W210 E320 CDI Issues

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DanMorgan

Active Member
Joined
Mar 7, 2012
Messages
738
Location
Cardiff
Car
R129 500SL, W124 300CE Twin Turbo, W210 E55 AMG, W211 E320 CDI Sport
Hi All,

I have been struggling to figure out how to fix my 320 CDi for a few months now. Basically, the symptoms are a misfire/shudder/wobble when in drive at standstill or sometimes when driving at slow speeds around 20/30 mph.

2 weeks ago, I broke down as it kept cutting out so therefore I bit the bullet and had two injectors refurbed. I thought that solved it but 2 weeks down the line and occasionally im getting the misfire again.

What are the other alternative fixes for this? I have another 320 CDi parts car as well as a star machine, so worth trying different things. Also, what tests can I run on STAR to check?

Note: Occasionally, ive been having hard starts in the morning, say about 20% of the time if this helps diagnose.

Cheers
 
Best advice is to get it to a decent independent with a star machine who can diagnose any issues before you throw any more money at it. I'm sure once it has been diagnosed you can rectify the issue and enjoy your car.
 
It was an independent who fitted the two injectors recently. I've got a spares car, so wouldn't be chucking money at it if it was a sensor or something else like that
 
I had a leaking injector (hairline crack) and the garage had a spare knocking around and said I could have it to keep me on the road. It was for a OM648 I think, looked identical but obviously not correct.

Worth checking the part numbers, can check them against your VIN
 
I had a leaking injector (hairline crack) and the garage had a spare knocking around and said I could have it to keep me on the road. It was for a OM648 I think, looked identical but obviously not correct.

Worth checking the part numbers, can check them against your VIN


Is there anyway to tell if any of them are leaking? The top of the injectors are pretty clean since I have changed #6 and #2 with no hissing noise too (#6 used to hiss a lot).
 
A leak off test should be able to tell you
 
Wasn't able to do the leak test due to non having the equipment with me, however I did the compression test and the smooth engine running. Can anyone spot anything dodgey with these results?

The car seems to be getting harder and harder to start also, which is not a good sign

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Just do a dirty leak off test... Remove the leak-off pipe from the top and run it for a few secs to see which 1 is spewing out the worst! remember that if all the injectors were original when you had the 2 replaced, that the other 4 are still old and could fail at some point in the near future.
As for the compression test, I'm not sure I understand the results as there appears to be no indication line? That and how does it even measure the pressure in each cylinder without sensor or guage?
 
Injectors are within tolerance, cannot comment on the compression
 
It was an independent who fitted the two injectors recently. I've got a spares car, so wouldn't be chucking money at it if it was a sensor or something else like that

Could it be symptomatic of a failing crankshaft sensor?

I had an intermittent camshaft sensor a couple of months ago - problems solved when I swapped it for a new one. I had previously been told that those sensors don't fail. :doh:
 
Could it be symptomatic of a failing crankshaft sensor?

I had an intermittent camshaft sensor a couple of months ago - problems solved when I swapped it for a new one. I had previously been told that those sensors don't fail. :doh:

What symptoms were you getting?
 
What symptoms were you getting?

I replaced the camshaft sensor. Symptoms were intermittent EML (which would disappear again after 3 engine restarts then not come back for a week or two). Also the engine would run rough occasionally after firing it up, for around 5 seconds.

Had the engine wobble very occasionally - usually when waiting at a junction with the shifter in D. Never when driving at any speed though.

Read p0340 from a cheap dongle and a couple of mercedes specific codes on my i980 scanner also pointing at the sensor.

It was the cutting out and the hard starts that make me think yours could be the CRANKshaft though, rather than the camshaft.
 
I replaced the camshaft sensor. Symptoms were intermittent EML (which would disappear again after 3 engine restarts then not come back for a week or two). Also the engine would run rough occasionally after firing it up, for around 5 seconds.

Had the engine wobble very occasionally - usually when waiting at a junction with the shifter in D. Never when driving at any speed though.

Read p0340 from a cheap dongle and a couple of mercedes specific codes on my i980 scanner also pointing at the sensor.

It was the cutting out and the hard starts that make me think yours could be the CRANKshaft though, rather than the camshaft.


Well Ill give it ago as I have part available to me - thanks for the input!

I just don't think its an injector at the moment because they all look so clean with no bubbles around the top. I do agree that the others will need changing eventually though
 
Well Ill give it ago as I have part available to me - thanks for the input!

I just don't think its an injector at the moment because they all look so clean with no bubbles around the top. I do agree that the others will need changing eventually though

Yea, worth a shot - especially since you have the part available. Let us know how you get on.
 
Another injector changed (3 in total) and still the problem is there, if not more frequently now! Sometimes there is a hard start but not all the time.

Any other ideas? Leak test seems fine and the top of the engine is bone dry and no hissing or steam.
 
What was the reasoning behind you changing another injector when STAR showed they were all within tolerance (leak off)?
 
What was the reasoning behind you changing another injector when STAR showed they were all within tolerance (leak off)?

Could see steam and puddle of diesel around Injector of 5 and then I did leak test (Should have mentioned)
 
I'd guess at air in the system.
Can you smell diesel, especially in the morning?
The HP diesel pumps can leak when cold, but re-seal themselves when up to temp.
Also, could be a problem with one of the three fuel pipes (one is only 0.5mm from the polybelt and does sometimes get scuffed) or a split in one of the O-rings on the pipes.
If it really struggles to start when cold, but is fine when warm, it may be air in the system, but diesel does become less fluid when the temperatures drop outside.
 
Not sure if you have already gone over this, did you swap/check the rail sensors?
 

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