J@mes wrote:

It didn't work for me!

The glowplugs heat the combustion chamber to very high temperatures in order to aid the burning process, the FBH controller heats the coolant around the engine and makes no difference to the combustion chambers at all.

I initially thought I would get away with using my FBH controller instead of having glowplugs, but it doesn't sort the issue at al

edit: if anything, it probably makes it worse as the glowplug controller thinks the engine is up to temperature when it's not, and therefore doesn't run the plugs for as long!

I find it strange then that the glow plug light does not come on

I though, and it is only a thought that the glow plugs did not fire as a result of the water temperature being high enough for them to think they were /are not needed, a sensor of some sorts?

If that is the case my car starts without glow plugs on a cold morning, so if mine does, the OP's logically would too.

Of course someone will tell me that the glow plugs still have a half cycle or someting that does not involve the dash light coming on but still preheats the combustion chamber.

Conversely my 300TDI defender does not even have them connected , and that also fires up OK, perhaps I'm blessed

Robbie wrote:

Mikey et al,

The D3 glow plugs do a little more than just aid starting and this causes confusion when people use FBH controllers such as the BAS system.

Due to the 'efficient' design of the engine the glow plugs are required to support ignition well after initial start. When the engine is cold compression alone is insufficient to provide complete ignition of the cylinder diesel charge at low revs, so you get lumpy idle, poor pick-up, poor emissions and general roughness. If you rev to above 2000rpm or so the engine become more self sustaining and things smooth out. Once the engine is above about 50 deg C then all is well.

To overcome this the glow plug system enters a lower power 'afterglow' phase shortly after start and the plugs stay 'lit' until the coolant system reaches 50 deg C. To avoid the plugs causing early detonation at higher rpm the afterglow system goes into a quiescent state when above 2500rpm - all values are taken and controlled by the ECM.

The confusion with FBH pre-heating arrises because it artificially increases the coolant temperature above the 50degC limit and effectively disables the afterglow system and reduces the full power time of the plugs ahead of starting. As the engine internals are still pretty cold you can get quite a lumpy start and very rough running to the point that people suspect a serious fault. Once warmed to normal combustion temperatures all is well again.

Like Mikey I have not seen a D3 fail to start (albeit with a little more effort) without glowplugs, well not at typical UK temps. I have however seen them run as rough as hell when the afterglow system fails to do its stuff.

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