1995 Acura Integra Fuel guage innacurate

1995 ACURA INTEGRA
139,000 MILES • 4 CYL • 2WD • AUTOMATIC
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Z100JOJO
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My fuel guage reads 1/4 fuel when empty and pegs way past F when full. My low fuel indicator does not light and the bulb is verified good. Pretty obvious I have an issue with the send unit. My question is multi-parted. Since the unit is working accept for this particular anomaly, is it possble it's been contaminated with sediment and can be cleaned, and thus recalibrated to normal? How difficult is it to get to the send unit in my vehicle? This is a 3 door hatchback. Is it accessible thrue the hatch or is it under the vehicle? Must the tank be dropped?

Thanks.
Jul 12, 2008 at 10:50 PM
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KHLOW2008
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Hi z100jojo,

Since the gauge is working, the calibration has gone off, it can be calibrated, but the low fuel warning cannot be calibrated or cleaned, so you need to replace the unit.

You can access the sending unit through the service hole by removing the rear seats.
Jul 14, 2008 at 8:21 AM
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Z100JOJO
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Thanks for the reply. This of course has spurred a couple more questions.

1. Any precautions that I should take when accessing the send unit so as not to create a dangerous situation while working so close to the fuel tank?

2. what is the roceedure for re-calibrating the send unit.

3. Wouldn;t it logically follow that the fact the send unit is so far off that it shows 1/4 tank on empty also be the reason the low fuel indicator isn;t coming on, or does the calibration of one have nothing to do with the other?
Jul 17, 2008 at 2:23 AM
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KHLOW2008
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Hi z100jojo,

When working with fuel system, the most important factor is to do it in a well ventilated area and keep naked flames or sparks out of the way. Keep all car doors open.

DO NOT test fuel pump by connecting wires that could produce sparks if it is taken out of the fuel tank.

The 1/4 might be the correct reading, I have yet to see any sending units out of calibration so perfectly. When fuel tank is full, it would show past the F mark.

The possible reason I can think of when you have run out of gas when the gauge is at 1/4 is the fuel pump strainer is faulty, it could be broken or detached.

To calibrate the sending unit, you need to know its lowest and highest resistance.

The low fuel warning indicator sensing unit uses a separate circuit so is not related to the gauge reading.
Jul 17, 2008 at 9:31 AM
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Z100JOJO
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Actually, that's exactly what happens. When the tank is full the needle is pinned all the way right, and is way higher than F.
Jul 17, 2008 at 6:51 PM
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KHLOW2008
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Hi z100jojo,

There is nothing wrong with the full tank indicator.

If the fuel runs out at 1/4, check the fuel pump strainer first, it might be leaking or detached from the pump. That would require more fuel to be in tank for the pump to be able to reach.
Jul 18, 2008 at 12:11 AM
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Z100JOJO
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OK, finally pulled the fuel pump. No issue with the screen. Everything is 100% normal.

In a previous response you were telling me I need to determine low and high resistance for calibrating the fuel pump guage. Exactly how do I go about doing so and once determned, how would I go about the task of physically calibrating it?

Also, you indicated that the low fuel light is a separate circuit. Where is it and how do I service it to work again?

Lastly, since there's no obvious float device on the fuel pump assembly, how does this unit determine the level of fuel in the tank?

Thanks.
Feb 22, 2009 at 4:31 PM