Technical Loss of power just after driving

[P and A]

We have a 2017 motorhome with a Fiat 2.3 engine. We have a problem that no one can detect what is causing it. After starting the engine and driving for about ten minutes sometimes, not every time, the engine loses power. You can still drive it but it will be slow to accelerate and slows down up a hill. It’s just like the turbo has stopped working. If we stop, turn off the engine and restart it, the problem has gone for the rest of the day, but the engine warning light will stay on, maybe for that day, or the next few days sometimes and then goes off. Other days you can drive it for a week or more and this problem never happens. Has anyone any ideas what is causing it. The problem has happened since nearly new, and we have now done 28,000 miles in the motorhome. Thanks.

 

[cris1117]

Sounds a bit like crank sensor breaking down that would be my first try, easy and cheap to do.

Have you had it plugged in, any fault codes stored?

Almost impossible to diagnose without fault codes being read, preferably by a Fiat main dealer.

 

[Keith Spencer]

We have a 2017 motorhome with a Fiat 2.3 engine. We have a problem that no one can detect what is causing it. After starting the engine and driving for about ten minutes sometimes, not every time, the engine loses power. You can still drive it but it will be slow to accelerate and slows down up a hill. It’s just like the turbo has stopped working. If we stop, turn off the engine and restart it, the problem has gone for the rest of the day, but the engine warning light will stay on, maybe for that day, or the next few days sometimes and then goes off. Other days you can drive it for a week or more and this problem never happens. Has anyone any ideas what is causing it. The problem has happened since nearly new, and we have now done 28,000 miles in the motorhome. Thanks.

Hi P and A
1st thing is to get a DTC scan (diagnostic trouble code) and find out why your engine warning light is coming on. You can buy the obd (on board diagnostics) scanners online, but select carefully for one that will work on your vehicle. Not cheap!
Or take it to a garage that understands Ducato's £50 to £100. Normal cost.
Very surprised you haven't already had a scan done with your vehicle being owned from new, and significant mileage!
Without all the diagnosis results you can be second guessing almost every component, blocked fuel filter, blocked dpf, faulty maf sensor, injector and so on.
The ECU is smart and will store historic events of the warning light activations and all the operational parameters of the vehicle at that moment. The scanner will allow the technician to see all this information to make the diagnosis. Beware you can get good and bad diagnostics technician's so try and find a good local person. Remember to use your brain before firing any parts cannons it will be alot less expensive that way.
I think on the 2017/18 onwards models Fiat made the obd port more difficult to access, behind the dash and you require a special adapter cable obd2 to 12 pin, all to prevent theft.

 

[Keith Spencer]

Sounds a bit like crank sensor breaking down that would be my first try, easy and cheap to do.

Have you had it plugged in, any fault codes stored?

Almost impossible to diagnose without fault codes being read, preferably by a Fiat main dealer.

Don't just go firing the parts cannon willy nilly, it will cost you and fix nothing. I agree obd scan is essential 1st step.
Main dealer will have the hardware and software to read the ECU but not necessarily the skills to diagnose the information. Ask round and find a highly recommended person probably cheaper and more skilled.

 

[P and A]

We have taken it to the Fiat main dealer garage that deals with commercials and motorhomes. They could not find a fault or code when they had it on their diagnostic machine. We had a part replaced they thought may be causing the problem at a cost of about £600, but did not solve the problem. It has been to another garage as well and they cannot see a code neither, so no one can diagnose the cause, only suggesting a couple of other parts are replaced that may solve the problem but not guaranteed to, at a cost of between £1200 to £1800.

 

[Communicator]

Sounds a bit like crank sensor breaking down that would be my first try, easy and cheap to do.

Have you had it plugged in, any fault codes stored?

Almost impossible to diagnose without fault codes being read, preferably by a Fiat main dealer.

Crank sensors have been reported as failing, without raising a fault code. However if engine warning light shown then fault codes should be stored.
Further the fact that the problem occurs after about 10 minutes into a journey, the fault seems to be related to the engine warming up. Due to its location, the crank sensor is again a candidate for this.

 

[Keith Spencer]

We have taken it to the Fiat main dealer garage that deals with commercials and motorhomes. They could not find a fault or code when they had it on their diagnostic machine. We had a part replaced they thought may be causing the problem at a cost of about £600, but did not solve the problem. It has been to another garage as well and they cannot see a code neither, so no one can diagnose the cause, only suggesting a couple of other parts are replaced that may solve the problem but not guaranteed to, at a cost of between £1200 to £1800.

You don't say what parts have already been done? Or the other parts they are recommending!
But all they are doing is guessing and it's your money they want to waste.

You can watch this happen so many times on YouTube, people spending £5/6000 and 3 main dealers later. Try watching Pine Hollow Auto Diagnostics, it's excellent, so many cases like yours. So don't be a mug and keep your money until you get an actual accurate diagnosis.

So how to get a diagnosis from what you have said :-
The only way that anyone will be able to give you an accurate guide, is for them to be connected to your ecu (engine control unit) ie the main computer monitoring live data with the scanner when the fault is occurring. They will have to be sat with you in the vehicle whilst it's being driven and checking all the live data parameters.
The fact that you can turn the ignition off and back on and the light goes off(reboot reset), suggests a non critical fault that hasn't developed into a more serious issue with a dtc being generated.
So you could
1 wait until it develops into a more significant fault, but you say you have been using it for a few years already. Not likely to happen.
2 get yourself a good scanner and learn how to use it, then watch things yourself as you drive.
3 find a local guy who is skilled enough and willing to get in the ducato with you at the drop of a hat, when it occurs.

Do not waste your time and money guessing, buying parts and fitting them 95% chance you will end up £1000's worse off and still have the problem.

Intermittent faults are notoriously difficult to diagnose.

 

[Keith Spencer]

Crank sensors have been reported as failing, without raising a fault code. However if engine warning light shown then fault codes should be stored.
Further the fact that the problem occurs after about 10 minutes into a journey, the fault seems to be related to the engine warming up. Due to its location, the crank sensor is again a candidate for this.

If it is a crank sensor then attaching an oscilloscope with back probes and monitoring the signal will show you any changes with temperature and could be quickly ruled out as the cause.
The trouble is we don't have the knowledge to know how the ECU programming team have written the software in Italy. They could have designed it for certain conditions to show an engine light and place the engine in mild limp mode until the ignition key is turned to off for the reset. Many manufacturers do this as a means to protect their engine just in case it's the beginning of a serious issue. I have experienced exactly that on a Ford, engine light, limp mode, key reset no DTC.
The problem is you see, is we don't know if the loss of power is an ecu designed affect or a purely mechanical non ecu problem ie loss of fuel pressure, insufficient air flow etc?
A skilled scanner operative will see what the cause/reason is.

 

[Keith Spencer]

Ps skilled scanner doesn't mean main dealer.

 

[theoneandonly]

If it is a crank sensor then attaching an oscilloscope with back probes and monitoring the signal will show you any changes with temperature and could be quickly ruled out as the cause.
The trouble is we don't have the knowledge to know how the ECU programming team have written the software in Italy. They could have designed it for certain conditions to show an engine light and place the engine in mild limp mode until the ignition key is turned to off for the reset. Many manufacturers do this as a means to protect their engine just in case it's the beginning of a serious issue. I have experienced exactly that on a Ford, engine light, limp mode, key reset no DTC.
The problem is you see, is we don't know if the loss of power is an ecu designed affect or a purely mechanical non ecu problem ie loss of fuel pressure, insufficient air flow etc?
A skilled scanner operative will see what the cause/reason is.

Thanks for an insight to how DTCs are avoided.
I recently aquired a scope and was looking for things to measure whilst in a known "good" state. and also read a few bits and pieces.
There was one article i read about a ducato crank sensor and its mounting position and an intermittant fault, also one with a dodgy wire to connector. this case study was related to a 3.0l engine.

 

[P and A]

Thanks for the help so far. We are taking it to a Fiat dealer on Monday to look at it again. We will suggest some of your ideas.

 

[Keith Spencer]

Thanks for an insight to how DTCs are avoided.
I recently aquired a scope and was looking for things to measure whilst in a known "good" state. and also read a few bits and pieces.
There was one article i read about a ducato crank sensor and its mounting position and an intermittant fault, also one with a dodgy wire to connector. this case study was related to a 3.0l engine.

An ex excellent channel to view on YouTube is Ivan in "pine hollow auto diagnostics" he is very methodical and explains most things. Irrelevant which engine they all operate on similar concepts

 

[Keith Spencer]

We have a 2017 motorhome with a Fiat 2.3 engine. We have a problem that no one can detect what is causing it. After starting the engine and driving for about ten minutes sometimes, not every time, the engine loses power. You can still drive it but it will be slow to accelerate and slows down up a hill. It’s just like the turbo has stopped working. If we stop, turn off the engine and restart it, the problem has gone for the rest of the day, but the engine warning light will stay on, maybe for that day, or the next few days sometimes and then goes off. Other days you can drive it for a week or more and this problem never happens. Has anyone any ideas what is causing it. The problem has happened since nearly new, and we have now done 28,000 miles in the motorhome. Thanks.

Hi p and a again,
Had a long think overnight and I am 99% certain it's an ecu limp mode you are experiencing not a significant mechanical issue, yet!
Couple of questions I need you to reply to me please if you want more direction.
1 was it scanned whilst the engine light was lit?
2 what emission standard is your engine, euro 4, euro 5 or euro 6?
3 on your dash display in the LCD box, bottom left side is the ambient temperature, does it display an accurate temperature or ___C?
Answer these points and I will come back with a further reply.
Thanks Keith
PS I also have a 2009 fiat ducato 2.3 motorhome identical mileage

 

[Keith Spencer]

Thanks for an insight to how DTCs are avoided.
I recently aquired a scope and was looking for things to measure whilst in a known "good" state. and also read a few bits and pieces.
There was one article i read about a ducato crank sensor and its mounting position and an intermittant fault, also one with a dodgy wire to connector. this case study was related to a 3.0l engine.

Hi,
As you are saying it is always difficult to know what the correct oscilloscope display should look like, I believe some very expensive scanners snapon etc do provide known good data catalogues and autodata seems to be a well used reference library for electrical issues.
But if you do have a badly positioned or loose sensor an oscilloscope and wiggle test should find it pretty quick.

 

[theoneandonly]

Hi,
As you are saying it is always difficult to know what the correct oscilloscope display should look like, I believe some very expensive scanners snapon etc do provide known good data catalogues and autodata seems to be a well used reference library for electrical issues.
But if you do have a badly positioned or loose sensor an oscilloscope and wiggle test should find it pretty quick.

Picoscope apparently have an extreamely good library but only if you have one of the expensive automotive scopes. Access is logged/permited based on the device you have attached, so not for the cheapest picoscope ie mine.