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FBH dosing pump and wiring
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Dazz360
 


Member Since: 03 Sep 2016
Location: West Mids Walsall
Posts: 871

United Kingdom 2005 Discovery 3 TDV6 HSE Auto Bonatti GreyDiscovery 3
FBH dosing pump and wiring

Hi guys my heater won’t fire up because the pump isn’t working.
It starts up the coolant pump runs and because it doesn’t fire in shuts off

I’ve taken the dosing pump off and put 12v direct to it and hear the solinoid click once, now I don’t know if the pump should run continues or if the voltage should be a pulse feeding the pump.

I’ve tried also looking for a fuse that may have popped so stopping the voltage to the pump ??
I’m stumped and need advice specially on the wiring where it goes so I can check continuity

Thanks in advance as it’s starting to Censored me off a bit now
 Metal auto sump & fluid change (3 hrs)
LR door puddle projectors (10 mins)
Tinted Bonnet wind deflector (10 mins)
All Intercooler pipes and Tbolts (2hrs)
3 injectors replaced so far (30mins)
Sunroof drain pipes both sides 2.5 hrs)
Rear discs, shoes,pads,callipers,flexi hoses, rigid brake line, n/s upper hub carrier bush and rear n/s upper arm (13hrs over 2 days) 
 
Post #18752222nd Nov 2017 11:56 pm
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discoteca
 


Member Since: 08 Mar 2010
Location: Warwickshire
Posts: 1477

United Kingdom 2016 Discovery 4 3.0 SDV6 SE Tech Auto Corris GreyDiscovery 4

I'm sure it's a PWM pulse input rather than a constant 12v so your test of applying direct 12v won't help.
  
Post #18752273rd Nov 2017 12:06 am
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Martin
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Member Since: 06 Nov 2004
Location: Hook Norton
Posts: 18440

United Kingdom 2006 Discovery 3 TDV6 SE Manual Buckingham BlueDiscovery 3

You may have a blocked fuel line between the pump and the FBH or the tank and the FBH (usually the latter) or duff wiring to the pump.

You can normally hear the pump ticking away when the FBH runs, especially as you know where it is.

Plug the pump back in, then take the FBH 8 pin plug off and apply 12V on and off to pin 5 of the plug. If the pump ticks then the wiring is ok.

If this is the case, remove the fuel line at the FBH and both ends of the pump. With a compressor blow out the line to the tank (you should hear bubbles) and from the FBH back to the pump (just to check it is clear).

Bear in mind if you don't have diagnostics or Webasto software that the FBH will quickly lock itself out due to non-starts.

Martin
 06 D3 SE / 15 LR D90 XS SW / 88 LR 90 Td5 / 68 BMW 2000 ti
Any issues with the site let me know! 
 
Post #18752463rd Nov 2017 6:49 am
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Dazz360
 


Member Since: 03 Sep 2016
Location: West Mids Walsall
Posts: 871

United Kingdom 2005 Discovery 3 TDV6 HSE Auto Bonatti GreyDiscovery 3

Thanks Martin I’ve tried the fuel pipes , the FBH to pump is clear and I can hear bubbles in the tank of the one taking fuel from tank to pump.

I’ve tried applying 12v to the pump and yeah I can hear the solinoid throw one way, it’s the original one so got a new one ordered of flea bay. Should I be able to blow air through the pump or is a one way valve in there ?

Also the wires to the pump, where do they go too ? I’d like to check for a break in the wire just to take them out of the list
 Metal auto sump & fluid change (3 hrs)
LR door puddle projectors (10 mins)
Tinted Bonnet wind deflector (10 mins)
All Intercooler pipes and Tbolts (2hrs)
3 injectors replaced so far (30mins)
Sunroof drain pipes both sides 2.5 hrs)
Rear discs, shoes,pads,callipers,flexi hoses, rigid brake line, n/s upper hub carrier bush and rear n/s upper arm (13hrs over 2 days) 
 
Post #18752753rd Nov 2017 8:41 am
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Martin
Site Admin and Owner 


Member Since: 06 Nov 2004
Location: Hook Norton
Posts: 18440

United Kingdom 2006 Discovery 3 TDV6 SE Manual Buckingham BlueDiscovery 3

I'm not sure exactly how the wire runs in the loom, but do the pin 5 check as above. Or check continuity from pin 5 of the FBH connector to the blue/white wire at the pump connector.

Also continuity to a known good ground (chassis) from the black wire at the pump.
 06 D3 SE / 15 LR D90 XS SW / 88 LR 90 Td5 / 68 BMW 2000 ti
Any issues with the site let me know! 
 
Post #18752783rd Nov 2017 8:44 am
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Dazz360
 


Member Since: 03 Sep 2016
Location: West Mids Walsall
Posts: 871

United Kingdom 2005 Discovery 3 TDV6 HSE Auto Bonatti GreyDiscovery 3

Thanks Martin , will get back with the results
 Metal auto sump & fluid change (3 hrs)
LR door puddle projectors (10 mins)
Tinted Bonnet wind deflector (10 mins)
All Intercooler pipes and Tbolts (2hrs)
3 injectors replaced so far (30mins)
Sunroof drain pipes both sides 2.5 hrs)
Rear discs, shoes,pads,callipers,flexi hoses, rigid brake line, n/s upper hub carrier bush and rear n/s upper arm (13hrs over 2 days) 
 
Post #18753093rd Nov 2017 12:08 pm
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Dazz360
 


Member Since: 03 Sep 2016
Location: West Mids Walsall
Posts: 871

United Kingdom 2005 Discovery 3 TDV6 HSE Auto Bonatti GreyDiscovery 3

Right, new pump fitted and I’ve checked the No 5 wire by putting 12v and listening for the pump to click and it does so. Tried firing up the burner and it starts up all ok but the fuel pump still isn’t doing anything. FBH then shuts down 🤔 I’m stumped
Any advice please.
Does the FBH give the pulse voltage to the pump ? Am I missing something?
 Metal auto sump & fluid change (3 hrs)
LR door puddle projectors (10 mins)
Tinted Bonnet wind deflector (10 mins)
All Intercooler pipes and Tbolts (2hrs)
3 injectors replaced so far (30mins)
Sunroof drain pipes both sides 2.5 hrs)
Rear discs, shoes,pads,callipers,flexi hoses, rigid brake line, n/s upper hub carrier bush and rear n/s upper arm (13hrs over 2 days) 
 
Post #18764236th Nov 2017 7:44 pm
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Martin
Site Admin and Owner 


Member Since: 06 Nov 2004
Location: Hook Norton
Posts: 18440

United Kingdom 2006 Discovery 3 TDV6 SE Manual Buckingham BlueDiscovery 3

Yes It pulses voltage to run the pump, the pump should tick when the FBH operates, not whirr Smile
 06 D3 SE / 15 LR D90 XS SW / 88 LR 90 Td5 / 68 BMW 2000 ti
Any issues with the site let me know! 
 
Post #18764246th Nov 2017 7:45 pm
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lynalldiscovery
 


Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274

United Kingdom 2006 Discovery 3 TDV6 Metropolis LE Auto Bonatti GreyDiscovery 3

You can apply and remove 12v supply multiple times to simulate the pumps power supply, its crude but is good enough for testing.
  
Post #18764366th Nov 2017 8:01 pm
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Martin
Site Admin and Owner 


Member Since: 06 Nov 2004
Location: Hook Norton
Posts: 18440

United Kingdom 2006 Discovery 3 TDV6 SE Manual Buckingham BlueDiscovery 3

Whistle
 06 D3 SE / 15 LR D90 XS SW / 88 LR 90 Td5 / 68 BMW 2000 ti
Any issues with the site let me know! 
 
Post #18764376th Nov 2017 8:02 pm
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Dazz360
 


Member Since: 03 Sep 2016
Location: West Mids Walsall
Posts: 871

United Kingdom 2005 Discovery 3 TDV6 HSE Auto Bonatti GreyDiscovery 3

I’ve checked the earth Black to the pump good continuity also tried applying 12v on off on off whilst sucking fuel pipe at fbh end and nothing am I meant to prime the pump some way ??
 Metal auto sump & fluid change (3 hrs)
LR door puddle projectors (10 mins)
Tinted Bonnet wind deflector (10 mins)
All Intercooler pipes and Tbolts (2hrs)
3 injectors replaced so far (30mins)
Sunroof drain pipes both sides 2.5 hrs)
Rear discs, shoes,pads,callipers,flexi hoses, rigid brake line, n/s upper hub carrier bush and rear n/s upper arm (13hrs over 2 days) 
 
Post #18764406th Nov 2017 8:09 pm
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Disco dazboy
 


Member Since: 02 Dec 2013
Location: Leicestershire
Posts: 1782

United Kingdom 2008 Discovery 3 TDV6 XS Auto Stornoway GreyDiscovery 3

I had this trouble on my old disco I had to use a random pump of a car borrowed off a mate to use first to get the fuel up the pipe then swap back to disco pump! Once the fuel was up the pipe it worked fine but just didn't have enough suction to start the job off! Thumbs Up
 D3 x2 now gone
Volkswagen Tiguan Allspace 4motion 
 
Post #18764486th Nov 2017 8:33 pm
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Dazz360
 


Member Since: 03 Sep 2016
Location: West Mids Walsall
Posts: 871

United Kingdom 2005 Discovery 3 TDV6 HSE Auto Bonatti GreyDiscovery 3

Thanks Daz, I’ve got the fuel up to the fbh by crudely tapping 12v to the pump, when the heater runs on start up the pump at no point tries to click
 Metal auto sump & fluid change (3 hrs)
LR door puddle projectors (10 mins)
Tinted Bonnet wind deflector (10 mins)
All Intercooler pipes and Tbolts (2hrs)
3 injectors replaced so far (30mins)
Sunroof drain pipes both sides 2.5 hrs)
Rear discs, shoes,pads,callipers,flexi hoses, rigid brake line, n/s upper hub carrier bush and rear n/s upper arm (13hrs over 2 days) 
 
Post #18765096th Nov 2017 9:59 pm
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Dazz360
 


Member Since: 03 Sep 2016
Location: West Mids Walsall
Posts: 871

United Kingdom 2005 Discovery 3 TDV6 HSE Auto Bonatti GreyDiscovery 3

I think it’s locked out
 Metal auto sump & fluid change (3 hrs)
LR door puddle projectors (10 mins)
Tinted Bonnet wind deflector (10 mins)
All Intercooler pipes and Tbolts (2hrs)
3 injectors replaced so far (30mins)
Sunroof drain pipes both sides 2.5 hrs)
Rear discs, shoes,pads,callipers,flexi hoses, rigid brake line, n/s upper hub carrier bush and rear n/s upper arm (13hrs over 2 days) 
 
Post #18765116th Nov 2017 10:00 pm
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Disco dazboy
 


Member Since: 02 Dec 2013
Location: Leicestershire
Posts: 1782

United Kingdom 2008 Discovery 3 TDV6 XS Auto Stornoway GreyDiscovery 3

Sounds like the fbh is at fault! You could do with trying another fbh to see if it cures it! Anyone local you could borrow one off?
 D3 x2 now gone
Volkswagen Tiguan Allspace 4motion 
 
Post #18765156th Nov 2017 10:07 pm
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