Huttojb
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| posted on 30/9/16 at 09:19 PM |
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Fuel Sender
Hey all,
I'm measuring my fuel sender on my Tiger Avon, I measured the resistance @ 239.30 Ohms. I then emptied the tank, removed 2 litres of fuel. The
resistance fell to 239.20 Ohms.
Does this seem correct?
I thought 2 litres would change the resistance more??
Jason.
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gremlin1234
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| posted on 30/9/16 at 09:40 PM |
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maybe the float has reached the end of its travel. so shows empty for 2l and under. what does it read full?
ps to fix it you may need to adjust (ie bend...) the arm
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Huttojb
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| posted on 2/10/16 at 10:22 AM |
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All
Following my earlier post I have decided that my fuel sender makes no logically sense.
I have emptied my tank and measured the resistance at 281ohms. I put in 5 litres if fuel and measured 320 Ohms. At this point I was feeling very
pleased with myself and expecting an increase in Ohms relative to fuel. I then put another 5 litres (giving me 10 litres of fuel) and my
'stupid' fuel sensor decided to wreck my Sunday afternoon with a reading of 172 Ohms.
So to recap;
0 litres 281 Ohms
5 litres 320 Ohms
10 litres 172 Ohms.
This has also changed to when I measured an empty tank yesterday.
If I could swear on here I would!!! How am I suppose to logically work out how much fuel I have!!!
Advise, words or wisdom or sympathy welcome.
Jason.
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Smoking Frog
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| posted on 2/10/16 at 10:55 AM |
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If you have isolated the sender from the loom and the float is raising and falling as it should. Then yes, that is confusing. Remove
sender from tank. Check readings once more by moving the float up and down manually. If it's still the same replace.
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Huttojb
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| posted on 2/10/16 at 11:12 AM |
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Thanks Mr Frog.
Yeah the sender is isolated, to remove the sensor I have to drop the tank out so was trying to avoid that.
I might take the fuel back out and try again. Maybe when I took the 5 litre reading the measurement wasn't settled. I have also gone the other
way and measured the gauge and it seems the gauge is configured to 280ohm Empty and 40 Ohms full. This would match my 0 litres and 10 litres reading,
Is there a delay in the sender to settle? How reactive is the sender normally.
Jason.
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gremlin1234
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| posted on 2/10/16 at 11:19 AM |
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since most of these senders are a wipe contact to the resistance, it may just need a bit of cleaning.
the easiest way to do this is just move the float up and down a few times.
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Smoking Frog
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| posted on 2/10/16 at 11:34 AM |
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quote:
Is there a delay in the sender to settle? How reactive is the sender normally.
No delay when taking readings using a multi meter from the sender. Resistance is smoothed out at the fuel gauge.
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Huttojb
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| posted on 3/10/16 at 10:47 AM |
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Ok,
I have removed my fuel tank, and the fuel sender doesn't seem to have any way of removing. There's loads of silicon around it but surely
there's a way to remove it.
Jason.
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Huttojb
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| posted on 3/10/16 at 10:56 AM |
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Don't know how to put a photo in?
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gremlin1234
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| posted on 3/10/16 at 11:05 AM |
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quote:
Originally posted by Huttojb
Don't know how to put a photo in?
see http://www.locostbuilders.co.uk/viewthread.php?tid=202618
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Huttojb
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| posted on 3/10/16 at 11:59 AM |
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All
Please see below, My fuel sender - do i just remove the silicon and pull it out?
 
GenFuelSender
(If it works)
I have also attached a picture of my car - because I can!!
 
huttojb_GenTiger
 
huttojb_GenDash
 
huttojb_GenCockPit
Jason
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907
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| posted on 3/10/16 at 12:21 PM |
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Three things it might help you to know:-
Silicon and petrol doesn't mix. It goes to jelly.
All electrical contacts should be clean. This is especially important when a gauge is trying to measure small differences.
To allow for voltage fluctuations some gauges require a lower feed voltage. I have a Smiths gauge in conjunction with
a Ford sender and the gauge is fed by 9.9v/10v.
HTH
Paul G
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Huttojb
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| posted on 3/10/16 at 12:28 PM |
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quote:
Originally posted by 907
Silicon and petrol doesn't mix. It goes to jelly.
Thanks 907
My sender seems to be a resistance down to ground. I'm not directly connecting the sender to the gauge and controlling these seperatly (will
explain in a different post).
I have now removed the sender, and it seems the issue is connection on the external face, i might need to clean it up - whats the best
"household methord to clean the external face and connections.
What should i use to seal the sender once refitted?
Jason
[Edited on 3/10/16 by Huttojb]
Jason
huttojb_GenTiger
There are only 10 types of people in the world. Those that understand binary and those that don’t.
If only DEAD people understand hexadecimal - 57,005
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Huttojb
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| posted on 3/10/16 at 03:32 PM |
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Thanks all for your help, just an update.
I have now cleaned the connections and exercised the wiper. This has resolved my intermittent and unexpected reading.
Just a few questions,
The sender was fitter into the tank and had some sort of silicon around it. What silicon / glue / fuel resistive sealant I can use. The sender is not
a great fit and it is required.
Jason
huttojb_GenTiger
There are only 10 types of people in the world. Those that understand binary and those that don’t.
If only DEAD people understand hexadecimal - 57,005
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gremlin1234
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| posted on 3/10/16 at 04:29 PM |
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a very quick search for "petrol safe sealant"
suggests
hylomar blue
edit: remember thats only a sealant, not a glue
[Edited on 3/10/16 by gremlin1234]
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rusty nuts
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| posted on 3/10/16 at 06:15 PM |
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Your sender looks like it is probably from a production car of some sort? possibly a Sierra? It should have a fuel proof "O" ring as a
seal sitting in a groove on the underside of the mounting flange .
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Huttojb
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| posted on 3/10/16 at 06:34 PM |
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quote:
Originally posted by rusty nuts
Your sender looks like it is probably from a production car of some sort? possibly a Sierra? It should have a fuel proof "O" ring as a
seal sitting in a groove on the underside of the mounting flange .
Hey Rusty Nuts, it does - but like I said - whoever cut the hole fror the sender to sit into the tank, it isn't a great fit and wouldn't
be water tight when inserted.
Also - I am measuring the resistance fromt the fuel sender by using a 5V signal and measuring the voltage across the potential divider.... as I have
been advised, petrol goes **BOOM**!!! Would this be ok?
Jason
[Edited on 3/10/16 by Huttojb]
Jason
huttojb_GenTiger
There are only 10 types of people in the world. Those that understand binary and those that don’t.
If only DEAD people understand hexadecimal - 57,005
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gremlin1234
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| posted on 3/10/16 at 07:00 PM |
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quote:
Also - I am measuring the resistance fromt the fuel sender by using a 5V signal and measuring the voltage across the potential divider.... as I
have been advised, petrol goes **BOOM**!!! Would this be ok?
its quite normal to have a 12V potential divider/resistance in the tank. only
gets dangerous when its very cold. look up vapour pressure, and/or buncefield
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Huttojb
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| posted on 3/10/16 at 07:13 PM |
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Thank you; I ahve just looked at;
https://en.wikipedia.org/wiki/Vapor_lock
Is this why there is a gas bleed valve (not sure what to call it) on top of the fuel tank to remove any harmful gas...
So in your opionion providing a 5V to the fuel sender should be ok - I beleive this is what the gauges do, because I don't know how else you
would measure the resistance?
Jason
huttojb_GenTiger
There are only 10 types of people in the world. Those that understand binary and those that don’t.
If only DEAD people understand hexadecimal - 57,005
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gremlin1234
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| posted on 3/10/16 at 07:22 PM |
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quote:
Originally posted by Huttojb
Thank you; I ahve just looked at;
https://en.wikipedia.org/wiki/Vapor_lock
Is this why there is a gas bleed valve (not sure what to call it) on top of the fuel tank to remove any harmful gas...
So in your opionion providing a 5V to the fuel sender should be ok - I beleive this is what the gauges do, because I don't know how else you
would measure the resistance?
yes 5V / 12V across the 'sender' is quite safe. another counter-intuitive point is that a nearly
empty tank in much more likely to explode than a full one...!
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Huttojb
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| posted on 3/10/16 at 07:33 PM |
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quote:
Originally posted by gremlin1234
explode
YOUR NOT HELPING - lol!!!!!
Jason
huttojb_GenTiger
There are only 10 types of people in the world. Those that understand binary and those that don’t.
If only DEAD people understand hexadecimal - 57,005
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gremlin1234
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| posted on 3/10/16 at 07:47 PM |
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quote:
Originally posted by Huttojb
quote:
Originally posted by gremlin1234
explode
YOUR NOT HELPING - lol!!!!!
actually vastly more dangerous to do fuel transfers in 'free air' - ie fill you car at a petrol
station, or worse from a plastic can.
reason being it takes a huge amount of air to let the fuel burn that quick.
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