Hi girls and gals .its me again

the problem I am haveing is my gas guage is wrong .I do know there are 2 sunding units and I know how to get to them .the left one has the most wires on it and the right one has 2 wires ..when I checked the right one (both wires) to see if there is 12 volts going to it .there wasent .so I got ouy my multi meater and got .01 I think if I can reamber .with the tank full .when the gas gauhe is on empty i still got 100 miles to go .so if there is any ideas .please let me know ..97 legacy sadan thanks so much

http://www.ultimatesubaru.org/forum/showthread.php?t=96389

 

start here, search is our friend

hello search your doing good ...lol thanks I am going to try that tectron fuel add. Thanks

Hi girls and gals .its me again

the problem I am haveing is my gas guage is wrong .I do know there are 2 sunding units and I know how to get to them .the left one has the most wires on it and the right one has 2 wires ..when I checked the right one (both wires) to see if there is 12 volts going to it .there wasent .so I got ouy my multi meater and got .01 I think if I can reamber .with the tank full .when the gas gauhe is on empty i still got 100 miles to go .so if there is any ideas .please let me know ..97 legacy sadan thanks so much

 

Its a subaru, they do that. We consider those to have accurate gas gauges to be "wierd" and outsiders

 

Learn to rely more on the trip odometer and the low fule light, though there is nothing wrong with filling up on E at 10 gallons. Imagine filling up on E and it taking 18 gallons, THEN you would worry (especially when they only hold 15.9).

 

 

nipper

no thanks nipper i will fix the problem .as I do on every thing i do fix fix fix .gota love it ..

Its a subaru, they do that. We consider those to have accurate gas gauges to be "wierd" and outsiders

 

Learn to rely more on the trip odometer and the low fule light, though there is nothing wrong with filling up on E at 10 gallons. Imagine filling up on E and it taking 18 gallons, THEN you would worry (especially when they only hold 15.9).

 

 

nipper

 

Yea I know, I am that one wierd one :-p:brow:

Add me to the weird group. mike97, I did both sides on my ’97 L when my gauge went whacko. Now I didn’t try the Techron route but I did pull both units out, sprayed the contact points with contact cleaner, hit them with a pencil eraser; put them back in the car….and you know what…the gauge worked. As you have read, the left side comes out easily, the right side, with the fuel pump, you have to contort around to get it out and back in again. As it cost very little other than your time, it might be worthwhile.

May I ask how well those rubber gaskets resealed?

 

Last time I re-used them it was on a 94, they were dry, and I ended up having to replace them. ABout 30 bucks IIR.

 

If they worked well I'd be more likely to clean the contacts on the cars with moody guages.

I'm surrounded by wierdos.

 

When i had mine out of blue and the silver legacy (98 and 97) the gaskest were fine. I reused mine. I reused the ones in Blu several times.

 

 

nipper

lol nipper ....the gasget if it is any good witch i am assuming it is somewhat ok .I will reuse with some gasget maker should be fine mabie the high temp I have used that on rear end covers for my truck ..i will try all that ..thanks so much ..usmb rules the planet well almost subaru is on top .lol

You stated in your original post that you didn't have any voltage at the connection to the suspected bad sensor. You also didn't state how you tried to measure the voltage. If it was across the leads or with reference to ground. Regardless, it seems to me that you should have had some sort voltage reading there normally, even if there was a problem with the sensor inside the tank. So it sounds to me the trouble you are having, in part at least, is external to the tank. It appears there is a bad connection somewhere between that sensor and the gauge. There may be a problem with the sensor also but you will need to have voltage at the connection points. Try checking the resistance of the sensor leads to see if that is near the reading it should be. Isolate the leads to the sensor when you do that so you won't possibly get a false reading. Make sure there isn't a short across the leads or to ground.

You stated in your original post that you didn't have any voltage at the connection to the suspected bad sensor. You also didn't state how you tried to measure the voltage. If it was across the leads or with reference to ground. Regardless, it seems to me that you should have had some sort voltage reading there normally, even if there was a problem with the sensor inside the tank. So it sounds to me the trouble you are having, in part at least, is external to the tank. It appears there is a bad connection somewhere between that sensor and the gauge. There may be a problem with the sensor also but you will need to have voltage at the connection points. Try checking the resistance of the sensor leads to see if that is near the reading it should be. Isolate the leads to the sensor when you do that so you won't possibly get a false reading. Make sure there isn't a short across the leads or to ground.

 

 

 

i tested the units with a test light 12 v just to see if there was any on the left side there was one wire with juice .thats the side with more wires .on the right side i tested it with a test light and no juice .2 wires .then I used a muti meater and I could not get a good reading becuse the tank was full.so today I am takeing them out and cleaning and testing everything .thanks

Using a multimeter to measure the voltage is a better way to test this circuit. It won't load the circuit down like the light will. Another thing; to me it shouldn't matter if the tank is full, empty, of something in between. You should have some sort of voltage across both of the sensors at all times.

 

I recently found out that the fuel level sensors are wired in series with each other. Does at least one of the wire colors match on each of the sensors. If so, check the resistance between that wire. There may be a break in it. Also try measuring the resistance across the sensor with two connections on it.

You should have some sort of voltage across both of the sensors at all times.

 

dummy question for electrical experts, can you have resistance on a circuit with out voltage? could the guage be looking for resistance with no real voltage being present??

I have attached the wiring diagram from the FSM for my '97 L. I will let the electrical wizards decipher the meaning(s) of all those black lines. Also, I remember when I was bench testing the sending units, there were values assigned for the position of the float relative to the amount of fuel. I can't find the values, but remember the closer you got to full, the less resistance was generated. Can anyone update with the correct values.

dummy question for electrical experts, can you have resistance on a circuit with out voltage? could the guage be looking for resistance with no real voltage being present??

 

Some current has to flow through any circuit for it to work and thus there will be a voltage drop across any resistance in that circuit. Ohms Law must prevail.

Hats off to Yohy for posting the diagram. Thank you.

 

Looking at the drawing you can see that pin 3 of the connector also ties to pin 2 of the other sensor. Check to see if there is voltage between pin 3 and ground. You should have some there from what you stated earlier. Then move the probe from pin 3 to pin 2. You should see the same voltage there also. If you don't then the wire between the sensors has a break or bad connection.

 

Actually, the drawing shows pin 1 is the high or supply side of the sensor elements so you should see the highest voltage there.

Edited March 14, 200917 yr by Cougar