Fuel Sender Resistance

[vex]

Hunting for fuel level gauge and need to know the ohm range and correlation to full and empty.

[NoDOHC]

I should be home to test this for you on Thursday. I don't know off the top of my head.

If you don't get a reply by then, I will get you the info (should be in a sticky somewhere - sensor specs on a 2nd gen, 3rd gen, etc.

[vex]

I thought so too... I even tried checking out the www.rotorwiki.org, but it seems like it's offline!

[JerryLH3]

For the stock fuel gauge?

The 1991 FSM lists 7 ohm when full, 32.5 ohm at half, and 95 ohm when full.

EDIT: The above values are what it lists for the gauge itself. For the in-tank fuel level sender it lists, 3 ohm, 33 ohm and 110 ohm for those same three values.

[Pete_89T2]

Originally Posted by JerryLH3

For the stock fuel gauge?

The 1991 FSM lists 7 ohm when full, 32.5 ohm at half, and 95 ohm when full.

EDIT: The above values are what it lists for the gauge itself. For the in-tank fuel level sender it lists, 3 ohm, 33 ohm and 110 ohm for those same three values.

FWIW, the '89 FSM lists the same info on pages T-39 - T-40, "Body Electrical System" chapter. BTW, there's a typo above - the 95 ohms for the gauge is when it's on empty.

[vex]

What page number did you find that information on? I checked the FSM for the S4 and didn't see it (I don't personally believe they would have altered the resistance between the two).

[JerryLH3]

This is on page T-50 and T-51 of my 1991 FSM.

[vex]

I can't find a similar numbering convention on the FSM for the S4. What section did you find it in? I've checked the fuel and emissions section and didn't see it. Nor did I see it in the engine electronics.

[My5ABaby]

Originally Posted by vex

I can't find a similar numbering convention on the FSM for the S4. What section did you find it in? I've checked the fuel and emissions section and didn't see it. Nor did I see it in the engine electronics.

As I recall the S5 FSM is much better than the S4.

[JerryLH3]

Whoops. I did indeed mis-type that. The last value is empty.

[vex]

Found it in the S4 FSM:
Body Electric: 15-30 15-31
Sender Resistance: 3ohm Full, 32.5ohm Half, 110ohm Empty
Gauge Resistance: 7ohm Full, 32.5ohm Half, 95ohm Empty

So now the question becomes can a 90/0 gauge work?

[Pete_89T2]

Originally Posted by vex

Found it in the S4 FSM:
Body Electric: 15-30 15-31
Sender Resistance: 3ohm Full, 32.5ohm Half, 110ohm Empty
Gauge Resistance: 7ohm Full, 32.5ohm Half, 95ohm Empty

So now the question becomes can a 90/0 gauge work?

This should would work, if 90/0 corresponds to empty/full. Needle might be a little off the marks, but not likely enough to matter. Keep in mind the stock wiring will add a couple of ohms series resistance to the circuit, so you're pretty close to the stock figures.

[My5ABaby]

You can always add a resistor into the wiring.

[Sharingan 19]

Or just make a custom gauge cluster setup....

Honestly THIS is one of the main reasons I made my setup. I figure why go through all the hassle to still have a stock fuel tank and replace one of few stock parts that works w/o issue. Might as well have something that looks cool if you like wiring.

[vex]

Originally Posted by Sharingan 19

Or just make a custom gauge cluster setup....

Honestly THIS is one of the main reasons I made my setup. I figure why go through all the hassle to still have a stock fuel tank and replace one of few stock parts that works w/o issue. Might as well have something that looks cool if you like wiring.

lol, you mean something like:

+