Car Won't Start with Half Tank of Gas?

This is the second time happening to me. Last time was several months ago.The car literally won't turn over like there is no gas in the tank at all. Didn't pay attention last time but this time the fuel gauge was at 50%. So I poured in about 2 gallons of gas and was able to go to go gas station for another 6 gallon before it got full. Now the fuel gauge is at full. Seems like the fuel sending unit is good. Has anyone experienced similiar situation before? Maybe needs a new fuel pump or even fuel filter? Its a 92 with 60k miles.

I don't know much but sounds like some of the issues I've heard about with the main relay overheating it going bad.

If its main relay, it wouldn't start right up after adding gas would it? Seems like its unable to reach the bottom of the fuel tank or pump is getting weak? It is very odd.

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YOu know what, it could be main relay as fuel pump relay is also piggybacking on it causing a weak voltage to fuel pump. Wish i have a fuel pressure gauge to monitor. Might just have to remove the back panels for testing.

I had this happen on my old integra with hard starting at half a tank. Fill it up and the problem disappears.
I would check the fuel pump inside the fuel tank. There is a "sock" that absorbs the fuel and it probably fell off.

When this happens do you hear the fuel pump behind the drivers seat when you turn the key to "on" position for about 3-5 seconds?

its hard to troubleshoot since I went ahead drained all the fuel and no issue since then. What may have happened was that some fuel in the tank were whitish when i drained it. I suspected it was just bad gas. Its pretty odd considering I drove next to empty tank a while back just fine. anyway, I drained the whole tank and replaced with new v-power gas. havent seen an issue again. fuel draining was a PITA on jackstands. make sure you get a new crush washer or it will leak for sure.

its funny you say whiteish every tank I have drained has had whiteish sludge at the bottom of the tank I wonder if it the 10% ethanol crap they add

I call main relay. Mine was random and I associated it with fuel etc. Even my laptop/briefcase behind the seat pressing on the ecu. Changed the relay -no issues

When you're not absolutely certain of the cause of a problem, you try replacing parts that (a) fail most commonly, and (b) are inexpensive and easy to replace. The main relay qualifies on both counts. Replace the main relay, and there's a good chance it will fix the problem. And even if it doesn't, you can be confident that a new main relay should last a long time, so it's a good idea anyway.

The main relay costs around $60, and anyone with even a little bit of mechanical ability and a socket wrench can replace it himself. Just gently pry off the thin bolster at the top of the rear of the cabin (just below the window between the interior and the engine compartment), then it's just a bolt and a connector.

shawn110975 said:

its funny you say whiteish every tank I have drained has had whiteish sludge at the bottom of the tank I wonder if it the 10% ethanol crap they add

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Ethanol is hygroscopic (tends to absorb moisture from the air). This is normally not a problem if the water and ethanol remain suspended in the gas. However, if there is a significant drop in the ambient temperature, the water can come out of suspension in the ethanol forming, for lack of a more technical description, an 'icky' emulsion which will collect in a low spot in the tank (water having a higher SG than gas). Once out of suspension, the emulsion will stay out of suspension and tend to accumulate more ick if the conditions for coming out of suspension repeat.

The NSX has a sealed fuel system so there should not be a problem with the system accumulating moisture by exposure of the fuel to moisture laden air. However, it does sound like over a period of time of time you are accumulating enough moisture to suffer from phase separation. Where I live, we definitely get the temperature drops (it was around -30 C this morning) that will precipitate phase change if there is any water in the gas. Fortunately, most of the premium fuels sold in Western Canada are formulated without ethanol. Some of the fuel company websites provide details on their formulations. You may be able to find a fuel company that does not formulate with ethanol. Where I live, the fuel pumps generally have a sticker on the pump with such wording as 'may be formulated with up to 10% ethanol'. The local Shell and Petrocan premium blends are definitely missing those stickers.

Selecting a non ethanol premium fuel may help to reduce the accumulation of that whitish emulsion in the bottom of the tank. As a related note, I am not aware that fuel stabilizers are of any value in preventing the phase separation problem if there is moisture in the gas.

nsxtasy said:

When you're not absolutely certain of the cause of a problem, you try replacing parts that (a) fail most commonly, and (b) are inexpensive and easy to replace. The main relay qualifies on both counts. Replace the main relay, and there's a good chance it will fix the problem. And even if it doesn't, you can be confident that a new main relay should last a long time, so it's a good idea anyway.

The main relay costs around $60, and anyone with even a little bit of mechanical ability and a socket wrench can replace it himself. Just gently pry off the thin bolster at the top of the rear of the cabin (just below the window between the interior and the engine compartment), then it's just a bolt and a connector.

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And that is exactly why I ordered an extra new main rely months ago just in case. But I dont wanna replace it relay unless the issue arises again. I wanna be sure about the cause of the issue rather than replacing it anyway just because better safe than sorry. I also grabbed 3 main relays for my Legend a week ago. Main relays are pretty common issue among Honda and Acura.