Board logo

Fuel tank and sender woes
Avoneer - 17/2/04 at 09:56 PM

When the tank sender is disconnected, should the gauge go to "beyond" full and only drop to the correct level when the sender is connected?
Pat....

Hellfire - 18/2/04 at 12:40 AM

Think about that logically...

Does the gauge go beyond full when in the off position?

I believe the gauge drops below zero when no power (so disconnected) sounds like you have a short inside the sender, or you have the wires connected to the sender the wrong way around so connecting feed straight to earth (but this should blow fuse!) is giving you a full 12V signal.

elitewiring - 18/2/04 at 01:39 AM

avoneer,
is your sender matched to your indicator.
the reason i ask is because there are generally two types of senders/indicator systems in use.
the 1st: 260 ohms res (sender) at empty, 20 ohms res at full. the 2nd: 10 ohms res at empty, 180 ohms res at full. therefore if you had a system set up as the 2nd ie high resistance when full when you disconnect the indicato to sender signal wire you would be simulating a full tank.
i would advise you to check what sender and indicator you have before doing anything else.
note mid 80's fords used the 1st set up.

GO - 18/2/04 at 12:31 PM

Here's a question for ya...

Every older car that I can remember the fuel guage drops down below zero when the ignition is switched off. But, on new cars, the gauge continues to read the actual level with ign off.

How do they do that then?

jonti - 18/2/04 at 12:46 PM

quote:
Originally posted by GO
Here's a question for ya...

Every older car that I can remember the fuel guage drops down below zero when the ignition is switched off. But, on new cars, the gauge continues to read the actual level with ign off.

How do they do that then?


I presume it's done the same way the sidelights, courtsey lights, hazards etc still work...it takes its power from an unswitched source...or praps there's a long steel rod connected to the float in the tank which pushes the needle up in the gauge..( I like that idea, nice and mechanical )

Re original question..sounds like you have got a mismatch or using wrong or wrong way round terminals on your gauge

GO - 18/2/04 at 12:54 PM

quote:

it takes its power from an unswitched source


doh, that would be the easy way to do wouldnt it!!

you can tell I'm no genius with electrics! think I prefer the mechanical approach as well!

Deckman001 - 18/2/04 at 01:10 PM

Replaced one the other day in an Indy, it had a sender from luego and a std sierra pod , when the terminals on the sender were placed on the wrong way round, it gave a full reading when actually empty, swapped the around , and hey presto perfik !!
Might help if you say what sender you have and also what instruments it is feeding

Jason

Avoneer - 18/2/04 at 04:01 PM

Gauge is from Greengauges and so is sender, so should be matched.
Going to have another play.