Technical High pressure fuel issues

[STEVE ROB]

Hi can someone please help me interpret this l have been to 2 different garages with no joy
My fiat doblo 1.3 multijet take about 4/5 goods goes at starting before it starts and then runs fine however it periodically has the engine fault light come on with the script check engine.
it will stat within a meter on a hill start ...not sure if that's relevant
Thanks Steve

 

[bugsymike]

Can your diagnostics read common rail fuel pressure on cranking if below roughly 230Bar that maybe an issue, possibly do a leak off test to see if injectors worn.

 

[STEVE ROB]

Can your diagnostics read common rail fuel pressure on cranking if below roughly 230Bar that maybe an issue, possibly do a leak off test to see if injectors worn.

Hi thanks for taking time to answer. Sadly no it doesn't however l did have new injectors and heat plugs before Christmas and apart from starting it runs fine

 

[bugsymike]

Hi thanks for taking time to answer. Sadly no it doesn't however l did have new injectors and heat plugs before Christmas and apart from starting it runs fine

Pity about the diagnostics, it may have given a better idea.
Is the vehicle high mileage? If compressions are not as good as when new. Diesel engines other name is CI or compression ignition engines, so if compression not ideal then the air doesn't get hot enough to ignite the fuel easily. Usually worse on cold winter days and if battery/ starter not spinning engine quickly.
Just thinking if needed heater plugs replacing was there any white smoke on cold starts, that can be a pointer sometimes smelling of unburnt fuel.
Once warm engine is usually great for the rest of the day. The bump starting on a hill may be a pointer.
Sorry if trying to "teach granny to suck eggs" there is often a wide variation of knowledge on the Forum.

 

[STEVE ROB]

Pity about the diagnostics, it may have given a better idea.
Is the vehicle high mileage? If compressions are not as good as when new. Diesel engines other name is CI or compression ignition engines, so if compression not ideal then the air doesn't get hot enough to ignite the fuel easily. Usually worse on cold winter days and if battery/ starter not spinning engine quickly.
Just thinking if needed heater plugs replacing was there any white smoke on cold starts, that can be a pointer sometimes smelling of unburnt fuel.
Once warm engine is usually great for the rest of the day. The bump starting on a hill may be a pointer.
Sorry if trying to "teach granny to suck eggs" there is often a wide variation of knowledge on the Forum.

Hi thanks thanks for any advice l actually live in Spain so it's warm at the moment and once running yes it's fine but it alway take an age to restart if l stop anywhere even if its for a minute

 

[bugsymike]

Hi thanks thanks for any advice l actually live in Spain so it's warm at the moment and once running yes it's fine but it alway take an age to restart if l stop anywhere even if its for a minute

Is there a good fuel supply?

 

[STEVE ROB]

Is there a good fuel supply?

How's the best way to check ?

 

[bugsymike]

How's the best way to check ?

Assuming you have a working fuel pump in the fuel tank, then take the outlet pipe off the fuel filter and run it into a container, have someone switch ignition on and see if good flow. Note if engine not running the flow only runs for a short while for safety reasons.
If poor or no flow it can be blocked filter under bonnet or blocked filter around fuel sensor/pump in tank.
Or another is a faulty fuel relay to power the fuel pump in the tank.
On an older Doblo that relied on the high pressure pump to draw the fuel from the tank, I got it running with a jury rigged tank on the wing which allowed me to prove a leaking fuel line.
It can be a process of elimination if you don't have access to good diagnostics.

 

[varesecrazy]

How's the best way to check ?

When you turn the key,

How long does the pump in the tank run?

 

[STEVE ROB]

Assuming you have a working fuel pump in the fuel tank, then take the outlet pipe off the fuel filter and run it into a container, have someone switch ignition on and see if good flow. Note if engine not running the flow only runs for a short while for safety reasons.
If poor or no flow it can be blocked filter under bonnet or blocked filter around fuel sensor/pump in tank.
Or another is a faulty fuel relay to power the fuel pump in the tank.
On an older Doblo that relied on the high pressure pump to draw the fuel from the tank, I got it running with a jury rigged tank on the wing which allowed me to prove a leaking fuel line.
It can be a process of elimination if you don't have access to good diagnostics.

Thank you so much will give it a go this morning

 

[STEVE ROB]

Thank you so much will give it a go this morning

Hi thanks tried it this morning l disconnected at the top of the pump and when the ignition is switched on a good slug of fuel come out .

 

[bugsymike]

Hi thanks tried it this morning l disconnected at the top of the pump and when the ignition is switched on a good slug of fuel come out .

That's one thing off the list.
Pity you can't get a cranking pressure figure from the diagnostics.
Are the injector just s/h or reconditioned etc. If suspicious a "leak Off test" may show up a suspect injectot.

 

[STEVE ROB]

That's one thing off the list.
Pity you can't get a cranking pressure figure from the diagnostics.
Are the injector just s/h or reconditioned etc. If suspicious a "leak Off test" may show up a suspect injectot.

Hi Update a friend called round yesterday and said, ( once l got it running) that it sounded like the timing chain was out as it sounded rough ( l hadn't noticed as l was always inside) and he said maybe that's why the high pressure fuel pump is misaligned/ needs adjustment as in diagnostic.....does that sound feasible?

 

[irc]

Were the injectors codes updated in the ECU when replaced?
Can sometimes cause rough running or starting problems on the 1.3 multijet.

 

[g8rpi]

Hi Update a friend called round yesterday and said, ( once l got it running) that it sounded like the timing chain was out as it sounded rough ( l hadn't noticed as l was always inside) and he said maybe that's why the high pressure fuel pump is misaligned/ needs adjustment as in diagnostic.....does that sound feasible?

Not that. The multiet is common rail electronic injection. The fuel pump isn't timed.

Why wher the injectors changed? Did the symptoms change when they were replaced.
A copy of MES and an a interface will allow pressures to be monitored and would be a better investment than buying parts without evidence.

That said, the hill start bing OK is a big clue. I think the issue is voltage related. More specifically voltage changes caused by the starter motor current during cranking. This could be a voltage drop but there ais also a possibility of "ground bounce" where there is a difference in voltage between the common or ground connection of different parts. In particualr sensors on the engine block and the ECU. The current from the starter can cause the sensor "ground" to rise in voltage causing a false signal.
The root cause of this is a bad earth connection either between the engine block and Chassis or between battery negative and Chassis.
Get a pair of jump leads. Connect one between engine block and Chassis and the other between battery negative and Chassis (or block). If that fixes it bet new ground leads.

Robert.

 

[bugsymike]

Hi Update a friend called round yesterday and said, ( once l got it running) that it sounded like the timing chain was out as it sounded rough ( l hadn't noticed as l was always inside) and he said maybe that's why the high pressure fuel pump is misaligned/ needs adjustment as in diagnostic.....does that sound feasible?

When I did my daughters 06 Grande Punto 1.3 Multijet including head off and new timing chain kit etc. using the correct timing tools, the high pressure fuel pump was just bolted on, no adjustment necessary.
The critical thing is to set the timing using the tools and making sure the new guides and chain are fitted correctly.
As @irc mentions injector code updating is recommended for a smoother running engine and may improve starting, but in all honesty I have never re coded injectors even after stripping and rebuilding with new pintles etc. or mix and matching second hand ones and they all ran clean and smooth for Mot test etc.
You are not getting any spitting noises as in poorly seating injectors in cylinder head are you? I made a point of re cutting the injector seats before fitting with new copper washers etc. as they are a weak point on this model due to one little clamp used to hold down two injectors.