Bad Starting Merc

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Wed 31 Dec 2003 10:52
Bad Starting Merc - Marcos{P}
My W211 E320 CDI is struggling to start. The problem first arose about a month ago. The engine turns over for about 3 - 4 secs before it fires, normally it will fire up within 0.5 secs. After 2 weeks of this it decided not to start so had to be recovered to the dealer.
The dealer diagnosed low pressure in the common rail and changed the sensor and the rail but the problem still persisted. Eventually they tested the injectors and found one to be faulty, it was changed and the car worked perfectly.
Monday night the same problem came back with extended cranking to get it started. It was in the dealers yesterday and they can find no faults but it still wont start as quick as it used to.
I have told them that as it seems to be exactly the same symptoms as last time that it might be another injector but they say not.
I have now got the car back but am just waiting for the time when it will completely fail again.
Any ideas?
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Wed 31 Dec 2003 12:53
Bad Starting Merc - Roger Jones
I know nothing of diesels or your use of the car, but, if you can find the equivalent of the injector cleaner I use in my petrol engines in the form of a fuel additive, then try that before considering more expensive options. Poor starting was one of the persistent problems on my old Audi, which also had cool-running problems, and the VAG fuel additive/injector cleaner cured both immediately, and starting needed no more than one feather touch of the key thenceforth. If this turns out to be completely irrelevant, sorry, but it's just an attempt to help.
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Wed 31 Dec 2003 15:19
Bad Starting Merc - Marcos{P}
I have been considering this solution for a while but I thought the MB mechanics would have already thought of it.
I may give this solution a go.
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Wed 31 Dec 2003 15:42
Bad Starting Merc - Aprilia
I would have thought lack of fuel or lack of compression would be the most likely causes. I'm wondering if there is a pressure problem (i.e. wear/damaged fuel pump?).
I wouldn't think additives will help much. Your system works at a very very high pressure and I would think it is less likely to suffer from sticky deposits in the injectors than a conventional Diesel.
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Wed 31 Dec 2003 16:08
Bad Starting Merc - Marcos{P}
In March it was fitted with a new fuel pump as the old one leaked. When the mechanic first came out to it he asked if it had had the fuel pump changed as the old ones kept leaking resulting in low pressure. After the garage replaced the faulty injector a few weeks ago the problem was sorted. The same problem has come back and I have been told by an independant that he has had a few with faulty injectors with the same problem and he normally changes all the injectors if its warranty work.
The garage are adamant that it is not a faulty injector this time but I am sceptical.
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Wed 31 Dec 2003 16:43
Bad Starting Merc - autumnboy
I not sure about Merc's, but are there any Glow plugs on these which maybe duff, or a faulty circuit or as some bigger diesels have an excess fuel device of different types for starting from cold.

Autumnboy
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