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  • FIRST POST
    • kpwll
    • By kpwll 18th Jul 14, 10:06 PM
    • 3,865Posts
    • 12,291Thanks
    kpwll
    stop/start
    • #1
    • 18th Jul 14, 10:06 PM
    stop/start 18th Jul 14 at 10:06 PM
    Can you please tell me if you can turn off or over-ride a stop/start facility on any/all cars with this function? Thank you.
Page 3
  • topdaddy
    *sigh*

    The car is at a certain temperature with the heater on, right?

    With the engine off in stop / start mode the fans will continue to run.

    Once the car can no longer sustain that temperature when the car has switched off due to stop / start, it will restart the car.

    That may take a minute, it might take 10 minutes. There will of course be hot water in the water system - you do know it doesnt cool down instantly, dont you? So it will use what latent heat remains in the cooling system in the mean time.

    You'd have been one of those people who laughed when it was first suggested the world was round wouldnt you?
    Originally posted by motorguy
    The heater wont work like that, it would be stupid to think it would. Your not smart enough for me to talk to any more
    • F1F93
    • By F1F93 20th Jul 14, 12:38 AM
    • 363 Posts
    • 203 Thanks
    F1F93
    The heater wont work like that
    Originally posted by topdaddy
    Erm, yes it does...
    The fans continue to run. If the temperature drops too low or rises too much (depending on what temperature it's set at) the engine will restart.
    • IanMSpencer
    • By IanMSpencer 20th Jul 14, 12:47 AM
    • 1,480 Posts
    • 1,090 Thanks
    IanMSpencer
    The heater wont work like that, it would be stupid to think it would. Your not smart enough for me to talk to any more
    Originally posted by topdaddy
    Mercedes have had a residual heat system in their cars for years - on a 1990s Merc C class you could press a button while the engine was off and still run the heating fan. The heating system presumably uses the way that water can circulate in a home heating system - gravity. I would presume that this is adequate for the modern systems - anyway at the moment the major drain is the aircon.

    The current C class BlueEfficiency system is built by tweaking the system a bit, stronger starter motor, bit more battery capacity (though Mercs have always had high capacity batteries) and little tweaks to make it very easy to start. When it restarts it barely turns over before it has caught. I don't think there is much overhead in terms of weight, just the expense of some better componentry and management systems.

    It stops when stationary, but only if various conditions are met - sufficient charge in the battery, no excessive demands, not too many restarts in a short period. It has an indicator to show when it is available.

    In terms of control, Merc have a very short hold on the brake so when you release the footbrake there is about a second before the footbrake actually releases - allowing you to transfer the foot to the accelerator - compensating for the lack of auto creep that you usually have to stop rolling back while the engine is starting, triggered by the release of the footbrake. However, a double press on the footbrake provides a hold function which releases on pressing the accelerator which then triggers the restart. As the Merc foot operated parking brake is a pain in the butt, the hold feature is a Godsend. I would not use the parking brake in normal driving. though at least the new version has lost the mighty bang of the older versions' release.

    Stuck on the A1 last week, slow creeping allowed about 5 restarts and then a long stand eventually caused it to time out. After a run of a minute or two at about 40mph it re-enabled and stayed off for the remainder of the stop start which lasted about 20 minutes.

    When did you last have a car that didn't start properly?
    Last edited by IanMSpencer; 20-07-2014 at 12:51 AM.
    • basill
    • By basill 20th Jul 14, 10:30 AM
    • 1,228 Posts
    • 587 Thanks
    basill
    I have a Vaux Insignia, stop start works fine and can be disabled with the eco button.

    One quirk is that when stopped, the engine will start up if the door is opened, made me jump first time that happened!

    B
    • GwylimT
    • By GwylimT 20th Jul 14, 10:36 AM
    • 6,227 Posts
    • 11,736 Thanks
    GwylimT
    The heater wont work like that, it would be stupid to think it would. Your not smart enough for me to talk to any more
    Originally posted by topdaddy
    All my years of being a vehicle mechanic and a driver if a stop/start vehicle must be a huge lie.
    • motorguy
    • By motorguy 20th Jul 14, 10:41 AM
    • 19,744 Posts
    • 12,409 Thanks
    motorguy

    The heater wont work like that, it would be stupid to think it would.
    Originally posted by topdaddy
    Oops. Now you've just made a fool of yourself in front of everyone.

    Your heater is just a fan blowing air through a core matrix of heated water.

    When the car knocks off the water doesnt instantly go cold, so the fan can continue heating the car with the latent heat in the core. Once it cools down too much the car restarts, starts circulating the water again and hey presto more hot water to be used to generate heat in the car.

    I didnt think this was rocket science?

    I take it you treat things like torches with suspicion?

    Last edited by motorguy; 20-07-2014 at 10:51 AM.
    • atrixblue.-MFR-.
    • By atrixblue.-MFR-. 20th Jul 14, 11:25 AM
    • 6,705 Posts
    • 4,644 Thanks
    atrixblue.-MFR-.
    The heater wont work like that, it would be stupid to think it would. Your not smart enough for me to talk to any more
    Originally posted by topdaddy
    please stop, my sides are splitting from laughing too much. In a stop start car, the heater matrix core fan will continue to supply hot air into the cabin when the engine is in eco stop mode, theres a temp sensor on the matrix, as so when the temp hits a low the engine will restart and provide hot water back to the matrix and heat the core again this is known as auto start feature (where you haven't manually depressed the clutch to engage the engine to start).
    Edit didn't sea motorguy had explained already!.
    Last edited by atrixblue.-MFR-.; 20-07-2014 at 11:29 AM.
    • neilmcl
    • By neilmcl 20th Jul 14, 12:28 PM
    • 13,913 Posts
    • 10,391 Thanks
    neilmcl
    One quirk is that when stopped, the engine will start up if the door is opened, made me jump first time that happened!

    B
    Originally posted by basill
    Not much a quirk but a safety feature I'd imagine. Stop/start systems are disabled as soon as you remove your seatbelt or open the car door etc. With keyless systems, like the BMW, it will switch the engine off fully rather that restart the engine.
    • pulliptears
    • By pulliptears 20th Jul 14, 1:45 PM
    • 13,764 Posts
    • 23,395 Thanks
    pulliptears
    My journeys tend to be so short the stop/start wouldn't kick in anyway, and if my journey is longer than usual it's almost always outside of rush hour traffic so again, it doesn't kick in.

    I forgot to turn it off on Friday, pulled into the petrol station and didn't realise the engine had stopped until I went to pull forwards into a pump and it restarted.

    It's a shame it can't be disabled completely rather than having to physically turn it off every time you start the car.
    "Gggggrrrrrr Rrrraaaahhh Rrrrrrggghhhhnn" - Chewbacca (The Empire Strikes Back)

  • topdaddy
    The heater cannot work like that. The fans will work the heater wont as the coolant will not be circulating. That happens when the engine is running.fact. made your selves look silly. Pure mse.
    • DUTR
    • By DUTR 20th Jul 14, 2:01 PM
    • 12,339 Posts
    • 7,002 Thanks
    DUTR
    The heater cannot work like that. The fans will work the heater wont as the coolant will not be circulating. That happens when the engine is running.fact. made your selves look silly. Pure mse.
    Originally posted by topdaddy
    Your description isn't making sense, the water pump circulates the coolant around the warm engine regulated by the thermostat, there is a second radiatior, called the heater matrix, that warm air is convected into the cabin.
    • colino
    • By colino 20th Jul 14, 2:07 PM
    • 4,936 Posts
    • 2,514 Thanks
    colino
    Even with the weight of the bigger battery and allegedly beefier starter motors, there don't appear to be any major, common failures popping up. VAG Greenlines don't even appear to let you switch them off interrogating the ecu (obviously a deliberate block because you can with other models). Only two failures that could possibly be attributed to start/stop were on two very high mileage Octavias. The problem on each was the starting gear teeth on the flywheel literally wearing out causing embarrassing non-starts. Labour heavy fix too.
    • gilbert and sullivan
    • By gilbert and sullivan 20th Jul 14, 2:11 PM
    • 3,162 Posts
    • 2,140 Thanks
    gilbert and sullivan
    The heater cannot work like that. The fans will work the heater wont as the coolant will not be circulating. That happens when the engine is running.fact. made your selves look silly. Pure mse.
    Originally posted by topdaddy
    The heater radiator doesn't cool instantly, the fan will blow the diminishing warmth out of the heater rad, probably take 2minutes depending on the temp.

    If you turn your engine off manually but leave the fan running the heater doesn't blow instantly cold, exactly the same.

    I wonder if stopstart equipped cars are clever enough to switch to recirculation to preserve the residual heat in the radiator.
    • atrixblue.-MFR-.
    • By atrixblue.-MFR-. 20th Jul 14, 2:21 PM
    • 6,705 Posts
    • 4,644 Thanks
    atrixblue.-MFR-.
    The heater cannot work like that. The fans will work the heater wont as the coolant will not be circulating. That happens when the engine is running.fact. made your selves look silly. Pure mse.
    Originally posted by topdaddy
    OH please stop , water that's hot sits in the matrix and cores (just like a radiator) this is then governed by a temp sensor, the water remains hot inside the for a while (these matrixes are larger than conventional ones to carry slightly more water) and have a multi speed fan resistor on them to throttle the fan back slightly when the engine is off not over cool when water isnt flowing in and out of the matrix.


    old style ones tend to go cold in 2 mins because the fans remains at a high speed, these days the fans (inc rad fan)throttle down when stationary with start stop enabled even when on high speed. coupled with the temp sensor the software in the ecu prevents the matrix going too cold and will start the engine to prevent the cabin getting cold.


    even with the engine OFF with stop start my proceed has sat at junctions for 5+ mins and ive been toasty warm inside then auto start will kick in when the temp hit the number its governed by to auto start if the outside ambient temp is above a certain number auto start will not kick in. this is all linked in with the software.
    Last edited by atrixblue.-MFR-.; 20-07-2014 at 2:27 PM.
  • topdaddy
    OH please stop , water that's hot sits in the matrix and cores (just like a radiator) this is then governed by a temp sensor, the water remains hot inside the for a while (these matrixes are larger than conventional ones to carry slightly more water) and have a multi speed fan resistor on them to throttle the fan back slightly when the engine is off not over cool when water isnt flowing in and out of the matrix
    old style ones tend to go cold in 2 mins because the fans remains at a high speed, these days the fans (inc rad fan)throttle down when stationary with start stop enabled even when on high speed. coupled with the temp sensor the software in the ecu prevents the matrix going too cold and will start the engine to prevent the cabin getting cold.
    even with the engine OFF with stop start my proceed has sat at junctions for 5+ mins and ive been toasty warm inside then auto start will kick in when the temp hit the number its governed by to auto start if the outside ambient temp is above a certain number auto start will not kick in. this is all linked in with the software.
    Originally posted by atrixblue.-MFR-.
    youre laughing but agreeing with me?
    the heater will not work. It will not heat.
    Eg. An engine up to temp that is then stopped. The ignition is switched to appropiate position(I possibly depending on ignition key setup) then the heater is switched on. Fans rotate and air flows. Then the heater control is moved from blue(or cold or low numerical temp etc again depending on car). This will not heat the cambin. The heater wont heat. The heater wont work.
    • colino
    • By colino 20th Jul 14, 3:18 PM
    • 4,936 Posts
    • 2,514 Thanks
    colino
    topdaddy are you being deliberately thick, a troll or a 5 year old wannabe?
    • motorguy
    • By motorguy 20th Jul 14, 3:24 PM
    • 19,744 Posts
    • 12,409 Thanks
    motorguy

    youre laughing but agreeing with me?
    Originally posted by topdaddy
    No, no. We're laughing at you, not with you.


    the heater will not work. It will not heat.
    Eg. An engine up to temp that is then stopped. The ignition is switched to appropiate position(I possibly depending on ignition key setup) then the heater is switched on.
    Originally posted by topdaddy
    No need to move the ignition key. You arent really grasping how stop / start works are you?

    You're driving along. You have the heater on to keep the car warm. You come to a junction, or to an idle. The engine stops because the stopstart functionality has kicked in (assuming you've moved to neutral, foot on brake, foot off clutch) and the heater continues to run on, taking any remaining heat out of the matrix. Once the car CANNOT maintain that heat, the car will restart so that it can.

    If you had not the heat previously on, and in the scenario whereby you put the heat to HOT and put the blowers on, the car would restart itself, if it needed to to get the cabin to your desired temperature.


    Fans rotate and air flows. Then the heater control is moved from blue(or cold or low numerical temp etc again depending on car). This will not heat the cambin. The heater wont heat. The heater wont work.
    Originally posted by topdaddy
    If that scenario arises, ie, the car has engaged engine off via stop start, and you previously hadnt the heater on, then the car will restart to enable the cabin to be heated.

    I really didnt think this was difficult stuff.
    Last edited by motorguy; 20-07-2014 at 3:27 PM.
    • anotherbaldrick
    • By anotherbaldrick 20th Jul 14, 3:39 PM
    • 2,308 Posts
    • 1,250 Thanks
    anotherbaldrick
    Quote Motorguy
    I really didnt think this was difficult stuff.

    It is amazing how some manage to get their underdungers in a total twist about something that is basically dead simple
    You scullion! You rampallian! You fustilarian! Iíll tickle your catastrophe (Henry IV part 2)
    • atrixblue.-MFR-.
    • By atrixblue.-MFR-. 20th Jul 14, 3:40 PM
    • 6,705 Posts
    • 4,644 Thanks
    atrixblue.-MFR-.
    No, no. We're laughing at you, not with you.



    No need to move the ignition key. You arent really grasping how stop / start works are you?

    You're driving along. You have the heater on to keep the car warm. You come to a junction, or to an idle. The engine stops because the stopstart functionality has kicked in (assuming you've moved to neutral, foot on brake, foot off clutch) and the heater continues to run on, taking any remaining heat out of the matrix. Once the car CANNOT maintain that heat, the car will restart so that it can.

    If you had not the heat previously on, and in the scenario whereby you put the heat to HOT and put the blowers on, the car would restart itself, if it needed to to get the cabin to your desired temperature.



    If that scenario arises, ie, the car has engaged engine off via stop start, and you previously hadnt the heater on, then the car will restart to enable the cabin to be heated.

    I really didnt think this was difficult stuff.
    Originally posted by motorguy
    He's comparing it to a conventional heater matrix, based on a car (without stop start) that when you turn the ignition off, then back on without starting the heater will remain cold, but the heater matrix in a stop start is bigger and different to conventional ones, with the addition to a temp sensor and a speed resistor that is based upon 14v on the actual fan (not the fan speed selection resistor) when car is running 14V current, when car isn't running 12v current, when 14 v isn't sensed by the resistor, it throttles back the fan when stop mode is in effect to prevent the fan acting as a cooler! he never clicked on why in some cars you can blast the heater then when you come to stop it seems like its not blowing so hard, then when you pull off and accelerate it starts blowing hard again! this is because the fan in the matrix has its own speed resistor independent to the fan selection speed resistor in addition to the heaters that don't go off instantly they slowly cool after about 10-15 mins without auto start it will go cold but the ECU wont let it get to that stage!.


    I give up explaining it now, as well other will, if he don't get it now he never will let him think he's right, and the rest know he's wrong.
    Last edited by atrixblue.-MFR-.; 20-07-2014 at 3:45 PM.
  • topdaddy
    No, no. We're laughing at you, not with you.



    No need to move the ignition key. You arent really grasping how stop / start works are you?

    You're driving along. You have the heater on to keep the car warm. You come to a junction, or to an idle. The engine stops because the stopstart functionality has kicked in (assuming you've moved to neutral, foot on brake, foot off clutch) and the heater continues to run on, taking any remaining heat out of the matrix. Once the car CANNOT maintain that heat, the car will restart so that it can.

    If you had not the heat previously on, and in the scenario whereby you put the heat to HOT and put the blowers on, the car would restart itself, if it needed to to get the cabin to your desired temperature.



    If that scenario arises, ie, the car has engaged engine off via stop start, and you previously hadnt the heater on, then the car will restart to enable the cabin to be heated.

    I really didnt think this was difficult stuff.
    Originally posted by motorguy
    Stop/start or a normal iginiton the heater wont function without the engine on. End of.Im laughing at all of you because it displays how poor this forum is .
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