E320 CDI, 2000, W210, staring problems??

[Mercsys]

Hi All,
My 2000, E320 CDI, W210, is having staring problems, sometimes! i.e. some time it will start in a second or two as it did for years, but now it cranks for several seconds until it finally starts, occasionally until it times out, but then usually will start shortly after, occasionally it will only crank a second or two then stop cranking. The above is always using the auto start function (short flick of the key). I don't think it is the fuel system as once running it has full power. Electrically I have had to replace a crank sensor (aftermarket) recently so may be associated, the battery is showing 12.5-12.6V (with the key out).
Any ideas welcome, I'm all out myself.

 

[DrNick]

Air in fuel lines. A small leak due to perished O rings allows fuel to drain back to the tank. You then have to crank a lot to refill the fuel system.
Loads of posts about this = a search will throw up all kinds of threads on it!
Parking with the nose downhill improves matters!

 

[BlackC55]

Or an injector is "leaking off" too much.

 

[mersum1es]

As above, 95% either of the suggested issues

 

[pcthrillrider]

Or an injector is "leaking off" too much.

or bad glow plugs

 

[OneForTheRoad]

Do you get white smoke on start up ?

 

[mersum1es]

or bad glow plugs

This is inline engine, starts very well even couple of plugs duff.

 

[Mercsys]

...it has always started easily even if I forgo the heater cycle, until recently. I have checked one plug and is is showing no voltage, so this is my new investigation track. The wrinkle here, is that it is mostly difficult to start but occasionally it will simply start as it did, hot or cold doesn't apparently make any difference!

 

[pcthrillrider]

This is inline engine, starts very well even couple of plugs duff.

er no the 320cdi is a V6 engine m8

 

[alecmascot]

er no the 320cdi is a V6 engine m8

In a 2000 car it will be a I6 OM613

 

[ringway]

Even up to 2003 the later 210's had inline 6 OM613. I've had four of them.
That I6 engine carried on in to the early 211's.

 

[OneForTheRoad]

The v6 came in around 2006.

 

[Mercsys]

...update.
The weather is cooling down so it is getting very difficult to start, several cranking cycles.
There is no sign of any air bubbles in the return line, so unlikely to be bad feedline O rings.
The heaters are all showing a dead short according to my basic meter, and are not drawing any current during a heat cycle, with the engine at full operating temperature. There is voltage a the relay, so the question is how to test the heaters in situ, I don't want to disturb a working heater risking breaking them, but similarly I don't want to fry a new relay on shorted heaters. Any one able to say what the current draw should be are the run at 12V, looking at the relay feed cable it will be substantial?

 

[DrNick]

When it eventually starts, does it cough and splutter with clouds of white smoke until eventually all the cylinders settle down, or does it burst into life and act normally straight away?
Glow plugs will be the former. Something else will be the latter. Maybe you should be revisiting the crank sensor or cam sensor if there is one. These have been known to have intermittent faults (usually heat related but not guaranteed)

I'm not sure the glowplug system fires up at all if the engine is warm, but other people will know for sure. Its not that cold. Glowplugs shouldn't give such severe problems if the engine is already warm in my experience.

 

[Mercsys]

When it does start is is 100% immediately, no smoke or spluttering, also it has had a new crank sensor within a few month, so not lightly.
What are the symptoms of a bad cam sensor? I have no engine lights.

 

[DrNick]

Hmm. So on the other forum, there is a thread about a E320CDI having similar intermittent starting problems and 1 poster claims that replacing the battery in the key solved the problem. Presumably something upsetting the immobilizer. I didn't think the battery in the key was important for starting, but as it doesn't require any real effort, try the spare key. Doesn't sound very likely but hey ho!

 

[Mercsys]

...I haven't tried a spare key, but I understood that the key is powered inductively once installed, so couldn't be battery, i'll give it a try, nothing to lose. Definitely out there, not one I would have ever tried! I regularly attempt to start it with the wrong key but it is never acknowledged.
I have a cam sensor on order, based on having tried 2 off crank sensors with the same difficult starting outcome.

 

[mersum1es]

Or an injector is "leaking off" too much.

Test this ^^^^

I remember only one case where CPS has gone bad by beginning at cold engine, it usully start malfunctioning hot first

Edit: of course SDS session would tell it but trial and error is always better teacher...

 

[Mercsys]

...update, Cam Position Sensor replaced, with no change, so next is injector leak off then.

 

[a111r]

GP relay, if all the plugs aren't heating?
I've a 'known good' spare one you could borrow and buy if needed.