Engine transmission or car(!?) bad vibration at startup

[MrGreedy]

Hi forum members,

Having a slight panic with the Merc.

It's been faultless in my ownership, but this morningI started the car and there was significant side to side vibration that was shaking the car. It felt like the engine was out of balance or something similar. I stopped the car. Locked and unlocked, and tried it again, and it did the same thing. A few RPM to say, 1,000 just seemed to speed up the vibration.

Turned off again, locked the car, wiped all the windows down with a squeegie and tried again, and this time normal. Drove carefully to work. Gave it 70% beans once to about 3000rpm once warm and seemed okay. E, S and manual mode all seemed fine.

2011 E350CDI with 7G+
Gear box serviced 12 months 3k miles ago at PCS. Car on 88k miles.

At work now so haven't been able to do a code scan, but no engine warning lights on dash.

I've got engine and gearbox mounts to do at home, but I don't think it's that as on 3rd start it was symptom free.

Help! Having a slight panic here.
Injectors?

I do run half or 3/4 of a bottle of redex diesel in my 70-77 litre fill ups.

 

[TeddyRuxpin]

Could it be ye olde glow plug relay, and ir was just struggling to start, and this shaking the car (that you say needs the engine mounts doing)?

 

[MrGreedy]

Hi buddy, thanks for the glow plug suggestion. It wasn't exactly tropical this morning!

I'm not sure the mounts are totally shot, but I don't think this is mounts. This was a visible and obvious side to side shaking of the car that wasn't there last night and wasn't there on the 3rd start, but was obviously something 'wrong' on the first and second start. It did start on the button all three times, as I charged the battery up (which is less than a year old) with the CTEK a week ago. I didn't charge it because of a problem, only because it's winter and it gets hammered with heated seats, screen and demister. Car gets regular long runs and top ups with the CTEK, so I'm sure the Varta silver battery is good .

 

[TeddyRuxpin]

Clutching at straws really, but the glow plug relay/issue can make the car really stutter/struggle until it's finally 'on' and then fine when it gets warm. It can be quite violent, although I have to say that in my case, I did see the coil light on the dash flash occasionally in my peripheral vision and the problem got progressively worse until it got to the point when I wasn't sure if I was going to be able to start the car that morning (rather than it suddenly happening).

Not sure about the sideways movement thing, though, but nothing in the car moves that way so I can only imagine it's something to do with the movement of the engine shaking the car?

Anyway, if it is that, it will keep doing it while cold and then be fine when warm, so you'll soon find out! You'd probably find that it was okay when leaving work i.e. left for ~8h but struggles left overnight or longer periods.

Can't think of anything else so hopefully somebody else can offer some useful suggestions!

Just realised that my car has double the milage of yours

 

[MrGreedy]

Just found a similar sounding experience here and with some useful comments from a helpful chap

Post in thread 'W212 E350 cdi rough' W212 E350 cdi rough | Engine

 

[MrGreedy]

Quick update.

Last night after work the car started no problems. And this morning also, started with no problems.

A lunchtime code scan with iCarsoft Pro showed no fault codes, historic or current, both on OBD and the car modules that iCarsoft can interrogate.

The car is going in for a service in Jan, so I've asked the garage to do a scan with STAR, but I'm suspecting the glow plug relay module.
It appears to be the same one as mentioned in the linked post above GSE116 for the Beru item. The same across the 231 and 265bhp cars.