Technical Engine stumbles runs rough, Ducato 2008 2.3 multijet diesel

[Ducatoghosts]

Hi everyone, I'm hoping somebody can offer some advice as I'm at my wits end trying to solve the problems I'm having with my Ducato 2.3 multijet diesel. Here is the problems I'm having:

The vehicle starts every time on the key. But It runs rough, stumbles and stutters to rev has an intermittent knock (thought it could be a injector knock.. not convinced now)
When warming up its a slight improvement but Acrid exhaust and slightly smoky would say it's white with a hint of blue. Not dense.
Cannot be driven as the engine surges
The vehicle has only done 30k miles

Items already replaced are:

Maf
ECU tested and rebuilt
New injectors coded to ECU but new ones are 8 digit and ECU only accepts 7 digits.
New fuel filter including canister
Fuel tank drained and filled with new fuel
New cam sensor
The throttle body was replaced 1 year prior to this fault for the new upgraded item.
Egr cleaned and tested
New egr control solenoid
New brake booster vacuum pipe ( t's off for the egr solenoid replaced incase there was a blockage)
All lines checked for splits, deterioration etc
Turbo checked (clean no play and spins freely)
Timing belt checked and timing marks all line up.
Timing chain Inc tensioner are in excellent condition and no play.

Pcv valve on order as old ones diaphragm has gone soft and swollen.


I would like to understand the readings from MES I don't know if for example 69% egr at idle and 80 Deg c temp is correct
While the throttle opening varies from say 79% up to 86%

Injector readings what should they be at idle?

 

[Ducatoghosts]

Once it warms up a bit it revs pretty cleanly. And sounds smooth with the occasional stumble. But back on idle it is lumpy

 

[Kahcorp]

@Ducatoghosts
Definitely sounds like vacuum leak causing stumbles & smell.
Boost Solenoid problem leaking to atmosphere??
Block off each vac line at idle & see if there is a change.

 

[Ducatoghosts]

@Ducatoghosts
Definitely sounds like vacuum leak causing stumbles & smell.
Boost Solenoid problem leaking to atmosphere??
Block off each vac line at idle & see if there is a change.

I will go back through the lines. Thank you for your reply.

 

[bugsymike]

I will go back through the lines. Thank you for your reply.

Just a thought, does your Diagnostic tool read the "cinder count" and pressure sensor readings of the DPF (if applicable on your model), is the engine trying to do a Regen?
Another thought along that line is I know Fiat had an issue with DPF pressure sensors going faulty, to the the point that an old Fiat mechanic I know said it was one of the first things they used to check out.
Presumably with the very low mileage for the year it hasn't had much opportunity to get the DPF hot long enough to give it's self a good clean out.
Incidentally if badly blocked it can cause Turbo failure, so worth checking.
I bought a very high mileage Citroen which ran badly with clouds of very foul smelling white smoke.
I tried all the EGR route stuff and finally removed and thoroughly cleaned the DPF then borrowed my mates Snap On tool to tell the ECU that the DPF had been replaced, deleted all the error codes and gave it a good run. After that it was reliable for another four years before I finally fitted a new DPF.

 

[Ducatoghosts]

Just a thought, does your Diagnostic tool read the "cinder count" and pressure sensor readings of the DPF (if applicable on your model), is the engine trying to do a Regen?
Another thought along that line is I know Fiat had an issue with DPF pressure sensors going faulty, to the the point that an old Fiat mechanic I know said it was one of the first things they used to check out.
Presumably with the very low mileage for the year it hasn't had much opportunity to get the DPF hot long enough to give it's self a good clean out.
Incidentally if badly blocked it can cause Turbo failure, so worth checking.
I bought a very high mileage Citroen which ran badly with clouds of very foul smelling white smoke.
I tried all the EGR route stuff and finally removed and thoroughly cleaned the DPF then borrowed my mates Snap On tool to tell the ECU that the DPF had been replaced, deleted all the error codes and gave it a good run. After that it was reliable for another four years before I finally fitted a new DPF.

Thank you for your reply. This model doesn't have a dpf. I have MES diagnostics I'm not sure if the readings I'm getting are correct as I don't have the parameters they should be at to compare. No ECU fault codes are showing up.

 

[bugsymike]

Thank you for your reply. This model doesn't have a dpf. I have MES diagnostics I'm not sure if the readings I'm getting are correct as I don't have the parameters they should be at to compare. No ECU fault codes are showing up.

Does the white smoke smell of diesel/unburnt fuel when cold.
Any loss of coolant, antifreeze in combustion chamber can give white smoke, but usually smells sweet.
Both of these issues go when engine warm, so maybe irrelevant.
Surging strange when trying to road test, no chance air getting into system?
Are you able to read common rail fuel pressure from start up and as you rev engine?
I had a 2010 2.0 Fiat Scudo that gave erratic pressure readings and engine rattles, traced that fault to the injector pump drive from camshaft end, fitted new cam to cure that.
Have you a really good Diagnostics company down your way that the Motor Trade uses, we have one here, trade complains about the price, but he finds the fault when they cannot with their diagnostic tools.

 

[Ducatoghosts]

Does the white smoke smell of diesel/unburnt fuel when cold.
Any loss of coolant, antifreeze in combustion chamber can give white smoke, but usually smells sweet.
Both of these issues go when engine warm, so maybe irrelevant.
Surging strange when trying to road test, no chance air getting into system?
Are you able to read common rail fuel pressure from start up and as you rev engine?
I had a 2010 2.0 Fiat Scudo that gave erratic pressure readings and engine rattles, traced that fault to the injector pump drive from camshaft end, fitted new cam to cure that.
Have you a really good Diagnostics company down your way that the Motor Trade uses, we have one here, trade complains about the price, but he finds the fault when they cannot with their diagnostic tools.

Where the vehicle is located I have had multiple "diesel specialists" look at it. This has caused me to Spend a lot of money on the parts cannon to no improvement. Lost a lot of faith in claimed specialists. When I get chance to go back to it, I will check out your suggestions. Thank you.

 

[bugsymike]

Where the vehicle is located I have had multiple "diesel specialists" look at it. This has caused me to Spend a lot of money on the parts cannon to no improvement. Lost a lot of faith in claimed specialists. When I get chance to go back to it, I will check out your suggestions. Thank you.

I understand your thoughts on that, the one I was referring to is extremely professional and as I mentioned, the trade go to him when they have tried everything else.

 

[Communicator]

I will go back through the lines. Thank you for your reply.

In case it helps, I have a memory from browsing a recent thread where a damaged vacuum line was discovered. The damage was where the pipe had rubbed against the bodywork, and was only discovered when the poster ran his fingere behind the pipe.

 

[Ducatoghosts]

When I get a minute I will post up my graphs from mes, if any

In case it helps, I have a memory from browsing a recent thread where a damaged vacuum line was discovered. The damage was where the pipe had rubbed against the bodywork, and was only discovered when the poster ran his fingere behind the pipe.

Thank you for your reply. I will go through all the vacuum pipes

 

[Ducatoghosts]

UPDATE: i have been back to the ducato this weekend to go through the items advised, i could not find any bad vacuum pipes. egr functioning (can see it moving at the back of the engine, i even went as far as to remove the entire ecu engine loom and test continuity to each sensor and injector plug to eliminate any broken wires in it.

i have some MES graphs. first one is idle, showing throttle body ,Egr and rpm output. it shows how irregular the idle is, strange thing is after a while the egr smooths out and the throttle still jumps about. this is the updated throttle body which was fitted in 2023

second graph shows the readings with the throttle body disconnected at idle then i raised the revs.

can anybody have a look at the graphs and advise?

 

[Ducatoghosts]

this is the injector fueling graph (pilot, pre and main)

 

[AsdaPricey]

Hello @Ducatoghosts

You must be frustrated by now.

When I first took on my own 2008 but 3.0 Ducato X250 it suffered a myriad of problems including an intermittent hesitant throttle & erratic idle and a fair bit of grey - so not identical but not dissimilar.

Amongst the many many things I did before eventually curing it were;
1) Replaced boost solenoid and a portion of the vacuum line from Egr. This had a profound effect on the erratic idle. I plugged the vacuum line to the EGR at the boost valve and the idle significantly changed. A check with a vac gauge showed the line to the EGR initially held vacuum but quickly leaked off. Replacement line cured this.

2) Cleaned all, and I mean all fuse board and ecu connections - this is tedious but a worthwhile exercise - its all very well having continuity in a circuit but if there’s a voltage drop or current deficiency due to verdigris or a poor connection, the system cannot function properly.

3) adding two new earth leads (one in battery box + one in extra in engine bay) & replaced existing braided lead - just to ensure that components weren’t being current starved.

You mentioned a new throttle body - is that performing as expected - or is the butterfly flap doing its own dance at idle?

Sadly I don’t have any answers for your problem but perhaps you could re-check powers and grounds and perform a vacuum test of the EGR circuit with a basic handheld vacuum gauge.

Before posting this reply I have just re-read back through your work conducted - you don’t mention checking for boost pipe leaks - are you content there isn’t one?