 | Home > Technical > How can I make it Rev? |
 
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| Alien Member Since: 18 Jan 2015 Location: Bacchus Marsh Posts: 230  
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A brick or a stick?
Maybe worth talking to Mobile Centre to see if it could be done with one of their cruise controls. Contacts in the Sponsors link on the header. Cheers, Kyle. |
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7th May 2016 10:07am |
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| mowcop Member Since: 03 Jul 2009 Location: Staffs Posts: 108  
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I can physically wedge the pedal to the right position, but it's the fact that the revs just drop back down that's the problem.
The PTO is only used while the vehicle is stationary but in 3rd gear, neutral transfer box. |
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7th May 2016 10:20am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17374 
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There's only one way that I know to make it do what you want, and that is to fit the genuine LR hand throttle kit (which includes new ECU software) which was available for this sort of application. The problem is that it is blisteringly expensive - several thousand pounds if I recall from when I looked into it - and as far as I can determine was only available as a factory-fitted, build-time, special-order option.
The problem, as you have found, is that if the ECU detects that the engine is revving but the vehicle isn't moving, it assumes that something has gone wrong and kills the throttle input (in just the same way as it kills the throttle input after a few seconds if you press the brakes when moving, for example when you want to dry the brakes after wading, or keep them dry when wading). It's quite an annoying and unhelpful feature though I can understand the reasoning, but I don't know of any way to disable it. |
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7th May 2016 10:28am |
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| mowcop Member Since: 03 Jul 2009 Location: Staffs Posts: 108
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Anyone know what voltage the speedo display operates at?
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7th May 2016 10:50am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17374
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Speedo is driven by an output from the ECU via CanBus, and will be digital I would think.
If you want to fool the ECU into thinking the vehicle is moving I think you'll have to simulate a speed transducer input from the transfer box. You could try chocking the vehicle, disconnecting both props from the t-box, locking the centre diff, and seeing if you can then run the engine at speed in gear. |
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7th May 2016 12:29pm |
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| mowcop Member Since: 03 Jul 2009 Location: Staffs Posts: 108
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I will see if it will hold revs whilst "free wheeling" later on.
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7th May 2016 1:20pm |
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| neil-h Member Since: 07 Sep 2015 Location: Berks Posts: 30 |
Does the Puma have abs/tcs? As that may cause you trouble because the ECU will probably expect to see speed signals from the wheels as well as the main speedo signal. |
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7th May 2016 2:58pm |
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| mowcop Member Since: 03 Jul 2009 Location: Staffs Posts: 108
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It will hold the revs in neutral and coasting.
Is there any way I can "force" a speed signal into the sender wiring? Has anyone a schematic of this circuit? |
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7th May 2016 3:32pm |
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| mowcop Member Since: 03 Jul 2009 Location: Staffs Posts: 108
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Mine is a ex mod SW so no such luxuries.
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7th May 2016 3:33pm |
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| neil-h Member Since: 07 Sep 2015 Location: Berks Posts: 30 |
http://www.defender2.net/forum/post7305.html There ya go. Problem is the raw signal from the sensor is PWM (pulse width modulation), so you'd need to inject a pulse train into the ECU. Not impossible but not as simple as it could be. |
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8th May 2016 12:47pm |
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| mowcop Member Since: 03 Jul 2009 Location: Staffs Posts: 108
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Osscillator ?
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8th May 2016 2:54pm |
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| miker Member Since: 13 Sep 2015 Location: Surrey Posts: 1763 
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One thing, if the speedo is being driven then the mileage would likely be increasing...
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8th May 2016 4:18pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17374
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Interesting that the vehicle is arse about face, in that the signal goes from transponder to Ipac to ECU, though it actually makes perfect sense given the way a little bit of Canbus was shoehorned in.
I would be slightly surprised if the speed signal is PWM since a varying frequency signal would be easier and cheaper to do. Pete Bell's comment in the linked thread above ("5200 pulses per mile") also suggests that it is a varying frequency, not PWM. Good point about the odometer! |
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8th May 2016 8:15pm |
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| leonvh Member Since: 31 Dec 2013 Location: Plombières Posts: 69  
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I bought a cruise control kit from Nakatanenga and when looking up the manufacturer I noticed they also do a RPM control module specially for PTO purposes.
See also http://lpdk.com/products_ecruise_pto.php Might be worth informing with them as they already do a Defender specific cruise control module. Leon |
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13th May 2016 11:51am |
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