had a 10 year service yesterday, which included a fuel filter and coolant change,

is it possible this could stop my FBH from working?

It was working fine before service no its not ?

I cant hear the clicking from the fuel pump at the rear like before

daz Regards

Daz

-------------------------
2011 (61plate) 4.4 tdv8
sumatra black

previous cars

e46 m3
e53 x5

Are you sure that today was cold enough?

Since the weekend storm the temperature has been above the FBH trigger (6-7°C). L322 3.6 TDV8 Vogue. 07MY
ML 320 7 Seat full leather etc. (The Black Pearl)

Daz

Are you talking aobut the FBH not running when you use the remote for park heating or simply when the engine starts to provide a quicker warm up of the engine?

If the temperature is above 8c then the unit does not work for engine heating, but below 16c it works for park heating IIRC.

AND, have you over 1/4 tank of fuel?? Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT

Hmm got me going now lol.

I managed to get it working in the end by forcing it to restart about 4 times just by keep turning it on via the key fob remote.

I wonder if after the fuel filter change there was some air which needed purging ?

It fired up after the 4th ish time of turning it on. Even though it was already running (but not pumping fuel) Regards

Daz

-------------------------
2011 (61plate) 4.4 tdv8
sumatra black

previous cars

e46 m3
e53 x5

Last edited by dazza1983 on 15th Feb 2020 3:16pm. Edited 1 time in total

Daz

The FBH fuel pump simply draws fuel directly from the tank via its own suction line, which sits low down in the offisde section, held in place by locating pieces on the main in tank pump. The only filter I can see for it is the mesh fitler insert in the FBH pump itself. Changing the main fuel system should have no efffect on the FBH.

There are some threads about the FBH having diffuculty firing due to carboning up, the igniter not working correctly and the water pump being suspect. The unit can be removed from the car and worked on if you feel like it.

Have a read through the WM section on climate/auxilliary heater. Be prepared for a long read, say an evening with a glass of something friendly at your side.

Oh, and don't forget the battery voltage is critical for the FBH. It shuts down if it falls bellow a certain value, Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT

I wonder if the coolant change may have had any effect on it then?

Daz

Just seems weird lol. I’ve done my fair share of research on the fbh and feel like I’m fairly up together on how everything works.

I still think that the battery is well over protective on how much charge it needs for it to fire up.

Oh and the common misconception that it won’t fire above 5 degrees when in fact it’s around the 13 degree mark. Regards

Daz

-------------------------
2011 (61plate) 4.4 tdv8
sumatra black

previous cars

e46 m3
e53 x5

I would have thought a coolant change/problems would lead to an airlock perhaps, or the changeover valve sticking. I'd have to assume either would allow the FBH to fire up but be shutdown by overheat protection in its water jacket.

On temperature for firing up in additional heat mode, I can only go with the WM which says it does if these parameters are met:

The ATC module activates the additional heating mode when the engine is running and the following conditions coexist:
The ambient temperature is less than 1 °C (34 °F) on petrol vehicles or 8 °C (41 °F) on diesel vehicles.
The engine coolant temperature is less than 75 °C (167 °F).
The heater coolant temperature is less than 70 °C (158 °F).
The heat demand is more then 75%.
The blower is on.

Park heating is available on demand below 16C but above -20C on diesels:

If the ambient temperature is less than 16 °C (61 °F) and, on diesel models, more than -20 °C (-4 °F), the ATC
module initiates parked heating and:
- Energizes the changeover valve.
- Sends a K bus message to activate the FFBH.
- Operates the blower at 47% of the maximum speed.
- Operates the distribution doors in the heater assembly to direct the air to the footwells for approximately 30
seconds, then to either only the windscreen, or to both the footwells and the windscreen, depending on the
ambient air temperature.
- Flashes the auto blower LED at 2 Hz.
- On diesel models, if the ambient temperature is -20 °C (-4 °F) or below, the ATC module sends a K bus
message to activate the FFBH, but leaves the changeover valve de-energized and does not operate the blower or
distribution doors. Heated coolant is circulated around the engine and heater core(s) to heat the engine and
improve engine starting.


B****y complex and hot coals on a shovel under engine and fuel tank would work, but then you'd have to employ a stoker overnight  Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT