Bump starting a diesel

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chrisaaaaa

Active Member
Joined
Sep 11, 2013
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110
Car
C220 Est 2011 facelift
I have a manual diesel blue efficiency, this leads to stalling presumably if I do not wait long enough for the motor to get going properly before bringing the clutch up.

Sometime just dipping the clutch gets it to restart itself automatically (is there a config option to extend the time during which the car considers it a failed stop-start start?).

Sometimes I have to switch off and restart, hydraulic power steering on a stop-start car is such a good idea!

Often it feels like the car is going fast enough to bump start (> 5 mph) but it never works, that is until last night it bumped into life but sounded really rough, like not all the cylinders were firing, I switched off and restarted.

So is bump starting a no-no, do I have to condition myself to not try it?

(It is a bit strange anyway, when I was young enough to stall cars, I cannot remember it resulting in the car travelling fast enough to bump start, typically it went nowhere).
 
I would guess that bump starting your vehicle is not recommended. When using the key to start, certain 'handshakes' go on between the various ecu's and only after a green light from the ecu's is the starter motor instructed/permitted to engage, bump starting would bypass these initial handshakes and is probably why the engine ran roughly when you started the engine this way.
 
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I suspect that bumpstarting the car caused unstable running due to the cylinders having excess fuel from the previous non-firing run prior to dipping the clutch pedal.

Said that I don't think that what you are describing is right - not even for a manual stop/start car - have you had the car looked at by a garage or delear?
 
I didnt think that youre supposed to bump start cars with a catalytic converter due to unburnt mixture damaging it.(or something like that)
I have found that modern cars designed for low emissions are high geared of course and you do need to keep up the revs on take off. I also notice that modern cars dont kangaroo any more they just stall instantly. I think this has something to do with not damaging the cat as well. Im only theoretising though.
 
Something is amiss here. Every diesel I have driven can move off from standstill without touching the accelerator, even when facing uphill. Simply letting the clutch come up gently will allow the car to move off without any hint of stalling? I've only driven a courtsey car that had stop start, but sounds like yours has a fault.

Russ
 
Something is amiss here. Every diesel I have driven can move off from standstill without touching the accelerator, even when facing uphill. Simply letting the clutch come up gently will allow the car to move off without any hint of stalling? I've only driven a courtsey car that had stop start, but sounds like yours has a fault.

Russ

My wifes 2008 1.8D C max will stall quite easily from start if you dont rev it enough. Easily done as its so quiet inside. My previous passat 2ltr diesel was the same. Only my experiences if taking off too gently.
 
I guess I need to hear if anyone else has the same problem, to see if it is normal.

Asking a dealer seems an excuse for "~£120, no fault found"...

I put it down to the car being designed as an auto, the manual is a bit of an afterthought.
 
i think the OP has a vehicle with the stop-start feature that is not restarting when it should do, or is stopping when it shouldn't

Isn't it supposed to stop when you come to a holt? If so, how are you doing 5mph on a restart?

Definitely sounds faulty
 
When you stop, go to neutral and release the clutch, put your foot on the brake it stops the engine.

As you put the clutch down to go into first it starts the engine, so long as you keep the clutch down for say 2-3s you are fine.

If you leave hardly any time, say a sec or less, for the engine to start, it stalls but restarts itself when you did the clutch.

If you wait between 1 and 2 secs, even though the revs may read ~1500, it will pull
away but may stall in the process.

The times are subjective, I have not been able to measure it.

This can be a real pain if you end up rolling onto a mini roundabout at 5-10 mph, wanting to get out of the way of whatever is approaching, needing both hands to steer (no power assist) while trying to switch the ignition all the way off and back on, and being ready to stamp on the brake if you cannot get round the roundabout.

The car is under warranty so in theory they could fix it, but it feels like inflexible software to me.

From my limited experience, unless it comes up on the screen as an error code, or it is hanging of it feels like MB will duck it.
 
I hate stop start. Always turn it off.
I don't know how you are getting the computer to turn it off at 10mph though?
 
All these complex systems rely on information from simple sensors or switches to tell them what's happening between driver and machine. Sounds as if its getting conflicting information leading to weird behaviour. Could be something as simple as a dodgy/loose position switch on the clutch release pedal/ accelerator.
 
Brake switch causes plenty of strange faults on the older models that's for sure.
 
Turn off stop start its a pain in der a**

You need a different driving technique on the deisels,
not like an old deisel where you could go along engaging/disengaging the clutch in traffic without touching the throttle.









.
 
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Certainly agree it is not like the old high torque, can't stall diesels.

My wife only drives autos (but has manual license), even with the stop-start off she could barely drive this.

Back to the point, does anyone else get this problem - or for that matter does it work for anyone?
 

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