Ducato Cold Start / Flame Start system explained

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!

UPDATE! – Alan (a Motor-roam visitor) has been in touch to say his 2006 8140.43s 2.8l JTD (common rail) engine also has the flame start device – many thanks Alan!

For interest, here is a short video of the flame starter running:-

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  1. My 2006, 8140.43s, 2.8 JTD engine does have a flame start device.

  2. Hi, i have a 2005 (55 plate) Ducato 2.8JTD with flame start and upon ignition the Glow plug light will go on but only for a couple of seconds , it has never flashed, is this correct? I have had the flow plug renewed recently and having difficulty starting in cold conditions recently (will start with a bit of cold start in the airways) thanks

    • Dan

      December 4, 2019 at 6:20 pm

      Hi Paul, if you system is the same as mine the light will only start flashing once the engine has started, and if your light is going out after a couple of seconds it sounds like the engine is not trying to run the flame starter. It may be the ambient temp is not cold enough (it needs to be near freezing or below) or the temp sensor is faulty so the engine thinks it is warmer than it actually is. With the intake air pipe removed you should be able to observe if the flame starter is trying to do anything.
      Also, as the flame starter is more to speed warm up than actually help starting it may be you have an issue with the cold start fuelling, or in-cylinder glow plugs (if the JTD has these?)
      Hope this helps, let us know what you find and just shout if you have any other questions! Cheers, Dan

  3. Hi Dan, this is brilliant explanation of how both cold start systems operate and are fitted to my 1995 Ducato motorhome. My engine is worn and during cold weather takes longer to start putting more strain on my battery. The problem with the flame starter is that it will not operate until it is below freezing. I have read much about bypassing the temperature sensor/relay and wiring the plug directly to a push button on the dash. I think this would be great on the cold but not freezing days but how would it power the fuel solenoid and how would I wire it?
    I would value your comments and recommendations.

    • Dan

      February 3, 2020 at 6:54 pm

      Hi Chris – thanks for the comment! πŸ™‚
      If you are having trouble starting in cold weather I’m not sure hot-wiring the flame starter would help much, as it doesn’t really do anything until the engine has actually started (it’s more for helping warm-up than actual starting). I would look first at your fuel system, particularly injection timing, and perhaps get the injectors checked/cleaned?.
      If you do want to hot-wire the flame starter then I would take a fused feed directly from Batt+ and use a high power relay to switch it to both the fuel solenoid and the glow plug, and control the relay from a switch on the dash (you are unlikely to find a dash mount switch/button that could handle the required current directly). You could get fancy and incorporate a timer circuit, so you don’t forget and leave it running continuously!.
      Hope this helps – let us know how you get on! Cheers, Dan

      • Thanks Dan,
        Thanks for that, I’m off to Spain tomorrow in my van for the rest of the winter (slightly delayed this year) but on my return will do some work on my engine, while I’m away I will try the direct wiring to see if it helps on the cold parts of the journey. I will let you know how I get on πŸ™‚

  4. Hi Dan,
    -2 this morning so thought I’d try the cold start. Ignition on, cold start light solid, waited for about 12 secs light started blinking and could hear fuel solenoid firing after couple of secs cranked it over and hey presto, it started just like it’s supposed to. light continued to flash for about 8 secs then went off, brilliant!
    Now, my next question is, as this is all working, what detects the temperature and sets off the procedure and can I do something to bypass it, or fool it into thinking it is below zero so I could use the system manually when its a few degrees above zero? That would be more effective that wiring the plug and fuel solenoid directly as there is clearly a timing issue here with the solenoid continuing to pump the fuel after it’s started for a few seconds. It would be great to have a manual control if possible. Thanks for your help

    • Dan

      February 6, 2020 at 7:26 pm

      Hi Chris – there will be a temperature sensor located in the cylinder head somewhere – I don’t know where exactly on this engine but you should be able to trace the wiring back to it. It is likely to be a single wire resistive/PTC sensor. If you wanted to modify the behaviour you could characterise the sensor by measuring the resistance of the sensor to earth with the engine cold and again with it hot – the temperature/resistance plot is roughly a straight line between these points (if you can measure the resistance at a few different temperatures even better, as it’s likely to be a curve rather than a dead straight line). You can then modify the sensor with additional resistance in series (if you want to increase the resistance) or resistance in parallel (if you want to decrease the resistance). This should adjust the operating temperature of the flame start (you could even put a variable resistor in to allow you to change the behaviour with a dial). Note: If you have any electronic diesel controls on your engine the sensor may also be used for these, but if it’s a simple mechanical fuel injection the temp sensor is unlikely to be used for anything else other than the dash display. Hope this helps – Keep us posted! Cheers, Dan

      • Hi Dan, that’s just the information and explanation I was looking for. I will have a play and see how I get on over the next few weeks while I’m away. I’ll let you know what happens.
        Thanks again for the detailed info

  5. My 93 Ducato has this system
    Is there anything on my ducato that helps it actualy start when cold ? Only asking as seems to struggle to start, it’s been sitting for year , I only run it around around the block now and then.
    Used to start on the button.
    Battery is good.

    • Dan

      February 6, 2020 at 9:34 pm

      Hi Paul – depending on engine variant you have probably got a cold start injection advance wax-stat on the injection pump and/or glow plugs. Glow plugs are the main thing that will effect cold starting, they should be powered at ignition on for a short time and should heat up quickly. It’s worth checking they all get power and that non of them have failed open circuit or high resistance (you can check this with a multimeter). Hope this helps, Cheers, Dan

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