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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UPDATE – see comment here for info on a readers manual control solution for the flame start system – thanks Patrick! πŸ™‚


  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

  6. Patrick Holland

    May 4, 2020 at 9:22 pm

    Thanks for the excellent explanation Dan. I have a 1992 Fiat 2.5TD. It has the 8140.27 diesel engine. The 2.8 is also an 8140. Varaint. My relay unit broke some time back and I could not source another one. I drew a wire from the +ve at the inition to a push button in the dash and then into the gate of the transistor connecting the flame plug and slenoid to the battery. There is no feedback or timer doing it this way. My engine stuggles to start at lower than 6C without the glowplug. It works well except the glow plugs can burn out very easily. Initially I had a toggle switch and left it on. Bad. Now I press the push button at the same time as I crank the engine for no longer than about 5 seconds. Repeat if necessay. Thanks for showing the wax advance. I will check if mine’s working properly. This might help with smokingbwhen cold.

  7. Hi, Excellent article and has shed some light on cold start smoking issue that has plagued my 2000 Renault Master 2.8td.
    Wax stat for timing advance was inoperative, and the advance lever was in it’s relaxed state (wax stat actuator extended). I replaced the wax stat and there was no change. Upon testing the new stat the center pin pushes out of the device as it warms up. I stripped the actuator housing and the springs had worn the housing causing it to stick. Polished housing, freed up, greased and refitted…all ok!
    Advance lever is now held towards the actuator when cold and before starting. Upon starting (12v present) the wax actuator extends releasing the advance lever into it’s natural state away from the actuator (towards cam belt side of motor). Engine now starts clean and smoth but smokes (unburnt fuel) and misses as wax stat warms up and extends, until engine is warm.
    Your article says “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” which is opposite to what I have, as mine pushes out, releasing the lever.
    Pls can you confirm what is the cold and hot positions for the timing advance lever. Should the wax actuator have 12v permanently (Ign+) applied (doesn’t seem logical for the life of the unit, when it could only actuate in cold temps), or should it only be when ambient temp is cold. Mine has 12v permanently, but trying to work out if relay has welded closed. Do you know where relays are situated or what controls it. I can’t find a wiring diagram of how it it wired.
    Want to get to the bottom of this cold smoking issue. Thanks in advance.

    • Dan

      May 7, 2020 at 6:53 pm

      Hi Alister – I just filmed a 20min video to the wax start during engine start & warm-up (and cool down afterwards) to try and clarify the operation – only to discover that since I last checked my wax-stat has ceased operating! I have however gone back over some old notes and it appears you are correct regarding the direction of actuation, at least on some variants (the actuator should be retracted when cold and extend as it warms up, on some info I found for this engine in an Iveco Daily), Looking at mine however the lever on the pump is clearly pulled by the actuator, with a spring to return it to its rest position – the plot thickens!
      My issue appears to be a lack of power to the wax stat (note I believe it should be D+ rather than IGN, so only live when the engine is running), so there is either something wrong with my wiring or there is some additional control I’m not aware of (my understanding was it is simply a permanent supply from the alternator D+ terminal without any additional control). I’ll do some investigation and report back if I find anything. Cheers, Dan

      • I’ll double check mine to see if it is indeed ign+, or D+ with engine running.
        Mine appears to be working ok now, just warming up and moving the actuator before the engine appears ready for it, causing it to smoke and miss until engine has warmed up properly. I may fit a switch inline with the wax stat live to interupt supply until the engine is a bit warmer before switching back over.
        New wax stat for mine came from ebay https://www.ebay.co.uk/itm/254194498170.
        Bosch part number 1 467 202 320, same part for 2.5td and 2.8td.
        Would still be nice to know what state the actuator arm SHOULD be in hot and cold states, as we seem to have 2 engines working completely opposite to each other.
        I’ll keep searching for a wiring diagram in the meantime.

        • Dan

          May 8, 2020 at 4:25 pm

          Hi Alister – It’s interesting to hear how much of an impact the cold start timing advance has on the running of your engine – on mine it is unnoticeable whether the system is working or not! (I had the van for about a year before I discovered the wire had fallen off the actuator. I repaired it and watched the wax-stat move the lever as the engine warms up, but it made no noticable difference to the engine starting or warm up performance, it was fine in either state!)
          I’ll do some more digging and report back if I find anything….
          Cheers, Dan

          • For reference I checked the feed to the wax stat and it is an ignition live and not a D+ live. Still unsure if there is supposed to temperature controlled or not though.

  8. hi there work allot with the Sofim engines from early 90s through to about 2010 at present, and yes all of the common rail variants i have seen still have flame start, and the advance and such is done in the program, and i was told that on the common rail engines that the cold start operates at a much lower temperature to the mechanical injection, this is mainly because of the gains of direct injection over the indirect injection the mechanical system had to use to overcome diesel knock

  9. Hi! My ducato 1995 based hymer has this system. Im new to the motor and it seems there is an aftermarket button on the dash connected to this system. When I press the button when the engine is off I can hear voltage running to the solenoid area. What might this button be doing and how should I use it? Many thanks

    • Dan

      July 16, 2020 at 11:28 am

      Hi Josh – I can imagine two reasons there might be an aftermarket button wired into the system:- 1) The automatic control has stopped working so someone has added a manual button to activate the flame start when required 2) Someone wanted to either start the flame start before cranking the engine, or leave it running longer once the engine has started so has added the button to over-ride the control. (Both of these are just guesses πŸ™‚ )
      Does the system work OK without needing to use the button on the dash? (note: you will have to wait until it’s near freezing or below to test it!)
      Cheers, Dan

      • Hey Dan, thanks for the speedy response!

        Unless the temp outside is warm, the engine can take a few seconds to get going. Even on a cool summer morning. When the temp outside is roasting like the heatwave we had a few weeks back it would start on the first turn. I have tried pressing and holding the button for a few seconds before starting it up but it didn’t make a difference, not too sure when I should be pressing it or holding it.

        It’s my first van so getting used to everything, it might be that the system itself has a fault.

        Cheers Josh

        • Dan

          July 16, 2020 at 11:49 am

          Hi Josh – no worries πŸ™‚
          The engine shouldn’t need the flame start to get going unless it’s REALLY cold, so I suspect there is something else causing your starting problem. Does your engine have glow-plugs? – if so these would be the first thing I would look at. They should all get +12V when the ignition is turned on, and you should be able to feel them warm up if you leave the ignition on for ~30secs without cranking the engine. You could also use a multimeter to measure the resistance between the terminal and the body of each glow plug, any that are open-circuit suggest a failed plug. Hope this helps, Cheers, Dan

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