Member Since: 30 Nov 2014
Location: Southend on Sea
Posts: 180
FBH Bench test rig - initial error help!
I bought a secondhand FBH, which was running per the forum member that sold it, it did have some sporadic misfires but did run.
I wanted to test this and keep as a working spare so I built a test wiring rig per the attached
The heater has been cleaned and reassembled per Robbies guide, I have a spare Fuel pump from a Thermo Top C/V as I use these on my Narrow Boat for Central Heating!
The USB to OSBII lead is working as this has been used before, I have doubled checked all the cabling joints and the whole thing is connected to a fully charged car battery. However the webasto software just tells me that it cannot connect to the Diagnostics adapter.
Click image to enlarge
On the 8 pin plug the blue wire is diagnostics and Red is Fuel pump.
Click image to enlarge
Click image to enlarge
Was wanting to connect to it so I could prime the fuel and then do a test fire up etc.
Anyone any clues as to why I am getting the "Unable to connect" messages?
2nd Jan 2017 3:24 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Bridge together OBD pins 4 & 5.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 23 Oct 2016
Location: Northants
Posts: 93
Hi,
I cant find a full wiring diagram of the FBH plug, but my guess (from your diagram) is that you are missing the equivalent of the chassis ground and so effectively there is no chassis (or -Ve) connection and so effectively its not got any power to it and so hence no comms.
The OBD connection certainly has a chassis ground within it (Which of course would be connected to the same chassis ground of the FBH etc.
These things can cause problems and so in your (great!) test rig I would emulate the chassis of the vehicle by connecting them all together with some pretty thick cable and then connect the -ve (black) connection to that.
Might help or might not but worth a try perhaps !
Others will have better ideas maybe
2nd Jan 2017 3:56 pm
Nc1989
Member Since: 28 Apr 2015
Location: Doncaster
Posts: 214
Fuel pump from the Thermo top C won't work, you need the correct V / D3 pump
2nd Jan 2017 4:34 pm
Dai-Disco3
Member Since: 30 Nov 2014
Location: Southend on Sea
Posts: 180
Hi Guys thanks for the feedback so far, connected 4 and 5 per Robbie and now have connectivity and was able to get fuel pump to deploy fuel, well it was pumping out of the fuel pipe when not connected to the FBH.
Tried a test fire and seems there is nothing happening with glow plug as Diag software shows nothing on the line, there was a value on the Flame detector, supply voltage over 12.5 volts and combustion fan whirred into life.
So may have a glow plug fault, will look at this tomorrow, however any more ideas please let me know, as I know this being on the "bench" is a little unusual.
2nd Jan 2017 5:33 pm
Madrilleno
Member Since: 13 Oct 2014
Location: Nottingham
Posts: 1788
Following this thread with interest as I need t bench test my spare when it's cleaned out. More pics of setup would be useful please.There are two rules for success,
1. Never tell everything you know.
D4 gone!
D5
2nd Jan 2017 5:36 pm
Dai-Disco3
Member Since: 30 Nov 2014
Location: Southend on Sea
Posts: 180
Basically the set up is:
A plastic tub with two holes drilled in it with tank connectors to allow the 3/4 inch rubber pipes to be connected.
The pipes then connected to the spigots on the heater, Have turned the one not connected to the pump through 90 degrees to aid connections
Wiring as per diagram, (now after Robbies input)
Diesel in a can
Pump (possibly one that wont work) from can to fuel in spigot.
Note if you try doing this you must be in well ventilated garage as you can kill yourself with the CO2!!
2nd Jan 2017 5:44 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Dai-Disco3 wrote:
Hi Guys thanks for the feedback so far, connected 4 and 5 per Robbie and now have connectivity and was able to get fuel pump to deploy fuel... nothing happening with glow plug as Diag software shows nothing on the line, there was a value on the Flame detector...
Glad it helped.
The glow plug and flame detector are one and the same. If all the conditions are not met then the glow plug does not go into high-heat mode. Parameters include the fuel system so if this is not fully compatible then this could be the cause.
The Webasto software should show the glow plug control trigger even if the glow plug has failed. If there is no trigger then the plug has not been commanded on by the control unit.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 13 Oct 2014
Location: Nottingham
Posts: 1788
Thanks gents. Anyone have a spare pump I could borrow/buy at some point?There are two rules for success,
1. Never tell everything you know.
D4 gone!
D5
2nd Jan 2017 7:14 pm
Nc1989
Member Since: 28 Apr 2015
Location: Doncaster
Posts: 214
To expand on my previous point, you need the correct fuel pump for the heater. Pretty much any webasto pump will work electronically but different pumps deliver different amounts of fuel per pulse. The D3 pump runs at twice the frequency but delivers half the amount per pulse. it's a noise and vibration thing.
from what I can just about see from the pics, you have the wrong pump so it will overfuel. That rubber fuel hose also won't help, you need the smaller bore webasto stuff or else it won't deliver the right amount of fuel.
2nd Jan 2017 7:29 pm
Dai-Disco3
Member Since: 30 Nov 2014
Location: Southend on Sea
Posts: 180
Will be trying some more things today with this, but does anyone have a spare pump i can borrow to get this test rig working.
Happy for this then to be a loan test wiring rig for use by forum members so we can bench test heaters
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and now have connectivity and was able to get fuel pump to deploy fuel, well it was pumping out of the fuel pipe when not connected to the FBH.
