Fuel Gauge

[Kevin Smith]

hi,
I have installed a new Fuel tank (below deck) Alluminum, and a new fuel senser. Gauge is new as well.
I can not get the fuel guage to register anything at all. My trouble is with the connections. If I were to start over with a power and ground near by, can someone identify where the wiring configuration?

 

[hard-3]

Re: Fuel Gauge

check to make sure the sending unit has a good ground connection. measure with ohm meter from sending unit to engine to make sure it is o ohm resistence. check voltage going to gauge to see if 12 vt wire off of gauge going to sender gauge should read all the way off scale. ground wire going to sender should make gauge go off other side of scale.

 

[Silvertip]

Re: Fuel Gauge

Can't make it any simpler than this.

 

[livethedream]

Re: Fuel Gauge

hi guys,

could i jump in here with a question on fuel gauges?

my fuel gauge always reads past full, so i bought and installed a new teleflex sender and its properly grounded and connected to the sender prong on the gauge. didn't fix the problem.

when i have the sender out of the tank to test with the multimeter, it correctly reads 35 ohms full and 240 empty.

now the gauge is original (2000) and i'm suspecting it has a ground problem inside it. is there a way I can test the gauge itself to know before I spend money replacing it?


edit: woops, with further searching i found the answer... http://forums.iboats.com/showthread.php?t=268972&highlight=test+fuel+gauge

 

[livethedream]

Re: Fuel Gauge

ok, the gauge passed both those tests and the sender passed the tests, and the wiring is correct. i double checked my wiring and all is good...

S on sender to S on gauge
I on sender to ground plate on transom
I on gauge to ignition
G on guage to ground

any helpful thoughts?

 

[Silvertip]

Re: Fuel Gauge

I question your use of the term "I on gauge to Ignition". Ignition in this case means +12V, not the magneto or ignition terminals. In this circuit the "I" terminal on the gauge should connect to the +12V terminal on any of the other gauges.

 

[fdmsiv]

Re: Fuel Gauge

Just as a test I would disconnect the I on sender to ground plate and run a jumper directly to the "-" battery post.

Is there anything else that is not working, maybe you have a bad connection to a bus or something.

 

[livethedream]

Re: Fuel Gauge

ok, just checked those points.

the I wire on the gauge does go to 12v line that feeds the other gauges, and does have 12v according to the meter.

also did a direct ground wire from the -ve post on the sender to the -ve post on the battery, and no change.

i'm lost...

 

[Silvertip]

Re: Fuel Gauge

I have seen fuel senders that work fine out of the tank but not when they are in the tank. There are two reasons for this. 1) the float arm is too long and hangs up on an internal baffle or against the side of the tank. 2) The sender itself is defective (intermittent). Remove the sender from the tank, leave everything connected, turn on the key and move the float manually while observing the gauge. If it works normally, you have an interference problem.

 

[livethedream]

Re: Fuel Gauge

i've pulled the sender out and moved the float and the gauge stays at the over full mark, but at the same time with the mmeter the sender is reading the correct ohms.

i've tried a direct sender wire, a direct ground wire, there's power to the gauge... i don't know what else could be wrong. Unless the stock gauge is a different ohm range?

the sender instructions say that if the gauge reads constant full there's a short to ground but i've run new grounds with no effect.

 

[Silvertip]

Re: Fuel Gauge

Disconnect the send wire either at the gauge or the sender. This represents a high resistance to the gauge and it should drop to "E". If it doesn't, you have a short between the "S" terminal to ground at the gauge, or the "Sender" terminal to ground on the sender. Also, you cannot have power applied to a circuit that you have an ohmmeter connected to. Resistance measurements ALWAYS need to be measured with power OFF. Having a meter connected to the circuit essentially parallels the existing circuit. This essentially cuts the circuit resistance in half so the gauge would sense lower resistance and peg the needle. You have something shorted or miswired regardless of the fact you think it's right.

 

[livethedream]

Re: Fuel Gauge

right, when the sender wire is disconnected it does drop to E, and ohm readings were taken with power off.

I'll run complete new wiring and see what happens.