2009 E320 W211 CDI Long Crank

[willdudeuk]

Hi having an issue where the car is taking a few attempts to start after not being used for a while.

I’ve had a search and found one similar post which mentions it could be the glow plug relay.

https://forums.mercedesclub.org.uk/index.php?threads/w211-cranks-over-longer-than-usual.135082/

I believe I have an OM642 Engine. But as I am new to Mercedes I’m not sure where I can confirm.

Also need advice on what diagnostic I can use as really need to perform a scan to see what codes it has.

Any advice would be appreciated.

Thanks

 

[M80]

V5 - Engine number P.5:, 1st 3 digits detail the engine type.
If it's post 2005 it will be the 642.

iCarsoft V2, or better the Pro, are considered reasonable diagnostics. Personally I think they are limited but do have purpose.
Do some research of posts here of where to buy from are there are fakes about.

A simple multi meter can diagnose glow plug issues, if you know what you're looking for.
Replacing glow plugs can have issues, the relay less so. Both need to be matched to each other. Wrong plugs for relay can blow the relay.

If higher mileage you may be looking at excessive leak off from injectors causing a lazy start.
Diagnosing that could be carried out with the Torque app onto an Android device, and a plug in EML327 (cost about £5). Watching the fuel rail pressures during the crank might be a give away to that.

 

[willdudeuk]

It’s low mileage. About 55,000-60,000 miles. Believe it is a 2009 model year.

Let me know if you need any more specific info?

I’ve have a look at the coils and see what I can find. What voltage should go to them and what resistance should they be?

 

[Wighty]

It’s low mileage. About 55,000-60,000 miles. Believe it is a 2009 model year.

Let me know if you need any more specific info?

I’ve have a look at the coils and see what I can find. What voltage should go to them and what resistance should they be?

There is info on YouTube for checking resistance of the glow plugs , but if they are original it’s probably worth changing along with the relay .
Also what date is your battery , it’s stamped on the terminal usually.
This cold weather loves to highlight faults .

 

[Wighty]

This was my glow plug thread

Changed my E320cdi Glow Plugs

Got my new Beru glow plugs (£50ish ) , I had an MB Beru gp already as a spare in the garage . Got the engine hot by a 45min drive , loosened the air boxes either side . Removed the turbo inlet "batwing" . Popped off the 6 electrical connections for the gp's and squirted some release fluid into...

forums.mercedesclub.org.uk

 

[M80]

There are 2 different voltages I believe, 4.4v and 7v.
The relays can start higher voltage and drop during running.

At initial turn of key you should be able to test for voltage at each plug, but it isn't there for long.

If you're seeing a continuity of around 0.4 - 0.8 ohms I suggest they're good. that's what I'm seeing on my removed 4.4v plugs.

At that mileage I wouldn't expect excessive leak off from the injectors.

 

[willdudeuk]

This was my glow plug thread

Changed my E320cdi Glow Plugs

Got my new Beru glow plugs (£50ish ) , I had an MB Beru gp already as a spare in the garage . Got the engine hot by a 45min drive , loosened the air boxes either side . Removed the turbo inlet "batwing" . Popped off the 6 electrical connections for the gp's and squirted some release fluid into...

forums.mercedesclub.org.uk

Thanks @Wighty some great info on here about the removal process which I know could be risky!!

I’ll get a a diagnostic / obd scan done and see what faults I’ve got.

Then test voltage using multimeter. Unsure whether I have 4.4V or 7.0V variant of glow plugs. Guess I’ll find out…. @M80

Would the resistance / continuity be the same at 0.4-0.8 for both the different voltage types?

If the glow plugs are bad can that fry the relay?

Hopefully the scan can narrow everything down a bit more (or perhaps confuse me!).

Thank you

 

[alexanderfoti]

As a test, next time, turn the key to position 2 and leave it there for 6-7 seconds. Then start.

If its much easier, then likely glow plug or module, proceed as above with testing each plug.

Yes bad plugs can blow the fusible links in the module sometimes. I have had some models just fail to power the plugs (and give no codes!)

 

[Mr Greedy]

Also what date is your battery , it’s stamped on the terminal usually.
This cold weather loves to highlight faults .

This.
Start with the simple stuff.

 

[willdudeuk]

This.
Start with the simple stuff.

@Wighty and @Mr Greedy I’ll check and see what battery I have (and the date stamp) and post back.

 

[willdudeuk]

As a test, next time, turn the key to position 2 and leave it there for 6-7 seconds. Then start.

If its much easier, then likely glow plug or module, proceed as above with testing each plug.

Yes bad plugs can blow the fusible links in the module sometimes. I have had some models just fail to power the plugs (and give no codes!)

Yes I’ve been doing this. But it takes several attempts before it actually starts. I will have a go again today and see what happens.

I did have the battery off and got it “health checked”. Came out ok but looks like it’s lost some of its cranking power.

 

[willdudeuk]

Couldn’t find a date on the terminals. But in the reverse it has recharge date of 09.2017 so perhaps the battery is knackered? Seeing as it’s 2022 now so 5 years passed recharge.

 

[Mr Greedy]

If it WERE the battery and you are intending to keep the car, it's not too expensive to get a replacement.
Assuming 019AGM battery like the one you photoed is the correct size, there are a good few to choose from:

019 AGM Car Batteries

We sell 019 AGM Car Batteries at the cheapest prices anywhere. Our 019 AGM Car battery is an extremely high quality product at a budget price. With a price beat guarantee you can be certain of the best deal in the UK.

www.tayna.co.uk

5 years isn't amazing for car battery life, but also the manufacturers give warranties of varying lengths up to 5 years I'm very sure for a reason (i.e. beyond 5 years it's luck of the draw). So in my view, as a relatively inexpensive DIY parts roulette for something you have had 'normal' usage life from isn't that bad.
Might be worth giving the battery a good overnight charge and recondition with e.g. a CTEK charger, and if the car fires up straight away as good as gold just after charging, it's indicating either the battery loosing condition quickly or a charging inadequacy (not necessarily just the charging equipment, but maybe not enough long trips recently to ensure full charge is reached).

The Varta Silver are well regarded on here.
You could even be cheeky, and give a couple of Merc dealers a call, say the Varta equivalents is £158 delivered from Tayna batteries (with 5 year warranty), so if they can get very close to that, you'll buy it from Merc. (buying from Merc makes sure you have the exact correct part this way because they can check against your VIN).
I've done it before and ended up with the Merc battery for around £150 a few years ago. Prices of batteries seem to go up and down like a yoyo, and prices seem fairly reasonable at the moment compared with highs over the past few years.

Might of course not even be the battery. Just helping with ideas buddy.

 

[willdudeuk]

Thanks for the reply. Well I tried starting it this morning but didn’t want to start at all.

Even with my car jump starting it with good quality cables it didn’t want to start.

So I am suspecting it’s glow plug or fuel related.

We did try a trickle charge with the battery but the cold weather has not helped!

It can start but the cold weather has made it almost impossible to start.

Still need to do a fault code scan and get the multimeter out to check the glow plug condition etc…

How much would a dealer charge to do a fault code scan? Or an Independent for that matter also? Just want a ball park so I’m not getting mugged off. Was thinking around £50 for just a scan?

 

[willdudeuk]

Can anyone confirm what battery I should have if the above is not the OEM battery? Thanks.

 

[Wighty]

Thanks for the reply. Well I tried starting it this morning but didn’t want to start at all.

Even with my car jump starting it with good quality cables it didn’t want to start.

So I am suspecting it’s glow plug or fuel related.

We did try a trickle charge with the battery but the cold weather has not helped!

It can start but the cold weather has made it almost impossible to start.

Still need to do a fault code scan and get the multimeter out to check the glow plug condition etc…

How much would a dealer charge to do a fault code scan? Or an Independent for that matter also? Just want a ball park so I’m not getting mugged off. Was thinking around £50 for just a scan?

Probably £100+ ? For a main dealer scan . It’s always tough to weigh up when it’s worth paying that kind of money for a scan .
Probably better to buy an icarsoft scanner for the future , but as we (you) stand at the moment , you need a new battery , it’s probably no coincidence that it failed on the first frost .
I would buy a new battery , then see if it starts , if it doesn’t you probably then maybe you need new plugs and a relay . If you are going to keep the car long term these are just something that need doing anyway .

 

[Wighty]

Can anyone confirm what battery I should have if the above is not the OEM battery? Thanks.

it’s an AGM battery pictured in my E320cdi

 

[M80]

We don't know how it failed to start this morning.

Was it turning over as fast as expected, or slow and lazy?
Was the donor allowed time to pass some energy into the battery, if it even needed it?

I would still want to eliminate low fuel pressure while cranking.
Excessive leak off is possible, but so is air ingress (and I realise this is post 'o' ring period).
Might even be the fuel pump.

But really this needs diagnostics to stop (or at least reduce) the guessing.

A VIN decode may well detail the battery fitted at new.

 

[willdudeuk]

We don't know how it failed to start this morning.

Was it turning over as fast as expected, or slow and lazy?
Was the donor allowed time to pass some energy into the battery, if it even needed it?

I would still want to eliminate low fuel pressure while cranking.
Excessive leak off is possible, but so is air ingress (and I realise this is post 'o' ring period).
Might even be the fuel pump.

But really this needs diagnostics to stop (or at least reduce) the guessing.

A VIN decode may well detail the battery fitted at new.

Yes was turning over fast (with donor vehicle). Without it is slower / sluggish / lazy in comparison.

I gave it a few minutes to impart some charge into the battery.

What do you mean post o ring period? Is there a known issue with injector seals or something else? Allowing unmetered air to enter the combustion chamber (passed the injector?).

But yes I agree I need a diagnostic scan as it’s just guesswork and not the correct way to fault find.

I may fork out for another tool unless there are any members near the RG8 postcode?

I’ll get the VIN over to someone if they can decode it for me or let me know how?

Do Mercedes have an online tool (similar to
VW’s ERWIN / ELSA) which allows you to pay by the hour for access to dealer information etc…??

 

[Doug1234]

Here below , same om642 engine albeit with less air filter setup and in a Jeep .. How to test relay and glow plugs.. On the Jeep the glow relay is earthed via a connection at fuel filter mounting bracket .