320ML glow plug problem

[MAXIMUS1954]

I seem to be constantly renewing glow plugs on my 2007 ML320. I have had the glow plug relay renewed but the same problem exists. When starting up I have to turn the ignition on until the glow plug light goes out then do that three or four times before the engine will fire up otherwise it struggles to start. Mercedes have said there is nothing wrong with the system but this cannot possibly be the case. Is it possible to increase the length of time the glow plug stays on or does the glow plug turn off via temperature control switch? Please could someone advise as I have renewed all 6 glow plugs now twice in 12 months.

 

[Crispian]

Did you replace them with Beru plugs?

I had the same problem on my ML,I first replaced with a set of generic none brand plugs from Germany, they each broke down within a month of each other.

Replaced the relay with a new one and a full set of Beru plugs and it's been fine ever since.

 

[andrew056]

I had a similar problem with my ML in that Europarts supplied the wrong Bosch plugs , about 6mm too short , everybody was scratching their heads at my expense as everything checked out as fine except it would only start from cold with a dose of easystart. Then somebody had the bright idea of taking a plug out and checking against a Mercedes plug . Problem solved big bill. Its been fine ever since. The only other thing could be fuel pressure , has that been checked?
Best of luck Andrew

 

[V6Matty]

you say you have to click it on an off a few times, to me that indicates the plugs are fine, but I'd wonder if you haven't got air in the lines? used to be much more common on the 270 IL5 and 320 IL6 but I'd wonder if the V6 may be the same. try starting it on the first turn after the light has gone out, if it take a good few cranks to start then it's certainly one of the first places I'd look rather then the plugs being faulty, especially as these days plugs aren't really needed for starting unless it's rather cold.

 

[Mr Filipov]

you say you have to click it on an off a few times, to me that indicates the plugs are fine, but I'd wonder if you haven't got air in the lines? used to be much more common on the 270 IL5 and 320 IL6 but I'd wonder if the V6 may be the same. try starting it on the first turn after the light has gone out, if it take a good few cranks to start then it's certainly one of the first places I'd look rather then the plugs being faulty, especially as these days plugs aren't really needed for starting unless it's rather cold.

My V6 CDI was a pig to start with a faulty relay not firing only 2 plugs out of the 6. I think it is a bit more important for them to be working. Changed the relay, never had any issues since. Before that it was judt 2 plugs which took out the relay to begin with and still had an issue. Either one goes it does not seem to like it.

 

[V6Matty]

My V6 CDI was a pig to start with a faulty relay not firing only 2 plugs out of the 6. I think it is a bit more important for them to be working. Changed the relay, never had any issues since. Before that it was judt 2 plugs which took out the relay to begin with and still had an issue. Either one goes it does not seem to like it.

but he says he's had the relay replaced as well as the plugs which would point me either to a fuelling problem, the relay faulty (again) or a HP issue

 

[andrew056]

Just had another thought are you still on the original battery it could be coming to the end and dropping voltage just when you need it most. Just a thought.

 

[Mr Filipov]

but he says he's had the relay replaced as well as the plugs which would point me either to a fuelling problem, the relay faulty (again) or a HP issue

That is a fair point

 

[tony jr]

Just a thought! Is the inlet port shut-off motor on its way out? I think it has a common power feed from then glow plug relay. It could be faulty and resulting in a surge that damaged the glow plug relay in the first place. Replacing the relay temporarily fixed the problem until the motor damaged the new relay causing the same problem!


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[MAXIMUS1954]

I seem to be constantly renewing glow plugs on my 2007 ML320. I have had the glow plug relay renewed but the same problem exists. When starting up I have to turn the ignition on until the glow plug light goes out then do that three or four times before the engine will fire up otherwise it struggles to start. Mercedes have said there is nothing wrong with the system but this cannot possibly be the case. Is it possible to increase the length of time the glow plug stays on or does the glow plug turn off via temperature control switch? Please could someone advise as I have renewed all 6 glow plugs now twice in 12 months.

Starting on the first attempt after the glow plug indicator light goes out results in the engine cranking over several times then firing with lots of white smoke issuing from the exhaust. The battery was renewed 2 months ago so no issue with that. The glow plugs and relay were all renewed by a merc dealership so they should be good also. I will get a set of Beru plugs (where can I buy those) and try again but I think V6matty may have a point if that does not work, with air in the lines. How do I check to see if the inlet port motor is at fault and where is it?

 

[hamlet1601]

Hello, maybe my problem is different, but here is the story... it might help myself as well reading your opinions.
ML270, 2001. Cold start problems. In a strange way.
Only the VERY 1ST start in the morning is dodgy. Cranks lovely, fires for 2 seconds and then cuts off. If I push a little bit the throttle pedal during the very 1st crank, it fires and it keeps it. But if I miss the 1st crank, it will never give me another chance.
I changed all glow plugs and the relay. No relief. Been told to try with the injector o-rings, what do you think?
Thanks

 

[V6Matty]

typical symptoms of air in the fuel lines, as has been suggested to you changing the O-rings should solve your problem, it's quite an easy job to do just be methodical and you will be fine.

 

[hamlet1601]

Thanks Matty. So you think it can be a DYO job? If so, is there any guidance available on the web?
Many thanks

 

[V6Matty]

I'm not aware of any guides out there but if you sign up to WIS online you can go through the pages on how to do all sorts to your car yourself.