FBH The end of the SAGA ?

[FrenchMike]

Originally Posted by HarryM1BYT

The easy way to know whether the pump is working, is to listen to it for clicks. The speed of the clicks vary, depending on the combustion state of the FBH, but they are easily heard. If its clicking you can be 99% sure it is pumping, but that doesn't guarantee fuel is coming out.

Yes Harry and if fuel refuses to come ,a flame out error is generated and
the burner stops ...



Mike

[wolfdoguk]

Originally Posted by sln8458

Paul
Just a thought, the fuel pump is solenoid driven (it has a pulse signal) so the light should 'flash' in sync with the pump.
As mentioned in Mikes post #121
I think you could have a fuel pump issue, hence why both FBH's have issues when fitted to the car.

SteveN

Hi Steve,
Thanks for that, I was actually doing the light bulb test with the unit inactive, I wasn't 100% sure whether I was supposed to do it that way or not. However, after fiddling about with the pcb, I got it working again, and it's working now, although I've cut the wire from the temp sensor, so I only use it as a parking heater. I was concerned too about a pump issue, but I wondered if the wiring was shorting somewhere, as the previously mentioned pcb was very black, making me think it was completely shot because of a short or something, especially when the unit before stopped working too, and seeing that the only things wired externally of the fbh's, are the temp sender and the pump, or maybe it was a coincidence both units died?

Originally Posted by HarryM1BYT

The easy way to know whether the pump is working, is to listen to it for clicks. The speed of the clicks vary, depending on the combustion state of the FBH, but they are easily heard. If its clicking you can be 99% sure it is pumping, but that doesn't guarantee fuel is coming out.

Yes Harry, the pump is working, its clicking as the fbh wants it to, slowly at the start and getting faster as the fbh gets up to full speed and maintaining it until its switched off. When the car ate the burners, I tested the pump directly via the terminals, and it clicked as it should.


Thanks very much to everyone, especially Mike!

[HarryM1BYT]

Originally Posted by wolfdoguk

Hi Steve,
Thanks for that, I was actually doing the light bulb test with the unit inactive, I wasn't 100% sure whether I was supposed to do it that way or not. However, after fiddling about with the pcb, I got it working again, and it's working now, although I've cut the wire from the temp sensor, so I only use it as a parking heater.

Fiddling about with it and it starting to work, might suggest it went into lockout....

If it tries to start three times in succession and fails to get ignition, it goes to lockout. It then remains locked out, until reset. You reset it by pulling the fuse or power plug, out briefly.

[wolfdoguk]

Originally Posted by HarryM1BYT

Fiddling about with it and it starting to work, might suggest it went into lockout....

If it tries to start three times in succession and fails to get ignition, it goes to lockout. It then remains locked out, until reset. You reset it by pulling the fuse or power plug, out briefly.

Yes, that was the problem to start with Harry, I thought it was in lockout and reset it so many times that I lost count. The other unit would start running as soon as power was applied, well, the fan started running at high speed for about a minute then stop, putting, grounding pin 3 would start the fan at high speed again along with the water punp, and stop after a couple of minutes. As you say, three times and it went into lockout, so I would reset, and the whole process would start again. K bus is disconnected. I traced back to problematic 4k7 resistor on that particular pcb.

[Spike05reg]

Hi Guys,
Hope you don't mid my asking, my 2005 year MG fbh hasn't worked since 2012. I dekoked it last week. The air fan was stuck and full of debris, and now it works if i give it 12v on pin 1, and successfully heats up the engine. Left to its own devices, nothing happens. The car's harness gives no signal on pin 1 regardless of the outside temp. Where should I look next please?
Mike.

[Snagger]

Originally Posted by Spike05reg

Hi Guys,
Hope you don't mid my asking, my 2005 year MG fbh hasn't worked since 2012. I dekoked it last week. The air fan was stuck and full of debris, and now it works if i give it 12v on pin 1, and successfully heats up the engine. Left to its own devices, nothing happens. The car's harness gives no signal on pin 1 regardless of the outside temp. Where should I look next please?
Mike.

If the unit is not starting at the correct temperature suspect faulty temp sensor, or wiring.

See 2nd and 3rd links in my signature.

Be aware if you need to change the temp sensor and you use the land rover ( L ) coded one from Rimmers, it will trigger the FBH at approx +10 deg or less, as opposed to the Rover oem one at +5deg or less.

Snagger.

[HarryM1BYT]

Originally Posted by Spike05reg

Hi Guys,
Hope you don't mid my asking, my 2005 year MG fbh hasn't worked since 2012. I dekoked it last week. The air fan was stuck and full of debris, and now it works if i give it 12v on pin 1, and successfully heats up the engine. Left to its own devices, nothing happens. The car's harness gives no signal on pin 1 regardless of the outside temp. Where should I look next please?
Mike.

Run signal is produced by the alternator being driven, it then goes to a thermostat behind the front bumper, set to close at or around +5C. So engine running and outdoor temperature needs to be below +5C before the FBH will run automatically.

Check my FBH Help by clicking the link below....

[bigbaldbloke]

Spike, if you don't mind me asking - did you "just" remove the top cover to sort the fan out?

Kev

[Spike05reg]

Many thanks Snagger and Harry. I'll go looking this weekend.
Kev, no, I stripped the whole shebang to dekoke it because I didn't know what I would find after a few years of inactivity. I couldn't see how the fan impellor came off, so I blew through the fan with compressed air, then ran it on 12v for a while shaking it to clear any dirt inside.
Thanks again,
Mike.

[Martin_J]

Thank you Mike for all your job you do here!

I am a newbie on this forum – found it recently. Thanks to this great discussion I could have discovered the same resistor problems on my Webasto PCB as well.

My Webasto had four problem resistors on the microprocessor side and one problem resistor on the flip side!

The Webasto however does not work yet. By mistake I have damaged part near processor and now I do not know what part is was.

Could someone possibly let me know the code marking which has been written on the part? I would try to replace it first and then carry on testing.



Thanks a lot Martin