ML 270 intermittent starting issues

Lazmo

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ML 270
Hi all,
About 2 years ago my 02 ML270 (89k miles ) would occasionally refuse to start in the morning. Local garage diagnosed a flat battery so I had a new one fitted. The problem persisted so I had new glo plugs fitted.
This was in the cold weather and I thought that may be an issue: waxing diesel, so I put Millers in; no change. But once started in the morning it always starts for rest of day.
2 weeks ago it wouldn't start and the servo wasn't working. I figured the vacuum pipe was cracked ect. It started OK day after so I took it in to garage. They cleaned the ERG and fitted new pipe to servo and did other checks on glo plugs ect.
Started fine for 2 weeks then yesterday failed again, but today started first time.
I see other CDI 270 owners have had similar problems. Could a knowledgable member please advise me on what to tell the garage to look for?
My nearest indie Merc dealer is in Grimsby but I'd rather stay local.
 

M80

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2014 639 Viano- 651, 5sp Auto. 2009 S211- 646, 5sp Auto.
Replace the fuel line 'o' rings. It being a cheap fix is a good starting point.
Genuine Mercedes-Benz OM611 612 613 Fuel pipe line Seal O-Ring 6019970645 X6 | eBay
see how it starts after that.
The trouble is that air passing the 'o' rings is usually over a cold night. With temperatures on the increase your issue might self solve.

Maybe follow that with an injector leak off test, again not an expensive test.
 

mersum1es

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Usually problem in rail pressure. You can see failure of o-rings as air bubbles in 'clear' lines. Second popular place is too heavy injector tank leak like said above.
 
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Lazmo

Lazmo

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Hi all,
About 2 years ago my 02 ML270 (89k miles ) would occasionally refuse to start in the morning. Local garage diagnosed a flat battery so I had a new one fitted. The problem persisted so I had new glo plugs fitted.
This was in the cold weather and I thought that may be an issue: waxing diesel, so I put Millers in; no change. But once started in the morning it always starts for rest of day.
2 weeks ago it wouldn't start and the servo wasn't working. I figured the vacuum pipe was cracked ect. It started OK day after so I took it in to garage. They cleaned the ERG and fitted new pipe to servo and did other checks on glo plugs ect.
Started fine for 2 weeks then yesterday failed again, but today started first time.
I see other CDI 270 owners have had similar problems. Could a knowledgable member please advise me on what to tell the garage to look for?
My nearest indie Merc dealer is in Grimsby but I'd rather stay local.
Replace the fuel line 'o' rings. It being a cheap fix is a good starting point.
Genuine Mercedes-Benz OM611 612 613 Fuel pipe line Seal O-Ring 6019970645 X6 | eBay
see how it starts after that.
The trouble is that air passing the 'o' rings is usually over a cold night. With temperatures on the increase your issue might self solve.

Maybe follow that with an injector leak off test, again not an expensive test.
 
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Lazmo

Lazmo

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Thank you v.much M80 & Mersum. I've ordered the 'o' rings off eBay following your link. My ML is booked in with my usual garage next week.
The really odd thing about this is: it will not start one day, even when T is 13 deg. I leave it on charge until next day and it starts first time! I dunno.
I've previously thought that a cold night: < 5 deg is always a failed start day, so I started keeping it in my garage but it still fails to start. I run a fan heater in the engine compt. for a hour then it starts, sometimes.
I'll keep you posted if the 'o' ring fix works.
p.s. sorry about the above false posts, I didn't understand how to work this board :0
 

M80

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It sounds like your asking your garage to replace the 'o' rings. I would ask them to do the leak off test while they have it.

You really could do with your codes being read when the poor starting is happening. But low pressure in the fuel rail could be down to a few causes and it's likely you would be seeing that.
 
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Lazmo

Lazmo

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Thanks for your input M80. I'll email your thoughts to the garage. The proprietor, Michael, knows his stuff but is not a Merc expert.
It started fine today; seems it has to stand for 2-3 days before the non-starting appears.
I'll let you know what happens after they've done the job.
 

mersum1es

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Ephasize that leak off test should be done engine outside temperatue, not overnight inside garage.

At home you may also try heat injectors by heat gun, then heat HP pump. Usually pump leaks out so it is pretty easy to find out.

BTW did you see bubbles running in lines?
 
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Lazmo

Lazmo

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Many thanks to M80 and Mersum. My Merc has now been fixed.

I followed your advice and asked for a leak off test, here's the work they did:

"Carry out injector leak off test, identified faulty injector no.2 and replaced with new and coded into ECU. Customer supplied fuel pump seals fitted, system bled, started and run up OK."

The ML runs much better now and the fuel economy gauge is climbing up to 29+.

It cost £370 all in but worth it. I probably keep the old bird another year, or 2.


I couldn't see any bubbles running in the lines as they all seem to be in black plastic.


Thanks, Larry :)
 

M80

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On a gentle good run you can see close to 42 mpg on these, especially in Lincolnshire, when you find straight roads.
It was a Gr Cherokee, but same engine and auto box, I did this with a small trailer. Carrying wheels to B'ham for refurb, then on to Gloucester for hang gliding kit, then home.
Fill to fill calculated, 283 miles, 41.22 mpg. Not seen it since though.
 
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