Fuel Sender Resistance

vex · 01-25-2011, 09:47 PM

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

NoDOHC · 01-25-2011, 11:20 PM

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 · 01-25-2011, 11:46 PM

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

JerryLH3 · 01-26-2011, 09:00 PM

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 · 01-27-2011, 02:54 PM

Quote:

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 · 01-26-2011, 09:43 PM

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 · 01-26-2011, 11:20 PM

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

vex · 01-27-2011, 01:58 PM

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 · 01-27-2011, 02:45 PM

Quote:

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 · 01-27-2011, 04:00 PM

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

vex · 01-27-2011, 08:54 PM

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 · 01-28-2011, 06:40 AM

Quote:

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 · 01-28-2011, 09:13 AM

You can always add a resistor into the wiring.

Sharingan 19 · 02-03-2011, 02:25 PM

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 · 02-03-2011, 02:39 PM

Quote:

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:

+

01-25-2011, 09:47 PM	#1
vex RCC Loves Me Not You Join Date: Jul 2008 Location: Influx. iTrader: (6) Posts: 2,113 Rep Power: 19	Fuel Sender Resistance Hunting for fuel level gauge and need to know the ohm range and correlation to full and empty. __________________ The Official FC Radiator Thread My Project Thread: Cerberus CCVT Virginia Rotary Group

01-25-2011, 11:20 PM	#2
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin iTrader: (1) Posts: 855 Rep Power: 17	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. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)

01-25-2011, 11:46 PM	#3
vex RCC Loves Me Not You Join Date: Jul 2008 Location: Influx. iTrader: (6) Posts: 2,113 Rep Power: 19	I thought so too... I even tried checking out the www.rotorwiki.org, but it seems like it's offline! __________________ The Official FC Radiator Thread My Project Thread: Cerberus CCVT Virginia Rotary Group

01-26-2011, 09:00 PM	#4
JerryLH3 Rotary Fan in Training Join Date: Jun 2010 Location: Tampa, FL iTrader: (0) Posts: 40 Rep Power: 0	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. __________________ Jerry 1991 Mazda RX-7 Turbo - the current project/money pit Last edited by JerryLH3; 01-26-2011 at 09:13 PM.. Reason: More info I missed

01-26-2011, 09:43 PM	#6
vex RCC Loves Me Not You Join Date: Jul 2008 Location: Influx. iTrader: (6) Posts: 2,113 Rep Power: 19	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). __________________ The Official FC Radiator Thread My Project Thread: Cerberus CCVT Virginia Rotary Group

01-26-2011, 11:20 PM	#7
JerryLH3 Rotary Fan in Training Join Date: Jun 2010 Location: Tampa, FL iTrader: (0) Posts: 40 Rep Power: 0	This is on page T-50 and T-51 of my 1991 FSM. __________________ Jerry 1991 Mazda RX-7 Turbo - the current project/money pit

01-27-2011, 01:58 PM	#8
vex RCC Loves Me Not You Join Date: Jul 2008 Location: Influx. iTrader: (6) Posts: 2,113 Rep Power: 19	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. __________________ The Official FC Radiator Thread My Project Thread: Cerberus CCVT Virginia Rotary Group

01-27-2011, 04:00 PM	#10
JerryLH3 Rotary Fan in Training Join Date: Jun 2010 Location: Tampa, FL iTrader: (0) Posts: 40 Rep Power: 0	Whoops. I did indeed mis-type that. The last value is empty. __________________ Jerry 1991 Mazda RX-7 Turbo - the current project/money pit

01-27-2011, 08:54 PM	#11
vex RCC Loves Me Not You Join Date: Jul 2008 Location: Influx. iTrader: (6) Posts: 2,113 Rep Power: 19	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? __________________ The Official FC Radiator Thread My Project Thread: Cerberus CCVT Virginia Rotary Group Last edited by vex; 01-27-2011 at 09:19 PM..

01-28-2011, 09:13 AM	#13
My5ABaby Sigh..... Join Date: Feb 2008 Location: Murfreesboro, TN iTrader: (6) Posts: 2,377 Rep Power: 19	You can always add a resistor into the wiring. __________________ 1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles Community Service Manual RotorWiki "Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."

02-03-2011, 02:25 PM	#14
Sharingan 19 Rotary Fanatic Join Date: May 2010 iTrader: (0) Posts: 138 Rep Power: 15	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.