nige223 Posted July 11, 2016 Share Posted July 11, 2016 Hi everyone I'm new to this forum joined only today, I hope someone can help I'm having problems with my 2011 Autotrail on a Fiat Ducato X250 2.3 Lt 130hp. On start up (engine hot or cold ) the engine won't rev above 2750rpm unless I de-press the clutch pedal, after which all is OK. This happens whether I have the cruise control set or not the engine doe's not make excess smoke. On one or two occasions in the past the engine has revved quite high on it's own accord(quite alarming at the time) both times it's been as I have approached a junction/roundabout with the clutch de-pressed. I think this my be a communication problem. What I would like to do is check various connections and cables in the loom for damage,corrosion,and continuity.My question is if I disconnect the negative terminal on the battery will this action cause any problems with the ECU or any other items and will I be able to work on the connections safely?My Cherokee has a factory fitted solar plane I guess that that I should cover the panel to ensure no current is made and shut down the habitation (Sargent) panel.The radio is an after market fit and doesn't require a code .any advise would be welcome.Thank for reading the post. Nige. ;-) Link to comment Share on other sites More sharing options...
euroserv Posted July 11, 2016 Share Posted July 11, 2016 Hello and welcome, First, there is a piece of software in the ECU that prevents excessive revs while the vehicle is stationary; so that appears to be working OK. The only general reason for the engine revs to rise of their own accord is when there is a problem (or apparent problem) with the alternator but this would be accompanied by a warning symbol (battery). To answer your question; no, there would be no problem with disconnecting the battery. When power is reinstated you will have to reset the clock but that should be all. NIck Link to comment Share on other sites More sharing options...
Charles Posted July 11, 2016 Share Posted July 11, 2016 I read somewhere that when diesel engines rev up on their own it's the engine oil leaking through the turbocharger and burning in the engine just as diesel. They have to be stalled to stop them or the engine will destroy itself. I think it was a Land Rover engine in question Link to comment Share on other sites More sharing options...
nige223 Posted July 11, 2016 Author Share Posted July 11, 2016 Hi Charles I don't think it's a turbo oil leak as the vehicle doesn't smoke and uses no oil from one change to the next. I'v had the vehicle from new and it drives just as well now as it did when I first got it.Thanks for the thought though.Nige. Link to comment Share on other sites More sharing options...
EJB Posted July 11, 2016 Share Posted July 11, 2016 Hopefully your post on the FIAT site will get a result! Link to comment Share on other sites More sharing options...
nige223 Posted July 11, 2016 Author Share Posted July 11, 2016 Hi NIck thanks for the input I believe that the ECU restricts some of the fuel to the injectors at rev above some where in the region of 4500rpm and stops all fuel at 5000,to prevent an engine run away. however when I experienced the revving that I mentioned in my post I was off the accelerator and changing down the gears,but the revs did not die away so the depression of the clutch took the load off the engine and the engine revved higher. To me it seems to be a communication problem as I have no warning lights on the dash and reading the ECU shows no current or historical fault codes . If the ECU thinks the cruise control is on (ie communication problem) I don't think it would show a fault, would it not not shut the fuel due to to high revs? The vehicle has only done this twice in almost 30,000 miles. This latest problem at start up seems to be related insomuch as to the operation of the clutch.I am informed that the connections behind the left headlight can be a problem (some are calling it rust junction). I'v also heard about poor earth straps so whilst I check out this current problem I'm going to run a second earth from thee top of the engine to the bonnet scuttle. Thanks for the input Nick good stuff. Nige Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 12, 2016 Share Posted July 12, 2016 EJB - 2016-07-11 3:18 PM Hopefully your post on the FIAT site will get a result! http://www.fiatforum.com/ducato/440628-engine-wont-rev-above-2750rpm.html Link to comment Share on other sites More sharing options...
lancepar Posted July 12, 2016 Share Posted July 12, 2016 Cruise control fault would be my guess as well. B-) Link to comment Share on other sites More sharing options...
nige223 Posted July 12, 2016 Author Share Posted July 12, 2016 Hi Derek I did put a thread on the Fiat forum there are some very informed people on there how ever no one could give an answer as to any potential damage that may me caused to the ECU ect if the battery is disconnected,or if there is a sequence for connection / disconnection. Thanks. Nige. Link to comment Share on other sites More sharing options...
nige223 Posted July 12, 2016 Author Share Posted July 12, 2016 Hi lance that's my assumption also hence the need to disconnect battery ect. I'v heard and read so many things about damaged ECU's and the need for a dealership re-write that I'm reluctant to take the plunge without being certain that disconnection won't cause damage.Thanks for reading the post. Nige. Link to comment Share on other sites More sharing options...
colin Posted July 12, 2016 Share Posted July 12, 2016 I didn't bother answering your thread as Nick has done so before, I've disconected the battery on my van with no ill effects, I guess Nick has done it on countless Ducato's as his company hires them out. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 13, 2016 Share Posted July 13, 2016 nige223 - 2016-07-12 3:56 PM Hi Derek I did put a thread on the Fiat forum there are some very informed people on there how ever no one could give an answer as to any potential damage that may me caused to the ECU ect if the battery is disconnected,or if there is a sequence for connection / disconnection. Thanks. Nige. The Ducato Owner Handbook (probably) relevant to your 2011 motorhome has a “Battery” section. This includes the following advice: “Before performing any operation on the electrical system, disconnect the battery negative cable” This is the standard sequence when there is a need to replace/disconnect a vehicle’s starter-battery - first disconnect the ‘earth’ (the ‘negative terminal' with modern vehicles) then (if the battery is to be removed) the ‘live’. When replacing the battery, reverse the connection sequence - ‘live’ first, then ‘earth’. More detailed guidance here: http://www.wikihow.com/Disconnect-a-Car-Battery As Nick and Colin have said, disconnecting your Ducato’s starter-battery should have no adverse effects other than some display features needing to be reset after battery reconnection. As your vehicle has only exhibited spontaneous revving-up twice in 5 years and near 30k miles (presumably with a wide time interval between those two occasions) and no fault codes resulted, the chances are slim that you’ll establish the reason unless it happens again and either a fault code is produced or the fault can be provoked and demonstrated. I owned my first motorhome for 6 years and it suddenly lost power twice (on widely spaced occasions) during that period. Stopping the motor and restarting it immediately restored full power and I never found out the cause of the power-loss. Nick said “...there is a piece of software in the ECU that prevents excessive revs while the vehicle is stationary; so that appears to be working OK.” This suggests that your inability to rev your Ducato’s motor above 2750rpm on start-up without first pressing the clutch-pedal is normal and not a ‘problem’. There’s a good deal of on-line discussion about the purpose of the ‘clutch switch’, including keeping engine revs up momentarily while shifting gears and disengaging cruise-control. If Nick advises that a Ducato motor’s rev-range is governed after engine start-up until the driver depresses the clutch-pedal I’m in no position to say otherwise - in any case it seems like a sensible technical protective measure to me. If you know that you used to be able to obtain the motor’s full rev-range at start-up in the past without needing to depress the clutch-pedal first, then you may indeed have a problem. If I were in your shoes I’d ask a Fiat Professional agent about the 2750rpm issue. It makes good sense to check the condition of your vehicle’s under-bonnet wiring-loom connections, but it would be worth getting Fiat Professional’s opinion about whether the 2750rpm restriction is designed-in or not. Link to comment Share on other sites More sharing options...
nige223 Posted July 13, 2016 Author Share Posted July 13, 2016 Hi Derek thank you for your reply, I take your advice I will check the connections I will also install a second engine/ gearbox earth cable. As for the 2750 rpm on start up I think as it' is only till the clutch is de-pressed I shall run it for the rest of the season and see what develops .Thank you again and all that read/ posted a reply I hope in the future I may be able to help other users in the same manner. A very appreciative Nige. :-> Link to comment Share on other sites More sharing options...
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