 | Home > Puma (Tdci) > ENGINE RUNNING BUT NO REVS WHEN ACCELERATOR PRESSED DOWN?? |
 
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| GREENI Member Since: 22 Aug 2010 Location: staffs Posts: 10383  
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I’m guessing there’s a potentiometer on the pedal. I had this happen on my Ibex that used a td5 pedal, i took off the plastic cover and gave it a squirt of wd40, fine after that. Though not sure on a puma if it may be something else.
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30th Apr 2020 12:34pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17626 
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TDCi pedal is similar to the TD5 (I don't know if it is actually the same part) and has throttle position potentiometers to determine pedal depression and signal that to the ECM. It is possible that you have a faulty pedal assembly, but it also occurs to me that you may have had a fault which put you in "limp mode", and cycling the ignition has reset this.
My advice would be to get hold of a fault code reader and check for stored DTCs before you start replacing things. |
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30th Apr 2020 12:59pm |
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| gasman07 Member Since: 18 Apr 2020 Location: south wales Posts: 7  
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Thanks guys
will look into it over the next 2 weeks but very helpful and very much appreciated  |
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30th Apr 2020 1:26pm |
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| Matt110 Member Since: 29 Jun 2014 Location: UK Posts: 685
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I would have thought it's pretty unlikely that the issue is down to the accel pedal to be honest. They do have potentiometer tracks in them, but they are twin tracked to prevent exactly this happening, and throw a MIL light up if one of the tracks fails (the resistance changes and the module then knows it's lost a track). So you would normally get a MIL light up and a still functioning pedal rather than a completely failed pedal.
I'm not great at the list of alternatives that are common on puma but sure others are  |
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30th Apr 2020 2:59pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17626
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I'm not sure of the TDCi is twin (doubtful) or triple-tracked (more likely, I think) like the later TD5s. The triple track pots have quite a lot of self-detection built in, even the twins have proportional rising and falling voltages, and as a check monitor that the sum remains constant. This enables the detection of spot faults on either track.
Generally a faulty throttle pot will result in an intermittent hesitation fault, which if persisted, i.e., it happens a sufficient number of times in a short period, will result in a DTC and potentially limp mode. I do tend to agree that from what the OP has written is is more likely to be something completely different causing the ECM to enter limp mode, rather than the pedal causing the problem. With diagnostic equipment it should be easy to establish this and it is certainly worth doing before getting spendy with parts that may not be at fault. |
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30th Apr 2020 3:14pm |
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| llessur Member Since: 15 Nov 2011 Location: Hereford Posts: 151
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Just for info I have had this happen on several defender 2.4 's and as you say ,if you cycle the ignition it fixes it.
I have always put it down to starting the engine before the ECU has finished it's self checking. I now wait 5 seconds after the glow plug light goes out, and haven't had the issue for the last 6 months. Might be coincidence. |
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30th Apr 2020 7:18pm |
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