 | Home > Puma (Tdci) > Engine management and brakes |
 
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436   
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guess its normal
other cars are doing the same, ecu doesnt like brake and accelerator signals at the same time and chooses the safe option: braking. Guess it came with the drive-by-wire technology as standard safety measure in case the wires/signals go nuts. Not always convenient with an automatic when you want to keep the torque converter loaded for a quick take off. Makes it hard to do burnouts also.  I noticed that AMG eliminated this reaction of the ECU if you switch off ESP as you are then "on your own" and assumed to be an advanced driver which uses brake and loud pedals simultaneous when giving the ponies a run.
On normal MB's it doesnt make a difference. So maybe a remapper could also take this out so you can load the spinning wheel with the brakes while accelerating in mud or axle twisters to get some traction (if you don't have the ABS/TC package that is)  |
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10th Jul 2012 4:17pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298  
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as mentioned in my previous post which related to poor running upon recommendation I checked all my fuses and the only one that wasn't pushed home fully was the abs fuse. i can't say for sure if it was making a good connection or not however I've done just 2 x 8 miles journeys today and things appear to have improved - however to be honest its too early to say whether its fixed my problem or not so will be keeping an eye on this over the next few days / weeeks and if its fixed I feel like I owe Andrea a big Beer !
so know onto what Blackwolf mentioned....can someone elaborate on how the abs interacts with the ecu / engine and in my case a possible poor connect in the abs fuse ? |
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10th Jul 2012 8:40pm |
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| wslr Member Since: 18 Jul 2010 Location: Wellington, Somerset Posts: 581 
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Looks like 2 fuses feed power to the ABS ECU - A 10A fuse at the CJB F11, and 30A F1 under the seat.
The diagrams show the powertrain ECU connected to the ABS ECU C0504 (pins 10 and 11). C0504 is the big black plug on the WABCO unit under the seat. From reading the Engine Management stuff, it indeed looks like the brake pedal switch tells the powertrain ECU that the pedal has been pressed, which aims to drop fuelling to the engine under braking, and to cancel speed control if the pedal is pressed (Cruise Control???). Not sure why on non ABS, but I expect the switch is still there. Last edited by wslr on 10th Jul 2012 10:48pm. Edited 1 time in total |
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10th Jul 2012 10:46pm |
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| wslr Member Since: 18 Jul 2010 Location: Wellington, Somerset Posts: 581
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Has Brian left the building, BTW? He'd have been on this in a flash.
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10th Jul 2012 10:47pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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wslr......sounds about right - reduced fueling, thats exactly what its been like.
one more thing could this in anyway have an impact on when the engine is turned off ie sometimes the engine switches off nice and smoothly - other times its more like what I'd have expected a commercial truck to have been like 30 years ago (not so smooth......I mean really not very smooth). ? thanks for all the info so far. another 8 miles this morning and I'm beginning to think its all resolved (but I'm not counting on it jus yet) |
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11th Jul 2012 6:33am |
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| wslr Member Since: 18 Jul 2010 Location: Wellington, Somerset Posts: 581
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My 10MY 110 switches on and off with a shake - Always has, every time.
The 2.2 engines don't do this. |
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11th Jul 2012 7:59am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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thanks mate.
mine stops with a shake and I expect that every time as you've said. ony sometimes its alot worse than what I would expect to be normal. do you find the shake is consitant everytime or is it worse sometimes. if constistant could mine being inconsistant be anyway attributed to the issue of the abs / engine management? |
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11th Jul 2012 8:21am |
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| Naks Member Since: 27 Jan 2009 Location: Stellenbosch, ZA Posts: 2637  
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That is odd. I used left-foot braking while on the LR Experience course with the Evoque and that didn't happen. Mind you, the Terrain Response was in off-road mode, so that could be the difference? I have not tried it in my Puma, will do so tomorrow and report back. -- 2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear 2015 Range Rover Sport V8 Supercharged 
Defender Puma Workshop Manual: https://bit.ly/2zZ1en9 Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ |
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11th Jul 2012 8:23am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17353 
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I imagine that the Evoque is set up very differently. I know that my TD5 Disco2 doesn't do this, you can drive quite happily with your left foot on the brake. The Puma however definitely does, I tried it again this morning. Yo have to be moving though, if you are stationary and increase the engine speed, then press the brake pedal, it makes no differemce. If you are moving and press the brake, after a delay of about 5 seconds the engine speed drops right down. It does occur to me that this could actually be a significant nuisance if (like me) you have torque-biasiing diffs. |
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11th Jul 2012 9:11am |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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Surely, the ECU is just detecting the brake signal rather than what the diffs or wheels are doing? Darren
110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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11th Jul 2012 9:45am |
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| Naks Member Since: 27 Jan 2009 Location: Stellenbosch, ZA Posts: 2637
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Or even when negotiating obstacles off-road! In the Evoque I used left-food braking to prevent the TC from kicking in and I could then tackle the obstacles in a much smoother way - even the instructor commented afterwards how smooth I was compared to the others who relied on the TC kicking in. It bugs me that I won't be able to do the same with my Puma --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear 2015 Range Rover Sport V8 Supercharged
Defender Puma Workshop Manual: https://bit.ly/2zZ1en9 Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ |
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11th Jul 2012 10:11am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17353
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True, but my point is that for a torque-biasing diff to work there must be some load on both wheels. If one wheel is airborne, for example, all the power will be transmitted to it, as it would with an open diff. The accepted technique to overcome this is to apply the brakes lightly to load the spinning halfshaft, which will then cause a proportionally greater torque in the non-spinning side (the operation of torque biasing diffs is a little counterintuitive, but in essence there must be some resistance to movement in both halfshafts). However it appears that with a Puma the engine will de-fuel and rev down after five seconds, which may not be optimal. My Defender does not have TC, which will inevitably alter the situation. From the electical manual it appears that there are two inputs to the ECM from the brake light switch; there is an tapping from the actual brake light circuit (input B001 on C0872-E3 from C0075R-2) and one which is dedicated (input B002 on C0872-F3 from C0029R-2). It may be that disconnecting one or other (or both) of these will disable this feature, but it is hard to predict what if any side effects this may have. Anyone like to become the guinea pig? |
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11th Jul 2012 10:36am |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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Blackwolf, does it also do it in low and/or with the difflock on?
i understood the anti-stall has a different mapping when difflock or low range is engaged (dont remember which one, suspect it is center difflock) Just wondering if the LR engineers were clever enough to alter the programming so this issue is not present when driving offroad. And i know that mine (with TC) will keep anti-stalling in low even when I press the brake for longer time, eg a steep decent in 2nd low which should have been taken in 1st low and thus with a bit of brake assist to reduce the speed. |
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11th Jul 2012 12:22pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17353
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Tatra, an excellent question! I don't know, but will try on the way home and post. If the feature is disabled in low or difflock it would make a lot of sense.
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11th Jul 2012 12:24pm |
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