The 8140.43 2.8L Diesel engine used in various Fiat Ducato, Peugeot Boxer, Citroen Relay and other vans and MotorHomes uses a fairly unusual cold start system, here we’ll look at how it works so if you need to do any troubleshooting, you know where to start!
Firstly, there are two separate cold start systems, one that advances the diesel injector timing whenever the engine is started from cold, and another ‘Flame Start’ device that operates whenever the ambient temperature is around freezing or lower.
Injection timing advance:-
On the diesel injection pump there is a lever that when actuated advances the diesel injection timing a few degrees. This is because the actual fuel burn when injected is slower in a cold engine so injecting it a little earlier allows more time for a complete burn. The lever is actuated by a ‘wax stat’ type device that is supplied with 12V when the engine is running, as it warms up the wax expands and moves the lever from the advanced timing position back to the normal running position. In the photo below (shown looking up from the bottom of the engine) you can see the wax stat circled in red – the electrical connection is on the left of the unit:-
Because this defaults to the advanced timing position if for example the electrical connection fails the diesel timing will stay at it’s ‘cold’ setting, regardless of engine temperature (in reality you may not even notice this has happened, though it will probably have a negative impact on your fuel economy). Over the course of a few minutes after starting the engine you should see the lever get slowly pulled towards the wax stat if everything is working properly.
Flame Start device:-
This is the more unusual part of the system. This engine does not have glow plugs like most diesel engines (electrical heaters in the cylinders that help ignite the fuel when the engine is cold), instead it has a ‘flame start’ device in the inlet manifold. This is a single heater plug and an additional diesel supply, when it is operating it puts a small amount of fuel on the heater, setting fire to it directly inside the inlet manifold! This was instead of the engine drawing in cold air it the air is pre-heated by the flame starter.
In this picture you can see the device in the top of the inlet manifold (the inlet air hose has been disconnected for clarity):-
The heater plug is the rusty unit in the middle of the photo, with the electrical connection to the top of it. The solenoid that controls the fuel supply is the cylindrical unit lying on top of the inlet manifold, with the electrical connection to it on its left hand end.
Here is a photo looking into the inlet manifold where the air intake hose connects, you can see the end of the flame starter poking into the manifold on the left hand side:-
This is the flame starter, just after the engine has started, you can see the flame starting to build
And here it is a few seconds later, once the flame has properly got going
With this system it is important to not wait until the glow plug light has gone out before starting the engine, as you would with most diesels. Instead turn the ignition on (glow plug light will come on constantly if it is cold enough to need the flame start) and allow a few seconds for the heater plug to heat up, then crank the engine. Once the engine has started the glow plug light will flash while the flame starter is operating, and go out once when the flame starter turns off.
The glow plug light will look like this, it’s in the bottom right of the instrument cluster
Note – this is on an 8140.43 engine with a Bosch VE pump style fuel injection system, if you have the later 8140.43s engine with a common rail injection system I don’t know if they have a flame starter (and the ignition advance is probably done electronically, rather than using the wax stat as mentioned above). If you know whether they have a flame starter or not please let me know in the comments below!
For interest, here is a short video of the flame starter running:-
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