Rep Power: 0

Howdy,

I have a manual '02 4-dr Civic Lx Sedan with 136,000 miles on it. With the exception of this problem (and some rattling at 2.5k rpm... probably a benign loose heat shield?), she runs like a charm.

So, here's my issue:
My gas tank won't fill all the way. A few weeks ago I was preparing for a 280mi road trip so I filled my tank. The fuel gauge said there was 1/4 of a tank left before I began to fill, but it took 12.4 gallons at the pump (i.e. the fuel gauge was reading a bit high). I was a bit perplexed, but didn't think much of it. That is, until I returned from my 280 mile trip and my fuel tank would only take 3 gallons, leaving around 5 or 6 gallons-worth of empty space. 5-6 GALLONS! After several tries to continue filling (only to be stopped by the auto-shut off) I gave up. Now I can only fill up what I use in gas (e.g. if I drive 35 miles, I can fill up 1 gallon of gas), leaving that remaining 5-6 gallons still empty. Weirdly, the gas gauge reads full, even after 80 miles of driving, and never drops below 3/4-ish.

I read some stuff on the internet about clogged air-outlets near the fuel-inlet, so I looked under the car, and, sure enough, there were two (very flexible) black rubber hoses running from the gas inlet (gas cap area) past what I think is the charcoal canister (but not connected to it) toward the gas tank-- one was about an inch in diameter and the other was about the diameter of a pencil. Both were secured with butterfly clamps, but nothing more. I unplugged them and, wahlah!, gasoline came out of both- about 3/4 a cup of new yellowish gasoline with a smal bit of white debris from the larger tube, and about 1/4 cup of old, orangish/blackish gasoline from the smaller tube. Both tubes are now completely clear... I'm pretty sure.

I figured this was the fix (hooray!), but I drove over to the gas station and the thing only took 2 gallons-- which would make sense because i recently drove ~ 80 miles-- but definitely didn't fill the tank. So, not the fix. And, the gas gauge still reads full.




I've searched the forums for an answer to this issue, but can't seem to find any (except maybe a busted charcoal EVAP cannister... but I hear those are expensive to replace, so I'm hoping there might be an alternative?).

I'd love to hear your thoughts!

 
Rep Power: 812

try and determine whether the tank is actually full and the gauge is reading the wrong amount, or if you physically cannot add fuel and there is empty space. i remember when my car was fairly new, the gas gauge was terrible. keep in mind our cars only have a 13.x gallon tank. i could sometimes go 100 mils before the needle dropped below the F line. and when the gas gauge read empty with the light on, there was still 5-6 gallons in the car when i went to fill up. turns out it was a faulty fuel sending unit that got replaced under warranty. never had a problem since then for 5 yrs. usually i get 50 miles before the needle drops, and when im at empty, theres only 1-2 gallons left. i recommend having the sender replaced. its kinda a big job, since it involves taking apart the fuel pump under the rear seat.

 
Rep Power: 0

Hey Gerabox, thanks for the response!

I'm 99.9% positive that there is physically empty space in the tank, as I drove about 300 miles after filling the tank with 12.4 gallons of gas, and was only able to refill it with 3 gallons. On top of that, I have since only been able to refill what I've used (e.g. driving ~35 miles allows me space for 1 more gallon).

Would a faulty sender keep me from actually filling the tank, or just make my gauge wonky?

Cheers!

 
Rep Power: 235

Per the manual: There are 2 lines going to Fuel Tank Vapor Control Valve (FTVCV). Pull those lines loose and if fuel comes out of either replace the FTVCV. Also pull the fuel tank vapor recirculation hose (the smaller one you pulled) and if fuel comes out replace the FTVCV. Note: tiny droplets of fuel are normal at either location.

I took the driver side rear wheel off to show you where it is. It's the roundish spotlighted part.

Here it is from the bottom:
The manual says the fuel tank has to be removed to replace the FTVCV. I think that's because they want you to relieve the fuel pressure so fuel doesn't come pouring out on you.

I would try:
1. Relieving fuel pressure via quick-disconnect

2. One at a time remove and plug each line leading to FTVCV

3. Slide the FTVCV out of the groove in the fuel tank and replace

4. Replace the 4 lines and the quick-disconnect

If you can't get the FTVCV out of the groove then remove the fuel tank and replace the FTVCV.

 
Rep Power: 235

To relieve fuel pressure:

1. Turn ignition to OFF

2. Remove this relay: It's behind the glove box.

3. Run the engine until it stalls.

4. Turn ignition OFF

5. Remove fuel fill cap

6. Disconnect negative battery cable

7. Disconnect the quick-connect fitting. It's behind the airbox in the engine bay. Here's a pic:

 
Rep Power: 0

Wow lazlong, thanks for putting so much effort into that post! I'll check it out and let you know how it goes.

 
Rep Power: 235

You were lucky today, I was bored. lol. Good luck.

 
Rep Power: 812

lazlong has the right idea, since the sender is only for the gauge reading. if you have empty space, there is a problem with the vapor system that is making the nozzle shut off. im sure you tried different gas stations already, but in case not, might be worth a try. i have bad luck with some pumps. sometimes gas overflows and spills out, other times it does not fill up to the F line. chevron always works for me.

 
Rep Power: 0

It sounds as if your sending unit in the gas tank is probably giving you faulty readings. Most likely, the float itself is faulty.

 
Rep Power: 235

If it was the float being stuck he could put more than 3 gallons in it.

 
Rep Power: 0

I'm sure you got your problem fixed by now (been 2yrs ago since your orig post). If not, when you fill up your fuel tank, reset your trip odometer. When you get over 250 miles, start looking for a gas station (your just below 1/4 tank left).

As for your gauge problem: You need to determine if it's an issue with the gauge on the dash or a problem with the float sensor inside the fuel tank. These 1996-1999 Civics have problems with the fuel tank floats getting leaks in them, and they become at least partially filled with gasoline (they QUIT floating on top of the gasoline inside the tank because of this, which then results in the wrong reading on the fuel gauge on the dashboard). To correctly determine which is at fault, remove the backseat cushion (not the backseat back support). It's easy. There are 2 bolts (10-mm) in the 90-degree of the seat (you can feel each with with your fingers when you place your hand/fingers between the seat back and the seat cushion about 6-inches on either side of the HUMP). Remove both those bolts, fold the rear seat forward, and then the fuel pump & fuel sending unit access panel will be revealed. Remove this panel. You'll then see the Fuel Pump connection and the Fuel Sending Unit connection. If you disconnect the Fuel Sending Unit connector and use a Jumper Lead to connect the Black Wire Terminal and the Yellow/Black Wire Terminal, Turn the Ignition ON, and the Fuel Tank guage on the dashboard should read FULL. If it does not, then the problem is your Fuel Gauge in your dashboard. If it does move to the Full Position on the Fuel Gauge, then the problem is with your Fuel Level Sending Unit inside your Fuel Tank.

As I mentioned above, the "float" that is part of the Fuel Level Sending Unit is made of plastic that starts to fill with gasoline slowly (anytime after 10yrs old for Civics made in the late 1990's). For Civics with this problem, when you fill up the tank with gasoline - the Fuel Level Gauge on the Dashboard will show an amount less than FULL on the Dashboard Gauge.

The good news: With the backseat off, the under-seat cover plate off, and the sending unit connection right there in front of you - you only need to unbolt it, carefully remove it (avoid dripping any gasoline inside the car, or it will take a long time to get THAT smell out of your car), then drop the new one in and put everything back together.

The bad news: This part will cost you about $115 (2012 prices, but I did find mine, OEM, with a 1-yr gaurantee for $89), and it will likely take a few days to get one delivered to your local Auto Parts Store from their Warehouse (if you go to your Honda Dealer to get one, the same part will likely cost you about 3-TIMES as much and it will still take them some time to get it delivered to their shop for you to pick up). Anyway, I have done this repair on my 1998 Civic. It wasn't too hard. Hondas, in general, are well made/designed and very easy to work on. Also, the week before I did this repair - I replaced my headlights. The Civics of this era, late 90's, also have a tendency to have the headlight housings YELLOW and have a dull image/view as you drive at night (the plastic making up the headlight assembly just wears out with time and weather, so the plastic making up the headlight fractures into TINY little cracks deep inside the plastic and the light from inside cannot make it out clearly) - anyway, I replaced those too and even put some new bulbs in. She Looks PURDY NOW!! Good Luck.