Stalling when braking - really annoying

[rich77]

hello everyone hope you can help have recently my car has held on to a high gear far to long when braking and stalls , i have searched and on here and due to this i cleaned the idle stepper motor and spent hours going over the hosses then all back together and no different :-(.
I am at a complete loss now i have checked all plugs etc all good does anyone have an idea ??
oh not sure it makes a difference but the battery ran flat the other day due to my boys leaving the interior lights on (always blame the kids)
hope someone can help and cheers so so so much in advance

[elnevio]

Might have reset the ECU and therefore all the lovely autobox learning too. What you are describing though with the gears staying in a high gear when braking sounds normal to me. The stalling (or nearly stalling) is quite a common characteristic, although some cars suffer worse than others. It's effectively when the 'gear' disengages (essentially into neutral) that the car stalls. I assume you usually notice it most when hauling up at the end of a motorway sliproad?

[richy rich]

Cleaning of the stepper motor may not be the answer it may need replacing.

[rich77]

Might have reset the ECU and therefore all the lovely autobox learning too. What you are describing though with the gears staying in a high gear when braking sounds normal to me. The stalling (or nearly stalling) is quite a common characteristic, although some cars suffer worse than others. It's effectively when the 'gear' disengages (essentially into neutral) that the car stalls. I assume you usually notice it most when hauling up at the end of a motorway sliproad?





thats exactly the kind of thing so you think it will just sort itself out then ??

and a new one ? they expensive ? that a camskill job ???

and as usuall cheers for the replys great as usuall

[richy rich]

yep camskill do them

[richy rich]

http://www.camskill.co.uk/products.php?plid=m22b0s1399p6902

[rich77]

cheers , thanks very much , reckon this will cure it ???

[bradc]

If you use tiptronic to drop down the gears does the problem still occur?

[rich77]

it does yes , that good or bad news ???

[bradc]

It just means it isn't a transmission change point fault, which is good news I guess ;)

[rich77]

woop woop!!!! you reckon a new stepper motor would cure it then

[Turbo_Steve]

You probably don't even need to do that - just take the idle stepper housing off, clean it out (it will be full of oil and crud) remove the stepper, clean it up very carefully with some sandpaper: I chose to dremmel about 0.5 mm off the edge of mine, which meant the ECU didn't try and use the "dead" spot anymore.

[zentac]

Throttle position sensor would be my guess, its giving a false reading (probably 100% open) which means the car stays in a higher gear and pushes far too much fuel in and overfuels and stalls.

[VR4Kaos]

vacume leak is my guess i had intemitent stalling when i deaccelerated dependent on pipe postion i think found and cured all 3 leaks and it runs gawjus now with nearly twice the power

[rich77]

blimey more help thanks will double check the hoses again , dont know what a throttlr position sensor is though < (hangs his head in shame) is there a guide to doing this i cant find one ? sorry to be such a pain and thanks again

[Turbo_Steve]

Just out of interest, does it do this every time, or just when you have the aircon on / it's really hot out - coming to a complete stop.


Idle stepper issues generally only seem to appear during hot weather, ya see, and generally when you're braking to a stop.
Vacuum leaks are more likely to manifest under any hard braking.

[rich77]

well the last time it happened i was pulling to a stop at a junction with no aircon on ??? puzzling the hell out of me

[elnevio]

The aircon might be a bit misleading - I think the main factors are 1. warm car, after a few miles of motorway/high speed running, and 2. warm weather.

[kinkyafro]

If the ecu loses power the idle point needs to be relearnt but it doesn't take to long (5-10 miles of stop start traffic should see it right).

One issue I had which caused the same problem for me was the crank case breather pipe popped off - but you would have noticed that when you took the airbox off to get to the ICV.