 | Home > Puma (Tdci) > How does it know? |
 
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 19718  
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Good question! I'm thinking speed sensing some how, although with reverse I'm not sure?
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22nd Jun 2014 11:48pm |
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| grafty99 Member Since: 15 Aug 2012 Location: North Devon Posts: 4784 
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Doesn't it know if it's in low box by the transfer box switch? 2002 90 Td5 Station Wagon
1990 Vogue SE Triumph Tiger Explorer 1200 Td5 90 Thread http://www.defender2.net/forum/topic50767.html Tdi 110 Thread https://www.defender2.net/forum/topic69562.html RRC Thread http://www.defender2.net/forum/topic54492.html Instagram http://www.instagram.com/george_grafton |
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23rd Jun 2014 12:09am |
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| grafty99 Member Since: 15 Aug 2012 Location: North Devon Posts: 4784
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And therefore low reverse, low first though I couldn't say, speed vs revs? 2002 90 Td5 Station Wagon
1990 Vogue SE Triumph Tiger Explorer 1200 Td5 90 Thread http://www.defender2.net/forum/topic50767.html Tdi 110 Thread https://www.defender2.net/forum/topic69562.html RRC Thread http://www.defender2.net/forum/topic54492.html Instagram http://www.instagram.com/george_grafton |
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23rd Jun 2014 1:00am |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731  
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Contacts on gear selector/lever? Tell someone you love them today because life is short.
But shout it at them in German because life is also terrifying and confusing... |
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23rd Jun 2014 6:02am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6266  
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isn't the jack idle the same as antistall and works in all gears?
otherwise like you say 'how does it know'? |
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23rd Jun 2014 12:42pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16983 
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There is a high/low switch on the transfer box which tells it - you guessed - if it is in high or low box. This is used for idle jack and also for controlling which TPS map is used for throttle repsonse (so larger pedal movements are needed in low box).
There is a difflock warning light switch on the ttransfer box which does what you expect. There is a reversing light switch on the main gearbox which is used for the reversing lights. These are the only connections to the transmission assembly (at least they were the only ones on mine when I removed and refitted it a week or two ago). The clutch switch is also used for the idle jack (idle jack is turned off when the clutch is pressed). Idle jack definately only works in low first and low reverse, it does not work in any other gear (try it - let the vehicle run at tickover in low second, it'l; be about 800 rpm. In low first it'll be 1000rpm). Anti-stall, something quite different to idle jack, works in all gears but only when the throttle isn't pressed. I have to conclude that it is based on a comparison of wheel speed (from the speedo sensor) and engine speed, but it seems an oddd way implementing it. I suppose it saves the engineering costs involved in modifying the MT83 box. |
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23rd Jun 2014 1:14pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 19718
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It's ECU monitored / controlled (I'd have thought) so it makes sense I think for it to be more electronic based than physically switched.
What ever it is, it us really good and worth it's weight in gold. It's lovely to greenlane on tick over and let it drives it's self so you can enjoy your surroundings. |
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23rd Jun 2014 1:19pm |
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| Natlas Member Since: 20 Mar 2013 Location: West Sussex Posts: 460 
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My MY2013 seems to have an idlejack that works on at least first, second and third, haven't really checked it in other gears, just noticed during use, so maybe there is more than one version of this. 2.2 90 XS
88" Series One Old Norton 
Minerva |
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23rd Jun 2014 2:29pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16983
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That's interesting John! Perhaps there's been a change for MY13. My MY07 2.4 is certainly not like that - if you drive off in low second or above without touching the throttle there is no increase in engine speed, but in low first and reverse there is an immediate increase.
Mind you it seems an odd change if that's what it is, since the reason for idle jack is to reduce the risk associated with the exceptionally low first and revers gears during steep loose descents, where on standard tickover control would probably be lost as the engine braking would exceed the available traction. This argument doesn't hold up for the higher low range gears. Curiouser and curiouser, as Alice reportedly said! |
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23rd Jun 2014 3:36pm |
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| JR Member Since: 07 Dec 2012 Location: Auchtermuchty Posts: 532  
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Caterham, Anti-Stall only works in low 1st & low reverse and even then it is still possible to stall in low 1st occasionally.
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23rd Jun 2014 7:08pm |
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| Lorryman100 Member Since: 01 Oct 2010 Location: Here Posts: 2686 |
If you let the defender off the brake on a gradient out of gear and let it roll forward, the engine revs rise a little. So the only way the EMS can actually know that the vehicle is moving is by the 4 x ABS wheel speed sensors.
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23rd Jun 2014 8:31pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16983
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Sorry. JR, wrong way round!
Antistall works in all gears, but only when there's no throttle pedal input (try pulling away in 2nd gear without using any throttle - it's easy if you're gentle with the clutch!) Idle jack only works in low 1st and low reverse (and is nothing whatsoever to do with AS). Lorryman, I think that's triggered off the speedo drive not ABS sensors. Mine does it but doesn't have ABS (thank goodness). |
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23rd Jun 2014 8:37pm |
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| martinfiattech Member Since: 13 Nov 2013 Location: leicester Posts: 422
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As I`am not familiar with the Visteon engine management system, give me bosch any day so this is the bosch system.
I would understand that the control unit would begin with engine start, vehicle speed signal 0 mph, engine at idle, (weather this message is delivered via CAN or analog inputs is unimportant). Vehicle`s with stop start systems will have a netural position sensor on the gear lever, similar to an automatic gearbox. One would assume the ecu is programmed to take it for granted that we pull away in either first or reverse gears. Throttle position IDLE (closed throttle) Clutch switch closed (pedal not pressed) As soon as the clutch is pressed the engine ecu sees this and starts to ready it`s self to raise the idle speed, as and when required. The vehicle speed pulse sent to the engine ecu, via the abs system, or whatever speed pick up is used. This will confirm the vehicle is underway, so the engine speed wil be increased proportionately to the demand required. Easy innit, this was a common complaint on early fuel injected cars, as the idle air control valve would try to counter act the drivers inability to correctly control the clutch, thus a lot of stupid customers would come in moaning. We then had the task of teaching these dim wits how to drive a modern car, this was no fun at all. Excuse the spelling I`am better with spanners and wires. |
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29th Jun 2014 2:09pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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if that's right it would be same as gear counters on a bike but its a bit easier on a bike as it a Sequential gearbox
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29th Jun 2014 3:40pm |
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