Evening people, hope someone can point me in the right direction please, fiat ducato x250 3litre 160hp motorhome
As title I have this 'problem' where the tick over speed increases all by it's self it's cause me no other effects van runs perfect apart from this.
I can start van leave running and it may or may not happen, I can be running for a hour or so and nothing no set patten, but when it does it increases to about 1200rpm and stays there but strangely if I turn off and restart it clears itself and may not do it again but then again it may within 15mins ?
Hopefully I have explained clearly and some one can help

Thanks
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Newbie still learning

First place to start is the earth straps. They are known to cause a lot of problems, there is one from battery to frame the other from engine/gearbox to frame. if this fails it could be an alternator fault.


Mike

Read this thread to the end.

https://www.fiatforum.com/ducato/312784-x250-ducato-2-3jtd-alternator-fault.html

Mike

taffybloke said:

First place to start is the earth straps. They are known to cause a lot of problems, there is one from battery to frame the other from engine/gearbox to frame. if this fails it could be an alternator fault.


Mike

Click to expand...

Earth strap changed some months ago, having previous read about this problem, I will have a research on the the alternator theory, thank you

It seems a commom fault and narrowed down to two things, one is the earth strap, two low output from alternator, I will look again at my earth strap to begin with

Have you changed both straps or just one? You need to check both.


Mike

I have only changed the one from gearbox to chassis, where is the other one ?

Thewad said:

I have only changed the one from gearbox to chassis, where is the other one ?

Click to expand...

I think (?) they mean the one from the cab battery to the cab floor. Without looking, I can't remember if this is a braided strap or solid cable. Never thought to change ours though as it's the one under the bonnet that's most likely to break down due to the conditions it lives in.

I was having problems with my alternator, to find if there was a fault I used a multimeter and ran through a procedure that check voltages and resistance values. One of those was alternator to earth resistance. That's an easy check and won't take long.

i assumed this as well,

Deefordog said:

I think (?) they mean the one from the cab battery to the cab floor. Without looking, I can't remember if this is a braided strap or solid cable. Never thought to change ours though as it's the one under the bonnet that's most likely to break down due to the conditions it lives in.

Click to expand...

I have assumed this as well, but i was pretty sure an insulted earth cable

If you have diagnostics check the intake air temp, coolant temp could be being fooled into thinking its stone cold.

Thewad said:

I have assumed this as well, but i was pretty sure an insulted earth cable

Click to expand...

It is an insulated strap but it can still cause problems. the cable ends are pressed fittings and deteriorate, it can develop small cracks and heats up on engine start, You may as well check it as it is often forgotten hidden under the floor.


Mike.

No quite the same problem but an interesting thread,

https://www.fiatforum.com/ducato/294963-fiat-ducato-2007-not-charging.html

Morning all, picked up motorhome to look at earth straps etc, drove the 5 miles to home no problems left running for a while again no problem.
Removed earth at battery end looked perfect if I am honest but never the less cleaned with emery tape replaced.
Now under the bonnet to completely remove existing and new earth strap, where strap bolts to engine mount I throughly clean to almost a polish same with strap ends lightly greased and replaced all going according to plan. :-D
There is no 'but' I am pleased to say when I started van I was pleasantly surprised at how much quicker the starter motor turned it always sounded a bit lazy, and so far,after long road test no increased tick over so as it stands mildly optimistic that my problem is cured, will update in due course for you all

Happy Christmas

I must say it is not often you read about a problem immediately before getting it ! I was reading this thread last week, started my motorhome this week and thought 'thats odd the rev are building up' so came back and re-read this thread.
Same happened today, so whilst the revs were settled at 1200 I checked the motorhome control panel and it showed both cab and leisure batteries at 12 volts. The ignition light was on too. I gave the throttle a press and increased the revs, there was a click of a relay somewhere and the ignition light went out. I checked the volts again on the panel and both now showing as 13 volts. Revs also dropped back to normal.

Straps it is then !

andytw

If I read your post correctly you have to yet to clean/change straps ? if so fingers crossed for you, hopefully it's that simple

Hi, yes you did read correctly. I have done nothing but read this thread and witness the problem. Will have a look some time this week.

andytw

Removed and cleaned up both cables this morning. Engine was then started up, no increase in revs, no ignition light and both batteries showing at 13.5 volts or so. Looking OK but obviously time will tell as the problem is intermittent by nature.

I must say I did struggle to find the engine cable until I removed the top of the air filter and then I could see it. The bolt holding this cable to the engine was not exactly loose but was not too tight either. Anyway all very clean and very tight now.

andytw

Sounds like a winner to me andy, the fact that your light has gone out plus increase in voltage points to problem sorted