fly by wire accelerator maybe?

[melb100]

Hi

newbie here,

okay I have an 04 1.8 tdci, where I am experiencing an issue with braking coming to junctions or traffic light situations etc, where I can feel the car wanting to keep going when I get down to around 10 mph while pressing the brake, and I have to press the clutch in to stop this happening. Tried this in an empty car park, where I press the brake then off again and it moves along at around 10 mph without even pressing the accelerator, it does this cold or hot and is not revving high, it seems to change gear ok with the revs dropping off to tick-over quite quickly between changes. Not using the car while its doing this, so any ideas what might be wrong here? 

thank you.

[Russ]

The car will want to keep going unless you put the clutch in because the gearbox is driving the front wheels! If you didn't put the clutch in around 10 mph the car would start 'jerking' and start to stall !

[Micro]

Are you used to an Automatic? This is standard behaviour on a manual car, the engine is always running, and so if you have the clutch released you will always get transfer of power to the wheels (tickover in 2nd is about 10mph) - the car will attempt to not stall, so will fight you pressing the brake if you get too low without dipping the clutch.

[jmurray01]

There is no way to get to less than 10MPH in a manual without the clutch depressed, unless you are in 1st gear.  A petrol would easily stall in that situation, but a diesel will fight and try to keep you moving in order to avoid going below idle speed. 

[Tdci-Peter]

Certainly sounds normal to me. The power of a diesel at tickover is impressive.

On Sunday, I was pulling a heavy trailer along a track, dead slow as there were people walking about. 1st gear, not touching the throttle. The track steepened up a lot through a gateway, the car just pulled effortlessly through, the engine note deepening as the system responded.

It can be quite alarming if you are not prepared for it. Also, when you slow down in gear, the idle control system will kick in, a little bit, appreciably above normal idle revs, it needs to do that to stop the revs dropping below idle, the high compression means the stall point is not far below the 800rpm idle point. That is what my car does.

 

[melb100]

Thanks for all your replies, I have never owned a diesel before so it sounds like this is normal. @tdci-peter, what you have described when towing a trailer is what I experienced the other day when trying the car around the block (no trailer though) "not touching the throttle" but the only difference I was in second gear, and the road goes up an incline in part but it just carried on effortlessly. 

[Tdci-Peter]

5 hours ago, melb100 said:

up an incline in part but it just carried on effortlessly

If the engine can run smoothly at these low revs, then it all sounds perfect

It is a bit eery at first, but I really like it now, just keeping going.

One word of advice: Do not let the engine labour. On the dead flat, you can do this in 3rd, but change down before the engine gets at all juddery. Use 1st for crawling up steep hills.

High torque & low rpm are Not good for the DMF.