gas tank issues - Maintenance and Repair Forum

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gas tank issues
Thursday, November 17, 2016 6:49 AM

On a trip 600 miles from home.....have never had this happen before, and didn't need any new problems on top of the ones I already have and know about.

My gas gauge stopped working about 6 months ago so I have just been filling up every 250 miles or so with no problems - have more or less figured out a routine to make it work stopped to fill up on the road and only got 4 gallons in (when it should have needed at least 12 based on the miles I had driven). Annoyed, figured it was just that particular station but the same thing has now happened in 3 different places hundreds of miles apart - 4 gallons, 3 gallons, 5 gallons, etc..... and the pumps keep shutting off and I can't fill it up. Obviously with a not-working gas gauge, this is a big problem. if that wasn't enough, - and I have to think this is related - I notice a new (never heard before in 16 years with this car, EVER) - buzzing/humming fan-running type noise/sound coming from the rear of the car and the only thing back there is the gas tank. So now I am thinking the fuel pump is on the way out in the middle of a 1000-mile-long trip.

Anyone have any experience with either of these type of situations? And if so - are there any solutions? I am totally broke and have been sleeping in the car on this trip so any work will have to be done myself and of course dropping the tank is going to be a lot harder if it is full of gas and since I can't know how much gas is in there given my current situation, I am a little worried to say the least.

Re: gas tank issues
Friday, November 25, 2016 2:42 PM

So made it - with the engine acting like there is a fuel line problem - all the way to my destination but now that I am 800 miles from home, the car seems to be a lot worse.
Forget the tank filling capacity issue for the moment. The fuel pump buzzing / humming and the rough / sputtering engine are a lot more of a concern and worry right now.

I am hoping that the fuel pump is not dying. What I am hoping - and asking anyone who knows - is could this noise from a struggling/sick pump be caused by having picked up
some crap in cheap gas (and believe me, I filled up at a REAL dump of a tiny middle-of-nowhere station that I have never been to before on the way here, I am desperately hoping that I can make it to the nearest autozone or advance and pick up a $20 fuel filter and that replacing that will be all the pump needs to shut up and go back to normal operations.

So I'd have to do the filter replacement in my dad's driveway. I put this project off for a long time and it needs to be done regardless of the pump issue. Is there anything I should know about the green quick release tab from hell that I haven't already seen, watched or read online in the last hour? I cant afford to get the thing off then not get the new one on.

Any advice on whether a clogged fuel filter could make my fuel pump buzz loudly - and / or any advice on the filter replacement would be appreciated.

Sunday, November 27, 2016 1:07 PM

Not that anyone cares, but thought I'd provide an update. From bad to worse. Went out to head to the parts store for a fuel filter, car won't start. Not getting the pump noise when turning key to ON position as I have for 15 years. Cranks but no start. Crawled under car, pounded on bottom of gas tank a few times - then the normal sound when turning key to ON position but didn't want to start car with no confidence I would get anywhere without getting stuck on the side of the road on the way there.

What does the fact that pounding on the bottom of the gas tank tell me? Is the problem with the pump 100% electrical failure in nature or could something be mechanically blocking the pump from operating? Also - another puzzling thing to me is that this new abnormal loud buzzing or humming from the gas tank (pump) only happens once the engine had started and the car was running - not in those 2 seconds when the key is just in the ON position. Sounds like it always does at that time.

I can't afford to pay a repair shop to fix it anyway so for now the car is stuck and I am stranded at my Dad's house until I can figure out what to do.

Anyone with experience or advice, feel free to let me know your thoughts.
Re: update
Sunday, November 27, 2016 6:45 PM
If you bang on the tank and the pump starts working it is probably a bad commutator which when it stops at that spot it will not turn without vibration to move it a tiny bit. 99% sure from that information you have a bad pump and it is recommended to replace the pump and filter together. You will have to spray the fuel filter with penetrating oil for a while if it is rusty. If it does not come free you may have to heat it with a torch. If you smell gas or have leaks do not do this. Do this at your own risk in a ventilated area. Once it is hot and you can break it loose then let it cool before separating so the gas does not ignite, here is PA I have to do this a lot and I have to get the line very hot, if you do this do not take any lines off until you break it loose, if it does not come loose then leave it.

On the inside my car looks like a fighter jet.
Re: update
Monday, November 28, 2016 1:33 PM

Thanks for your reply. That makes sense. One thing that I just cannot seem to find a definite answer on - and this is after days of reading every website you can think of about this problem - is whether or not on my model car (2001 cavalier) the OIL PRESSURE sensor/switch has anything to do with the fuel pump running after the engine is started. There seems to be a fierce discussion and arguments / disagreements over whether the fuel pump is always, 100% of the time - both when turning the key to the ON position to prime the pump and also during normal driving conditions - getting power through the RELAY - OR whether once started, the oil pressure sensor takes over and that relay is out of the mix and irrelevant.

Can someone answer this once and for all? If my car was working / starting / running right now, I would go out and let it run for a while and then pull the relay to find out what happens.

Thanks again.
Re: update
Monday, November 28, 2016 1:41 PM
The fuel pump primes and turns on through the relay only under normal operation. The oil pressure sensor will supply the fuel pump with power if the fuel pump relay fails while driving with zero interruption. If the relay fails and the car turns off you will have to crank the engine till oil pressure build and the oil pressure sensor will power the fuel pump. You will know this by having very long crank times to start the engine.

On the inside my car looks like a fighter jet.
replacing fuel pump
Wednesday, November 30, 2016 12:45 PM

I have two major concerns when trying to decide if I should replace the pump myself. The first is - the tank should have over 10 gallons of gas in there. So would I have to siphon most of it out to make the tank a reasonable weight? Otherwise I am afraid the thing is going to be so heavy it will be impossible to handle or push back up.....not to mention getting gas everywhere. The second is the fear that the connections won't match exactly. Of the video's I've watched, that one thing makes it look like the difference between a reasonably easy job and a nightmare. Especially since I have to figure out how I am going to get to the parts store just for the pump. Once I am back and have everything jacked-up and completely apart, I would be extremely screwed to find out the plugs/wires/connectors are different and some kind of crazy cutting, splicing, twisting, soldering disaster would be required.

Has anyone done this job and did the connections on the new pump match the ones on the original?
Re: replacing fuel pump
Thursday, December 01, 2016 7:14 AM

I got the car stared one time yesterday. Once started, it ran fine and never stalled. I removed the relay and fuse for the pump and swapped the relay with the identical one next to it for the AC and examined the 15 amp fuse but everything looked fine. The only odd thing was that the fuel pump relay was really dark and discolored compared to the AC and it was also hot after the car had sat and run for 15 mins. But then after I turned everything off I couldn't get the car started again and again had total silence from the pump under all conditions - no "ON key position hum" and no ability to restart the car despite repeated pounding on the bottom of the tank.

I have read that there is some kind of direct wire test lead that goes straight to the pump somewhere around the driver's side wheel well or shock tower, but I don't remember ever seeing anything like that under there. Is this true and if so, would it serve as a last-resort indicator that the pump either works or doesn't work (and rule out any other problem) if you were to connect a jumper to the positive battery post? I hate being stranded and am now at the point where my choices seem to be having the car towed some place or trying one of those mobile mechanic guys which I have never done before. If I do either one of those, I sure as heck want to make sure that replacing the pump will 100% for sure fix the car's starting and running problem.
Re: replacing fuel pump
Thursday, December 01, 2016 8:01 AM
I do not believe there is a test wire on a 3rd gen, That is only first and second gen cars. I could be wrong but I never saw one.

On the inside my car looks like a fighter jet.
Re: replacing fuel pump
Friday, December 02, 2016 12:20 PM

The sending unit is part of the pump, right? So at least a new pump will fix the broken gas gauge problem? Someone told me that the pump and sending unit are two different things and not related but from what I can tell they are all part of the same assembly / kit. It would be crazy to replace the sender without putting a new pump in there unless the pump was pretty new, right? OR am I on drugs?
Re: replacing fuel pump
Friday, December 02, 2016 3:18 PM
On 2000-05 they are usually sold as one piece. You can order just a pump or the gauge sensor and save money if you want to do it yourself. I would not buy a cheap pump, they have been known to be made wrong with the float on the wrong side or other annoying issues. I will only buy AC Delco ones after the issues I have had.

On the inside my car looks like a fighter jet.

fuel filter backwards
Thursday, December 08, 2016 4:46 AM

So I got tired of dealing with it and just took it to a place for the work. These guys must be total idiots. When I got the car back it ran and is continuing to run rougher than it was on the way there with the failing/dying pump. Then I get home and see that the whole back seat had been ripped up and there is crap all around the back so my assumption is that this guy thought he could get to the pump from the back seat.

Then - after being alarmed at seeing that, I crawled under the rear of the car to see the new filter - on in the opposite direction from the original one with the steel nut and green clip on the opposite side as they were before I brought it to this place.

So my whole new set of questions is about this fuel filter direction and 1. - if it matters and 2. - if it could be causing the rough engine performance.

I just cannot win.
Re: fuel filter backwards
Thursday, December 08, 2016 7:49 AM

After thinking about it and crawling under there again, I don't see any way that you could install the filter backwards. So I'll toss that out, but I started the car up and there is absolutely no change or improvement in the difficult starting, and rough engine from before the new pump and filter were installed - and they verified that the pump was the problem.

So.....assuming the problem is fuel-related and also related to whatever killed the pump - which I still think was a really bad tank full of @!#$ty gas from this SC station on the way down here - then what else is left that could be suffering from that besides the injectors? I just sank $600 into the problem yesterday and am unhappy to have not improved the situation with a new pump and filter. Should I try driving around for a few weeks to see if things slowly improve as I burn through the gas in the tank now and fill up with better (normal) gas? Should I wait until I've driven back the 800 miles on the interstate at 80mph to clean things out and then see how it is? Should I go pour a bottle of fuel system cleaning stuff into the tank? Or do you think it is unrelated to the fuel system?

Puzzled, worried and unhappy and poorer.
Re: fuel filter backwards
Saturday, January 28, 2017 9:29 PM
I'm not sure if you fixed this, but I could definitely run some seafoam through the tank to at least clean the injectors in the engine. I'd put 1 can in when there's about 1/4 - 1/2 tank. Does your gas gauge work now after the new pump. That would at least be a positive

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