Fuel gauge accuracy problem
11-12-2001, 01:52 PM
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Fuel gauge accuracy problem
Hello, I'm new to this forum and I'm glad to see the members are so knowledgeable. I am having a problem with my fuel gauge; when I fill the tank (to the point where the nozzle clicks off) the gauge only reads ¾ tank. It takes some time for the gauge to finally move so I'm assuming that it's a problem with the float in the tank. Any suggestions? Is it the float, just a sensor, the gauge itself? Please say it's something inexpensive 
11-12-2001, 02:10 PM
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Mo ; this is a very common problem with all models and yrs of the 924/ 944 series. I have found it to be the tank sending unit most of time. The problem is caused by gas residue build up. (the white ,hardened , caked stuff you find on parts that are gas soaked ). The solution is to remove the unit and just turn it up side down a few times to break the residue that is caked on in the inside of the alum tube.Make sure when you reinstall it that you get the tube to go on the tank baffle ring( the doughtnut, which will be left inside the tank, ) and seat it correctly in the tank. HTH 
11-13-2001, 01:46 PM
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Mo; no , but it makes it easier to see the seat and doughtnut.REMEMBER ,SAFETY FIRST , YOU ARE AROUND GAS. Also the gauge could be off from the factory , contact me at emilysgranny @ aol.com and I will explain how to fix this.
11-13-2001, 04:32 PM
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Same here,
As for safety first, any special precations need be taken? No smoking is obviously number one. Also, does the low fuel light work off of the gauge or is it another sensor? Thanks,
As for safety first, any special precations need be taken? No smoking is obviously number one. Also, does the low fuel light work off of the gauge or is it another sensor? Thanks,
11-13-2001, 05:37 PM
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Granny,
If your gonna write out the details, please write them here. My 3/4 full-full has been bugging me since I got the car. I figured it was that way from the factory.
Now when I decide to attack all the little jobs (cruise cable per perry's fix, H2O from a/c, and now gas guage) I'll have a good day's work.
Thanks in advance!
If your gonna write out the details, please write them here. My 3/4 full-full has been bugging me since I got the car. I figured it was that way from the factory.
Now when I decide to attack all the little jobs (cruise cable per perry's fix, H2O from a/c, and now gas guage) I'll have a good day's work.
Thanks in advance!
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11-13-2001, 06:34 PM
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I know it is attacking the symptom and not the problem, but an old hot-rodder solution is to run the tank empty, then bend the needle to empty. Or if you would rather set it to full that works too... just a question of what you want your absolute to be. I have been thinking about doing just that on my car... this 1/4 off stuff drives me nuts.
Firestarter
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11-13-2001, 06:53 PM
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Firestarter,
Do you think the gauge is ¼ tank inaccurate all of the time? I'm not sure mine is inaccurate at the "empty" side of the gauge, but I'm not willing to run it to failure to find out. When I fill up it sits at ¾ tank for some time and I was under the impression that it just wasn't getting enough of a signal to read "full"; then as the fuel is consumed the gauge stays pegged (so to speak) at ¾ until the level drops below that level and then the gauge starts reading appropriately. Is there a run-on sentence in there somewhere? If Emilysgranny's repair suggestion works then it would confirm my suspicions, if not then I'll have to use the other fix.
I don't want to bend the needle so if I have to choose the accuracy of the gauge's extremes I'd rather have the "empty" side accurate. I don't like running out of gas.
Do you think the gauge is ¼ tank inaccurate all of the time? I'm not sure mine is inaccurate at the "empty" side of the gauge, but I'm not willing to run it to failure to find out. When I fill up it sits at ¾ tank for some time and I was under the impression that it just wasn't getting enough of a signal to read "full"; then as the fuel is consumed the gauge stays pegged (so to speak) at ¾ until the level drops below that level and then the gauge starts reading appropriately. Is there a run-on sentence in there somewhere?
If Emilysgranny's repair suggestion works then it would confirm my suspicions, if not then I'll have to use the other fix.I don't want to bend the needle so if I have to choose the accuracy of the gauge's extremes I'd rather have the "empty" side accurate. I don't like running out of gas.
11-13-2001, 07:07 PM
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Mo , Tom H, Scott,Firestarter ; If you have no reading at all at the gauge, try this to isolate the problem. PLEASE DON'T FORGET WE ARE WORKING AROUND GAS. Disconnect the plug from the sender in the tank and jumper it . your gauge should now get a reading .You now know if it is the sender at fault or the gauge or an electrical problem.If your reading is off , you can remove the cluster from the dash carefully attending to the wiring harness clip as these break easily.Remove the clear plastic cover and the needles will be accessible . These indicator needles are molded on to the center pins of each gauge. Gently turn the needle on the pin to the difference you noted as being off in your every day driving.Your set, just put it back together.Incidently if the clear plastic cover is scratched this is the time to polish out the scratches with some fine grit paper 800-1000.ut oh, dinner is ready ,be back in a while to finish post.Sorry guys .
11-13-2001, 08:52 PM
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Granny: How does that sender work ?? I just looked at a drawing of the sender, and it is different from senders I have seen on other cars. The drawing showed a large diameter tube, fitting into the top of the tank, but no details.
11-14-2001, 01:25 AM
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I would love to see the procedure to remove and clean the fuel gauge sender. Mine reads FULL sometimes when I fill it up and 3/4 the other times. Also, does anyone know why my LOW FUEL light doesn't work? I replaced the bulb with a new one and no luck. Also cleaned all the contacts on the instrument cluster. 
11-14-2001, 04:19 AM
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Hi Guy's
Am sure you found these links below: http://www.pelicanparts.com/techarti...er_replace.htm
http://www.pelicanparts.com/944/944_...-85/Pic161.jpg
As per Emilysgranny's post, it is most probably corrosion / built up on the sender unit. Cleaning it should cure the problem.
There has been a thread on the resistance values the sender unit should have on various levels some time ago.
Do not know if this thread is "vaporised" in the hard disk crash, but checking the archives / history might be advisable.
Take care
Am sure you found these links below: http://www.pelicanparts.com/techarti...er_replace.htm
http://www.pelicanparts.com/944/944_...-85/Pic161.jpg
As per Emilysgranny's post, it is most probably corrosion / built up on the sender unit. Cleaning it should cure the problem.
There has been a thread on the resistance values the sender unit should have on various levels some time ago.
Do not know if this thread is "vaporised" in the hard disk crash, but checking the archives / history might be advisable.
Take care
11-14-2001, 09:49 AM
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Modus,
The first thing I do when I acquire a new-to-me vehicle is check the accuracy of the fuel gauge. I fill a small fuel tank with gas and put it in the car. I have found in the 944 that a 2.5 gallon tank fits nicely in the passenger side rear wheel well. I then simply drive until I get one sputter. I find that from when my low fuel light comes on, that I have another 70 miles before I run out of gas. I also noticed that once the needle reaches "R" it stops its descent. I assume then that "R" is where the tank is supposedly empty, however, my vehicle can go almost 200 miles from when I first hit "R". Therefore I deducted that the entire gauge has 1/4 shift and that bending the needle would in fact work to reset the gauge.
Also note that when I say bending the needle, it doesn't really bend the needle. If you ever take a gauge apart, the needle is driven by a small bundle of wire. I do not see any way in which one could damage by bending the needle only this small amount.
Firestarter
The first thing I do when I acquire a new-to-me vehicle is check the accuracy of the fuel gauge. I fill a small fuel tank with gas and put it in the car. I have found in the 944 that a 2.5 gallon tank fits nicely in the passenger side rear wheel well. I then simply drive until I get one sputter. I find that from when my low fuel light comes on, that I have another 70 miles before I run out of gas. I also noticed that once the needle reaches "R" it stops its descent. I assume then that "R" is where the tank is supposedly empty, however, my vehicle can go almost 200 miles from when I first hit "R". Therefore I deducted that the entire gauge has 1/4 shift and that bending the needle would in fact work to reset the gauge.
Also note that when I say bending the needle, it doesn't really bend the needle. If you ever take a gauge apart, the needle is driven by a small bundle of wire. I do not see any way in which one could damage by bending the needle only this small amount.
Firestarter
11-14-2001, 10:18 AM
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Firestarter,
I like your technique for calculating the accuracy of the gauge. I misunderstood when you said "run the tank empty", all I saw in my head was empty fuel lines and a fuel pump plugged with the garbage from the bottom of the tank; but you stop the car before it totally runs out of fuel. Once I clean the sender I'm going to try your calibrating technique, it's always good to know how far you can push the car past Empty (knowledge is power).
I like your technique for calculating the accuracy of the gauge. I misunderstood when you said "run the tank empty", all I saw in my head was empty fuel lines and a fuel pump plugged with the garbage from the bottom of the tank; but you stop the car before it totally runs out of fuel. Once I clean the sender I'm going to try your calibrating technique, it's always good to know how far you can push the car past Empty (knowledge is power).