added it will get worse..
Go to BMW garage, describe symptons and wait.. is my advice.. (it has a full BMW service history I hope.. ie. annual oil changes. If not..:-(
madf
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Not a very technical response but could this be a combination of low mileage (6000 miles/year - short runs?) and the fact that the engine hasn't reached optimum temperature when you turn off and subsequently restart.
Isn't there some mechanism that prevents the over-rich fuel mixture from damaging the cat(s) and hence is causing the cutting out?
Paul
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Sorry I can't help but I very much doubt it's "Nikasil" related - the revised 3.5 and 4.4 V8s didn't have nikasil liners, only the earlier 3.0 and 4.O had them.
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Thanks for the replies, yes I'm aware of the Nikasil issue but we were reliably informed (before we bought the car!) that all of the V8 engines in the E39 5 series have steel liners. Also the car shows absolutely no other faults or symptoms at all.
Could be to do with short runs but it has been used for several 2 hour plus motorway journeys recently, and the problem will still happen after the car has stood for half an hour to an hour (not every time though).
I'm thinking that some kind of sensor has gone out of range and this is affecting the enrichment and idle speed control, but which one....?
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There is nothing you can do on a DIY basis. Either take it to BMW or get a reliable independent suitably equipped to firstly check for stored Trouble Codes on the engine ECU then run live data checks via the serial port on the components.
Sorry
Andrew.
Simplicate and add lightness!
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Problem was a faulty camshaft sensor, identified clearly by stored faults on the ecu.
Hope this info is useful for someone in the future...
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