Lotus Elan

Amperage for fuel tank sending unit

PostPost by: fattogatto » Wed Sep 29, 2021 4:46 pm

I am assuming the original Elan wiring simply ganged the fuel level sender power with everything else and ran it through one of the two fuses. I have a spare fuse or two - any issues with running it through a dedicated 3 amp fuse? I wouldn't think so, but with a Lotus you never know.

Thanks.
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PostPost by: Slowtus » Wed Sep 29, 2021 5:20 pm

fattogatto wrote:I am assuming the original Elan wiring simply ganged the fuel level sender power with everything else and ran it through one of the two fuses. I have a spare fuse or two - any issues with running it through a dedicated 3 amp fuse? I wouldn't think so, but with a Lotus you never know.

Thanks.



Just curious as to why isolate/fuse THAT particular gauge ?
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PostPost by: oldelanman » Wed Sep 29, 2021 6:29 pm

Don't forget the fuel gauge needs a10 volt supply and is fed via a voltage stabiliser, not directly from the main fuse. You will need to take that into account if you re-arrange the wiring.
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PostPost by: steve lyle » Thu Sep 30, 2021 8:01 am

If you do feel compelled to do this, I wold expect the amp draw to be in the milli-amp range for any sensor, or relay for that matter, so a 1 amp fuse would be more than adequate.
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PostPost by: ericbushby » Thu Sep 30, 2021 10:00 am

Hi Charles.
I have the later bimetal strip type gauge fitted in my car.
Tests showed :-
Tank empty sender at 230 Ohms 37 mA
Tank full sender at 24 Ohms 210 mA
Supply voltage 10V
I have no experience on the earlier type of gauge which uses a 90 Ohm sender
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PostPost by: Slowtus » Thu Sep 30, 2021 4:54 pm

I'm still curious as to why...
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PostPost by: fattogatto » Thu Sep 30, 2021 7:10 pm

I thought I had explained I have two spare fuse slots to use. Do you feel there is a real problem with sticking a 1 amp fuse in the circuit?
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PostPost by: fattogatto » Thu Sep 30, 2021 7:11 pm

oldelanman wrote:Don't forget the fuel gauge needs a10 volt supply and is fed via a voltage stabiliser, not directly from the main fuse. You will need to take that into account if you re-arrange the wiring.


Thanks. I am using the standard wiring harness that goes through the voltage stabilizer in the tach.
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PostPost by: Slowtus » Thu Sep 30, 2021 10:57 pm

fattogatto wrote:I thought I had explained I have two spare fuse slots to use. Do you feel there is a real problem with sticking a 1 amp fuse in the circuit?


I read and understood that you have two spare slots.

I am just curious as to why you wish to use either of them for the fuel gauge - just curious.
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PostPost by: fattogatto » Thu Sep 30, 2021 11:37 pm

Use them or lose them. If available why not?
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PostPost by: Slowtus » Thu Sep 30, 2021 11:50 pm

fattogatto wrote:Use them or lose them. If available why not?



The least important gauge for me, beyond "ambient temperature" would be the fuel gauge.

In almost 60 years of driving I have never had a failure of the fuel gauge/sender, in Lotus and other cars except for a 2006 Ford Ranger where, when it ran dry, it actually went towards the 'full' indicator on the gauge, stranding me on a quiet country road. :)

Me, if I REALLY wanted to 'fuse' a gauge, it would be the oil pressure one 'specially on a Lotus (on the non mechanical ones) or the temp gauge, ditto.

That said, it is your car so go ahead, fill your boots (and, ideally, your gas tank). :D
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PostPost by: billwill » Fri Oct 01, 2021 12:31 am

fattogatto wrote:
oldelanman wrote:Don't forget the fuel gauge needs a10 volt supply and is fed via a voltage stabiliser, not directly from the main fuse. You will need to take that into account if you re-arrange the wiring.


Thanks. I am using the standard wiring harness that goes through the voltage stabilizer in the tach.


The Voltage Stabalizer is NOT in the tach!! It is merely earthed to the case of the tachometer and does not share any real circuits with it at all.

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PostPost by: Billmack » Fri Oct 01, 2021 7:26 pm

No problem at all. You might want to hit it from before the stabilizer though. O ce in a blue moon those short out. They dont work unless grounded
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