Merc ml w163 starting problem..Glow plugs??

si69b

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The last 2 mornings my ml w163 2002 model failed to start. When I turn the ignition key it turns the engine over but it doesn't start. After about 10 minutes of trying it starts. Is this a sign it needs new glow plugs???
 

Uncle Benz

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More likely to be O rings on the fuel lines in my opinion.
 
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andy@pcd-ltd

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It is a very common problem on the diesel engines
 

whitenemesis

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If it needed new glow plugs the warning light in the cluster would come back on?

That said CDI engines can easily start without glow plugs even at sub-zero temps..
 

tony jr

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Your engine will start without the glowplugs so that will not be your problem. It is more likely to be one of the following:
1) cracked o-ring seal on one of the low pressure plastic fuel pipes allowing air into the system - cost pence and easy to change (fuel lines can get brittle with age so be careful)
2) blocked fuel filter
3) one or more injector with a leaking high pressure seal giving rise to an excessive leak-off of fuel and thus preventing the rail pressure from reaching the required threshold before the engine will fire. this is worse in cold weather. This is easy to spot with a leak-off test and the injector seals can be changed in situ without having to remove them from the engine.
4) leaking seals from the high pressure pump also usually common in cold weather - usually associated with leaking fuel from the pump.

I would take the covers off the engine and look for air bubbles in the plastic fuel pipes near the high pressure pump first, then possibly replace the o-rings and see if that helps. Next I would look at doing a leak off test and look at the rail pressure.
 

stumo

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yep fully agree, tony jr has given the full and final answer.

Hopefully its just the o-rings as seen by bubbles in the clear lines, they are cheap and easy to replace.

I'm interested tony, do you have a link or something for replacing the injector HP seals in-situ? I have one injector that is leaking off more than the others. I was thinking I would have to get a whole new injector, but if it can be DIY that would be awesome.
 

tony jr

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yep fully agree, tony jr has given the full and final answer.

Hopefully its just the o-rings as seen by bubbles in the clear lines, they are cheap and easy to replace.

I'm interested tony, do you have a link or something for replacing the injector HP seals in-situ? I have one injector that is leaking off more than the others. I was thinking I would have to get a whole new injector, but if it can be DIY that would be awesome.


I have two injectoirs with excessive leak-off. I rang around a few garages and they said I needed to replace the injectors. I was loathed to do this because of the problems I had had previously experienced trying to remove a stuck injector that took over 10 hours so a spoke to diesel specialist on another forum who told me that on commercial engines diesel fitters often just replace the seals with the injectors still in the engine. I spoke to a local injector specialist and he said he does this alot and he did both of mine in an hour and half and charged me £100 + vat - the engine fired first turn of the key!
 

Steve@Avantgarde

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I have two injectoirs with excessive leak-off. I rang around a few garages and they said I needed to replace the injectors. I was loathed to do this because of the problems I had had previously experienced trying to remove a stuck injector that took over 10 hours so a spoke to diesel specialist on another forum who told me that on commercial engines diesel fitters often just replace the seals with the injectors still in the engine. I spoke to a local injector specialist and he said he does this alot and he did both of mine in an hour and half and charged me £100 + vat - the engine fired first turn of the key!

How does that stop the copper seal at injector face leaking though? People struggle to remove injectors because they dont have the correct tools/knowledge. I have never failed to remove an injector from any engine under any circumstances.
 

stumo

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No no no this is the Diesel leak-off Steve, not black death style leaking. These seals must be inside the top of the injector, not the copper injector combustion seal down the hole.

Its interesting, I will ask around locally about doing it in situ. That would save quite a lot of hassle, although I wonder how they can ever properly test the injector afterwards. I guess you only find out sometime later when you get a hole in the piston? I know here you have to send your injector in to get it rebuilt and then tested. Its cheaper than buying new, but not by much.

EDIT: we should add an item 1.5) to tonys list....
1.5) The pressure regulator valve at the back of the fuel rail.
 
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rjevon

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I have two injectoirs with excessive leak-off. I rang around a few garages and they said I needed to replace the injectors. I was loathed to do this because of the problems I had had previously experienced trying to remove a stuck injector that took over 10 hours so a spoke to diesel specialist on another forum who told me that on commercial engines diesel fitters often just replace the seals with the injectors still in the engine. I spoke to a local injector specialist and he said he does this alot and he did both of mine in an hour and half and charged me £100 + vat - the engine fired first turn of the key!



tony_jr,

Who did this for you as I need a couple doing and not far from Nottinghamshire ?

Richard
 

tony jr

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How does that stop the copper seal at injector face leaking though? People struggle to remove injectors because they dont have the correct tools/knowledge. I have never failed to remove an injector from any engine under any circumstances.

I agree with you that you can always remove an injector the problem is how long and hence how much is it going to cost! I had my fingers burnt a few years ago by a main dealer who replaced the copper seal on a leaking injector for me and charged £1.05 for parts (new seal and stretch bolt) and then 7 hours of labour to remove the injector! Others have taken as little as 30 minutes to remove and re-seat - you just dont know until you start.
 

Steve@Avantgarde

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I know what you were talking about with the high leak off......

Point is, high leak off or not, the injector is stuck for a reason, probably the black death has already started and not worked its way up to the rocker cover yet.

So even though someone has replaced the seals in situ, its still only half a job in my opinion as not resealing them is just another issue to fix when they are even more gummed up.

If you remove them with a hot engine using the correct puller/slide hammer, even the most stubborn ones will come out, in less than 7 hours too!!
 
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tony jr

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I know what you were talking about with the high leak off......

Point is, high leak off or not, the injector is stuck for a reason, probably the black death has already started and not worked its way up to the rocker cover yet.

So even though someone has replaced the seals in situ, its still only half a job in my opinion as not resealing them is just another issue to fix when they are even more gummed up.

If you remove them with a hot engine using the correct puller/slide hammer, even the most stubborn ones will come out, in less than 7 hours too!!

HI Steve, my injectors were not leaking and causing black death I just had excessive leak off due to cracks in the high pressure seals. I decided to just have the high pressure seals replaced in situ that way I would not have to have the injectors removed and reseated and risk potentially large labour costs based on my past experiences. The job was done quickly and very professionally - you could see the crack in the old high pressure seal. Several months on the injectors are still not leaking and no sign of black death - I check under the cover every month. In this case the injectors probably would have easily come out but without trying I don't know! The only point I was trying to make is that it is possible to change the high pressure seals with the injector still in the engine. This is no good if you already have an injector that is leaking and in the process of black death - here the only choice is to remove, reseat and replace the copper seals. Hope this makes sense! Pity you are so far away not all mechanics find it easy to remove injectors.
 
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si69b

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The last 2 mornings my ml w163 2002 model failed to start. When I turn the ignition key it turns the engine over but it doesn't start. After about 10 minutes of trying it starts. Is this a sign it needs new glow plugs???

Just an update....My mechanic changed all filters and now I have a 1st time starter again
 

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