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2001 Honda Civic EX try for help #2

Well I posted a couple of days ago and have only gotten one somewhat relevant response, so I’m trying again:

My 2001 Honda has only 33,500 miles on it but I think it’s cursed by the lemon gods. Aside from having been t-boned on each side, and the whole outer structure having to be replaced (aside from hood, roof, and trunk), I’ve had this annoying problem that occurs when my tank has 1/3 or less gas in it. When the tank is full or above 1/3, it seems fine, runs great. But when it falls below 1/3, it starts to miss and jerk/hesitate when I accelerate. My check engine light went on when this first started happening and the code says it’s running lean (code PO171, system too lean, bank 1).

When this first started happening (over 2 years ago) I took it to one of the local dealers. I took it in 3 times. Each time they couldn’t figure out what was wrong; once they replaced the oxygen sensor and the other times they just added something to the fuel (like a cleaner). The check engine light would go off for maybe a week and then it would go on again and the original problem was still there even after they replaced the oxygen sensor.

So it’s time for me to go to DEQ and to renew my registration, but I can’t pass DEQ unless the check engine light is off. I could probably have the dealer temporarily turn it off, but I’d rather figure out what the problem is and get it fixed. Has anyone ever heard of this problem? What do I do?

Friends have suggested that maybe it’s the fuel filter or the fuel pump but wouldn’t this problem happen all the time, then? I’d like some more assurance about what’s wrong with this thing.

Help!! And thanks!

It sure would, and it has been happening all the time. Whenever you get below 1/3rd of a tank. Usually below 1/4th of a tank is critical for fuel pumps. If you have a four cylinder engine, bank one is all you have. You did not say how many cylinders your engine has. Not in this post anyway. It should be possible to test the fuel pump, shouldn’t it? A lot of mechanics will let you guess the problem because they don’t dare to suggest it or show any willingness to actually test things. It’s bad that customers are left needing reassurace from fellow guessers. You have the same symptoms as an empty fuel tank / bad pump / clogged filter.

Thank you, that is helpful! I do have a 4 cylinder engine, manual transmission. I will find out if it’s possible to test the fuel pump. Someone told me that the fuel filter for my car is located in the gas tank and that it would be very expensive for a mechanic to get in there and check it out…that seems ridiculous.

A “certified technician” answered another post I made on another site and suggested that I may want to consider dropping the gas tank to inspect the pick-up assembly to see if it is intact or bent, possibly due to a broken hose that has to be submerged to create the proper fuel pressure. Since I’ve been in 2 fairly major accidents, maybe that’s a good guess.

I feel like I do when I go to see the doctor…I end up having to tell them what needs to be tested rather than them knowing from their experience!! But I’d rather gather all possibilities and then the mechanics can try out the options.

If that is the original fuel filter, you should replace it. It would, then, no longer get consideration as a suspect.
We can’t give you a silver bullet…there are too many checks and tests to perform.
When a component, or function, is suspect, checks and tests are done on that to prove or refute the suspicion. For example, the fuel pump is suspect. OK, test it. Test it at idle, under load, for an extended period of time (long enough to dissipate the initial pressure build up).
Some auto parts stores will read, and erase, the trouble code for you, for free. Just ask. If the trouble light stays off for several days, the computer will have time (if the car has made several “trips”) to complete its self-tests (monitors), and you should be able to take it through emissions test. You can try.
You need an able mechanical. Perhaps, your friends, and acquaintances can help you find one.

Auto Zone says the fuel filter is in the engine compartment for the 2001 Civic. Easy to find out for sure. Look!

The fuel level gauge indicates 1/3 tank, when the tank may, actually, be empty. When the fuel level indication gets to 1/3 tank, how many gallons does it take to fill the tank? What is the total capacity of the gas tank?

Thanks for your helpful info and suggestions. I will find out if a local auto parts store can erase the trouble code and then hopefully I can at least pass DEQ and renew my registration!

My car does have the original fuel filter and pump, so perhaps one of them is the culprit. Although I would have thought the dealership mechanics would have tested these components originally.

You make another good guess…I wish it were that the tank were empty and that’s why my car hesitates when it does, but it’s unlikely. My tank holds about 13 gallons of gas and I’m diligent about calculating my mpg every time I fill up (which is only about once a month, as I don’t drive very often or very far), which means I know how many gallons it takes to fill up the tank every time. The fuel gauge has been erratic in the past but I don’t think the tank is empty when it shows 1/3 or 1/4 left. When I’ve filled it up at 1/4, for example, it takes no more than 10 gallons. Typically I fill it up when it’s just below 1/2 because then it always runs pretty well.

My Mom found out the same medical thing. The bowel specialist will not find the cancer of the liver. When he said “it isn’t in my area”, she went to the doctor who could help.

Since you’ve been t-boned twice, you could very well have a problem with the fuel pump that will not be detected by a fuel pump test. The fuel filter is not likely the problem.

The pump could have partially separated from the hard fuel line that goes to it. The pump is located in the bottom of the gas tank and one of the hits could have caused a small crack in the hard line where it attaches to the pump. When the tank is full, the weight of the fuel around the line may be keeping the fuel pressure at barely acceptable levels. As the fuel level decreases, the weight also decreases causing the fuel pressure to decrease.

It is also possible that the gas tank has become deformed at the bottom near the fuel pump intake causing it to work harder to draw fuel, especially as the fuel weight decreases. You may also have a marginally performing fuel pump to begin with.

I understand Keith’s point about the hard plastic fuel line possibly cracking near the fuel pump. That crack could be at the 1/3 tank level.
When you took the car in for test and repair, before, was the tank at 1/3 level or less; and, was the check engine light on, then? This, when the symptoms are present, is the best time to check for the cause.
Could the 1/3 tank and the problem be co-incidence? Or, do they always occur together? This never happens when the level is above 1/3 tank? If never, you could defer repair forever, or a long time (whichever occurs first).
The wiring for the fuel level indicator and the fuel pump most likely share an electrical connector. The fuel level indication has, at times, in the past, been erratic, yes? I would like to have this wiring connector inspected, and the rest of the wiring at the gas tank, to be inspected for abrasions and cuts.

Geez, could either Keith or Hellokit come over to Portland OR and inspect my car for me? You both have such plausible hypotheses. The hesitation problem never happens when the tank is above 1/3 full, although I think my mpg has decreased. I would defer repair forever if the check engine light didn’t keep coming back on (and if I didn’t eventually want to get rid of this car and buy a hybrid).

If I’m going to have this checked out, clearly I need to wait until I have that lower level of gas in the tank because that’s when the symptoms show up. In the meantime I’m going to find out if I can get the check engine light turned off so I can pass DEQ and renew my registration.

Because I’ve typically had cars with few problems, I don’t know if it’s typical for repair shops to charge a base fee up front to explore and diagnose, and apply that fee to the repair costs. And what if they can’t find out what the problem is…do I have to pay for all that labor time if the problem doesn’t get solved?

You don’t expect a free diagnosis from your doctor, do you? Many shops will roll, at least part, of the original diagnosis fee into the rest of the repair cost, when you have them repair it. A good diagnosis can save you a lot of time and money that might otherwise be spent, in an experimental fashion (of parts replacement), in an attempt at repair.
An engine can have a lean condition for a number of reasons. Broadly, it can be lean when not enough fuel goes to the engine, or the fuel pressure is too low. A dirty fuel filter, or a weak fuel pump, or a “weak” fuel pressure regulator, can cause both conditions.
An engine can be lean when more unmetered air goes into the engine than a metered amount of fuel.
Since your problem only happens below 1/3 tank, the fuel pressure (with the engine under load for a couple of minuets—to use up any built up fuel pressure) should be measured. It should be measured at a tank level above 1/3, also.
You can’t just turn the check engine light off and go through the emissions test. The reasons are technical, but, yore car gone tell on you.
The dealer hasn’t been right for you. Take your car to an independent shop/mechanic. There, you’ll actually get to talk to a mechanic (the shop owner/operator is, often, a mechanic).

Your 01 civic doesnt have a replaceable fuel filter. It has a fine strainer at the fuel pump which is supposed to last the lifetime of the (…car?..fuel pump?..) It os one of Honda’s least great ideas, although somehow it seems to work. Rather than changing the fuel filter, simply adding fuel system cleaner is supposed to refresh it and eliminate the need to change.
That being said, your fuel filter isn’t your issue. Id lay odds that the fuel pump pickup hose is split or cracked about 1/3 of the way from the bottom. When the fuel level gets low, it starts pulling air through the crack.
To get a better read on the problem, buy an OBD scan tool with data logging abilities. (I prefer an elm327 bluetooth adapter with the torque app on an android phone) let the log run for a while and make note of where and when you have the issue, then compare that time to the other parameters stored by your computer. Im guessing that you will see a fuel pressure drop when your fuel level hits a certain level.

10 years to late.

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