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1988 Toyota Camry - Car stumbles when fuel is low

I have an 88 camry le 4 cylinder and each time the fuel level reaches one quarter or less, so right before the orange low fuel warning light comes on, the car starts to hesitate and stumble upon accelerating from a stop. Keeps getting worse as the fuel level continues to drop and by the time the light does come on, it feels like it is running on fumes and almost always ends up stalling unless i give it a ton of gas to try to make it to the gas station! Once i fill up the tank it runs perfectly without a hitch. This is not normal and is not safe since it is very unpredictable exactly when it will happen as these gas gadges are notoriously inaccurate to begin with. It shouldnt do this at a quarter of a tank. Btw, i do know that the fuel pump, gas tank, and fuel filter were replaced recently in the last year and it didnt do this with the original tank and pump. I trust my mechanic when he told me that i needed to replace all of these components but the bill was surprisingly low for the amount of work and parts that were replaced. Do you think he ordered cheap knock off parts from china or is it just that the fuel gadge sending unit might be out of calibration? Thanks. Any advise would help.

Why not just refuel at the 1/2 mark until this trusted mechanic can solve this problem ? I just don’t understand people who wait until the low fuel light comes on.

Having a 1/2 full tank might be a good thing if another massive power outage hits.

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Here is what I would do: at the first sign of any stumbling, I would do a complete fill up, and pay attention to exactly how many gallons of gas it takes, along with precisely noting the gas gauge position. I think it is likely that the gas gauge and idiot light are not properly calibrated. That is, it may be indicating 3/8 full when it is really nearly empty. Thereafter, I would just fill the tank when the gauge is between 3/8 and 1/2.
This calibration issue probably indicates a mismatch between the new tank and the new fuel pump. There is no point in spending more money to fix this UNLESS the system acts in a variable way. (I also never wait until the idiot light comes on before I fill up.)

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Hey Dauntless,
A million years ago my parents were crazy enough to buy me a used Toyota Supra. I lived through it, but crashed it head-on twice. Anyway, shortly after I got it, I was driving and it started to stumble and then shut off. It turned out that it was out of fuel at just under a quarter tank. It was a very expensive fix because the fuel system was contaminated with gunk (or so the mechanic told me). I had to replace some parts. Fuel injectors I think. My point is, don’t let it get so low and get it checked out before you find yourself in the same position I was back in the '80s.

Very clearly this is the issue. The pump’s fuel pickup tube is not low enough in the tank not to starve it when it gets to 1/4 tank.

Do NOT continue to drive the car like this, you will ruin the pump.

Either have your mechanic pull the pump and adjust the pickup tube, replace the pump with the correct one or never let your tank go below 1/2.

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The next time this starts happening, go to a quiet location, open the gas cap, and listen for air being sucked in. If that happens, come back here and tell us.

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Lion9car is getting at this: there’s no air being let into the gas tank. As the fuel gets pumped out, the fuel pump has to work harder and harder.

There’s a problem with the EVAP system, which prevents gasoline fumes from getting in the air but allows a little air into the plumbing of the fuel system. Fix that and you’re good to go all the way to empty if you want to!

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The fuel pump is weak.

When the tank is full, the level of gas in the tank creates a pressure head.

This pressure head assists the weak fuel pump in delivering the the proper pressure and volume of gasoline to the injectors.

As the level gas in the fuel tank drops, this pressure head decreases. Until deceases to a point where it’s longer assisting the weak fuel pump.

Have the fuel pressure tested when the car starts acting up. And I bet they’ll find the fuel pressure is below spec.

Tester

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@Tester is the most correct. It is not the gas cap or the vent system. If the tank were not venting, the problem would be worse with a full tank of gas as there would be less volume of air to expand and a vacuum would develop much sooner.

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t first I liked Tester’s answer about the additional pressure created by the head of gas in a full tank. The head of one foot of gasoline is only about 0.3 psi, so that won’t change the output pressure significantly. However, if the input flow is restricted, that flow would be regulated by the head pressure, with the symptom appearing as a weak pump. I believe the Camry has a fuel strainer on the input side which may be partially plugged. I note that fuel pumps are cheap, so maybe replacing both would be a good idea. All this means that the issue of a plugged strainer should be examined more closely.

This is important information.

Welcome…
Let us know what you come up with!

Good advise!

Fuel tanks in the 1980’s had a reservoir in the tank for the fuel pump to remain submerged in fuel while accelerating and turning corners. If the wrong tank was installed, the engine will stumble frequently when the fuel level is below 1/4 tank.

Where is it mentioned a new tank was installed??

The above is in the first post in this conversation.

If the pump was replaced as part of module it could be that the new sending unit for the gas gauge on that module has a different resistance reading; either due to the sender or the connector.
That in turn could cause the gauge to read higher than it did before while having less fuel in the tank.

Went through that recently on my Sonoma after replacing the pump module. Gas gauge acts totally different now by dropping a quarter tank in 75 miles along with having 5 gallons left when the Low Fuel light illuminates.