Fiat Ducato 2.3 Multijet

[seadog]

Hi all

Just wondered if any technical members can offer assistance. This is an 11 year old van, low mileage regular service and runs fine, however I always get black smoke from the exhaust when accelerating from a junction/roundabout or under heavy load. Went to check the air filter the other day and noticed a small rubber pipe hanging lose. The pipe goes down to, what I think is the EGR valve.

Looking further and with the help of google, it appears the other end of this pipe should be connected to an EGR solenoid valve that is fitted above the engine and seems to have a spare outlet on it. Can anyone explain what this valve does and what effect this disconnected pipe will have

 

Thanks

[rayc]

When it is disconnected the EGR valve will always be closed so exhaust gases cannot be recirculated into the inlet manifold to be burnt off. This assumes the EGR valve is not jammed open in the first place.

https://www.evanshalshaw.com/blog/what-is-an-egr-valve/#:~:text=The%20EGR%20system%20works%20by,system%20and%20it's%20normally%20closed.

[Derek Uzzell]

I notice that “Seadog" asked about this here on 12 October 2018, with expert advice provided by Nick Fisher (euroserv).

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Black-smoke-issue/50455/#M583838

 

On 30 October Seadog 2018 reported that an 'air mass sensor' had been the culprit and the fault had been cured.

 

(It might be useful a) to have some identification details of Seadog’s motorhome and b) to know when the excessive smoking that (apparently) was successfully addressed in 2018 recurred.)

[Brian Kirby]

I hesitate to ask this, but shouldn't "Seadog's" van have been failing its MoTs for the sort of smoke he describes, or is this simply the occurrence of a new fault that, coincidentally, has similar symptoms?

[colin]

The solenoid should have two pipes connected, one provides a vacuum, the other goes to EGR. With one disconnected the EGR won't work.

A few years ago when I had problems with van in France a garage attempted a temporary fix to get us home by blocking one of the pipes as they thought the EGR valve was somehow causing problems but they couldn't fix it. The van seemed to drive pretty much the same with EGR valve working, or not, but I don't recall any black smoke.

[mikefitz]

The small control unit should have the pipe connected. The black smoke is due to the EGR not operating correctly. This results in the air to fuel ratio being incorrect, thus the black smoke in the exhaust. The solenoid valve, controlled by signals from the engine ECU, adjusts the vacuum on the EGR actuator to give various levels of exhaust gas recirculation depending on engine load.

 

Hopefully its just a accidental disconnection but the control unit can fail and will need replacement if this is the case.

 

Note that the throttle body valve that operates in conjunction with EGR can fail on early vans. This may be a contributing factor.

 

Mike

[seadog]

Thanks for the very useful information guys