↓ Advertise on Defender2 ↓

Home > Puma (Tdci) > Fuel Gauge Not Working, Now Won't Start
Post Reply  Down to end
Page 1 of 1
Print this entire topic · 
dannyragsdale



Member Since: 06 Oct 2022
Location: Eastern Highlands, PNG
Posts: 40
Papau New Guinea 2012 Defender 110 Puma 2.2 HT Fuji White
Fuel Gauge Not Working, Now Won't Start
I just got a 2012 Defender 110 Puma and it has a fuel gauge problem. Has anyone else had a problem with their fuel gauge all of a sudden not working? Down to nothing and now the low fuel light flashes at me. I guess there is a computer control where after a certain amount of time running like this, it automatically kills it. Called a "Run Dry Prevention Control".

Does changing out the fuel sending unit fix this? Is there a bypass for this? Anyone else run into this before?

And yes, the tank is completely full so I'm not rushing to drop the tank in order to start playing with the sending unit.

Thanks for any advice and help!
Post #971060 14th Nov 2022 7:03am
View user's profile Send private message View poster's gallery Reply with quote
blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17610
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
If the vehicle thinks it is low on fuel it will activate the "low fuel" strategy, which involves a simulated misfire and eventually shuts down the engine with inhibited restart (certainly this is the case for the 2.4 and is intended to prevent the ingress of air into the fuel lines since they're not easy to bleed, the 2.2 with a tank mounted pump may be different).

The only way the vehicle knows how much fuel is on board is via the sender in the tank, so an electrical fault which has the effect of indicating an empty tank will cause not only the gauge to show empty, the light to come on, but will also prevent the engine from starting (actually quite handy as an extra layer of security).

My first thought is that you have a loose or disconnected wire (or possibly a short to ground) between the tank and the ECM. I would have to look at the schematics to figure out whether it is an open circuit or short circuit though. It is also possible that it is a faulty sender (or I suppose a faulty ECM), of course.
Post #971079 14th Nov 2022 10:00am
View user's profile Send private message View poster's gallery Reply with quote
ickle



Member Since: 22 Jul 2010
Location: South Vendee
Posts: 1822
France 2008 Defender 110 Puma 2.4 CSW Alpine White
As an aside, its very easy to make a small inspection hatch over the sender unit through the rear floor, makes life easy for inspection and repair....

hth Keith
Post #971134 14th Nov 2022 5:45pm
View user's profile Send private message View poster's gallery Reply with quote
dannyragsdale



Member Since: 06 Oct 2022
Location: Eastern Highlands, PNG
Posts: 40
Papau New Guinea 2012 Defender 110 Puma 2.2 HT Fuji White
Thanks Blackwolf for the more technical data. That's helpful!


Ickle: Did you do that with the tank in and do it from the top? Or did you drop the tank and then do the work so you won't have to drop the tank again? Thanks for the idea!
Post #971157 14th Nov 2022 8:30pm
View user's profile Send private message View poster's gallery Reply with quote
blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17610
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
It's actually not difficult to drop the tank on a 110, the 90 is much more tricky.
Post #971165 14th Nov 2022 9:15pm
View user's profile Send private message View poster's gallery Reply with quote
dannyragsdale



Member Since: 06 Oct 2022
Location: Eastern Highlands, PNG
Posts: 40
Papau New Guinea 2012 Defender 110 Puma 2.2 HT Fuji White
Ok. I'm planning on dropping the tank on Friday or Saturday and will come back with an answer if I find one.
Post #971185 15th Nov 2022 3:25am
View user's profile Send private message View poster's gallery Reply with quote
ickle



Member Since: 22 Jul 2010
Location: South Vendee
Posts: 1822
France 2008 Defender 110 Puma 2.4 CSW Alpine White
Its easy to make the hatch with the tank in place, there's a few threads on it I did it to fit a new dip tube and pump for a night heater.
Post #971188 15th Nov 2022 6:32am
View user's profile Send private message View poster's gallery Reply with quote
Martin
Site Admin


Member Since: 02 Apr 2007
Location: Hook Norton
Posts: 6642
United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
If you have a multimeter it would be worth popping the instrument cluster out, removing the plug and checking the resistance across the fuel tank sensor wires.  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #971189 15th Nov 2022 6:43am
View user's profile Send private message View poster's gallery Send e-mail Reply with quote
dannyragsdale



Member Since: 06 Oct 2022
Location: Eastern Highlands, PNG
Posts: 40
Papau New Guinea 2012 Defender 110 Puma 2.2 HT Fuji White
Martin: How much resistance would I find there? What is in spec? Thanks for the tip!
Post #971201 15th Nov 2022 9:55am
View user's profile Send private message View poster's gallery Reply with quote
Martin
Site Admin


Member Since: 02 Apr 2007
Location: Hook Norton
Posts: 6642
United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
2.2 spec is 50 Ohms full, 1000 Ohms empty.

You could also check at the grey chassis loom connectors under the right hand seat.

At the cluster you want to measure resistance between pins 8 and 31.

For the chassis loom, disconnect the grey connector pair, and on the connector with male pins (this goes to the tank) test between pins 6 and 7.

Wire colours are green with orange, and yellow with purple.

Martin  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #971203 15th Nov 2022 10:17am
View user's profile Send private message View poster's gallery Send e-mail Reply with quote
blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17610
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
^^ Useful info., do you know if it is the same for a 2.4?

The fact that the higher impedance indicates an empty tank suggests that an open circuit would be interpreted as zero fuel, unless "the system" is clever enough to know that an infinite impedance indicates a fault.
Post #971238 15th Nov 2022 4:45pm
View user's profile Send private message View poster's gallery Reply with quote
Martin
Site Admin


Member Since: 02 Apr 2007
Location: Hook Norton
Posts: 6642
United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
Everything 2.4 and earlier is 19 Ohms full, 270 Ohms empty.  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #971249 15th Nov 2022 7:40pm
View user's profile Send private message View poster's gallery Send e-mail Reply with quote
blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17610
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
Thank you Thumbs Up
Post #971252 15th Nov 2022 7:58pm
View user's profile Send private message View poster's gallery Reply with quote
dannyragsdale



Member Since: 06 Oct 2022
Location: Eastern Highlands, PNG
Posts: 40
Papau New Guinea 2012 Defender 110 Puma 2.2 HT Fuji White
So I finally had time to look at things. I ended up pulling the whole fuel tank out and I honestly don't regret it. Wasn't too bad after I siphoned out the fuel.

Pulled the fuel pump out and nothing looked out of place. Pulled the multimeter out and started going at things. I started with ohming the plug on top of the fuel pump assembly and trying to test the sending unit float. I set it up and found it was completely open. Nothing at all. Was happy to find that because it meant that my sending unit was bad, right? Wrong! My friend that was helping me decided to check from the bottom side where the sending unit plug connects into the top of the fuel pump and sure enough it was perfectly like Martin said, 50 ohms full and 1000 empty. What a relief to see that and know what was wrong for sure!

All that to say is that I am ordering both the fuel pump assembly and the sending unit. I'm out of commission for one of them so might as well order both and not have to worry about it for a long time.

Do you guys have any suggestions on who to order from? I've been building a wish list of other things it needs on LR Workshop. It looks like I could order everything I need/want from Island 4x4 or LR Direct, but LR Direct would be about $100 USD more than Island. Anything wrong with Island 4x4 and their stuff?

Thanks for all the help!
Post #971540 18th Nov 2022 9:15am
View user's profile Send private message View poster's gallery Reply with quote
dannyragsdale



Member Since: 06 Oct 2022
Location: Eastern Highlands, PNG
Posts: 40
Papau New Guinea 2012 Defender 110 Puma 2.2 HT Fuji White
The fact that I live in PNG means that parts take a long time and I was getting impatient waiting the parts get here (ordered Sunday and they still haven't processed the order or shipped it as of Wednesday night).

So I went after the pump and drenched the electrical connectors with terminal/contact cleaner and let it set for a while. Cleaned it all off. Took a small file and cleaned the connectors as much as possible. Then tested the resistance and sure enough, I was able to get a reading through the connector this time! Hooked it up to the harness and propped the float up and the gauge up front read correctly! So excited that I am able to get going again for the time being.

Thanks again for all the help.
Post #972108 23rd Nov 2022 9:40am
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 1 of 1
All times are GMT

Jump to  
<  Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2006-2025 Futuranet Ltd & Martin Lewis
DEFENDER2.NET RSS Feed - All Forums