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Fuel pump?

Since April, I have had my car in four times for a problem that has never been fixed. When I go to a gas station, after pumping only 3 gallons of gas in, the pump gets kicked out as if it were full. I have been tracking the mileage, and I know when my car is near empty. The fuel gauge is also broke. They replaced the fuel pump but this did not help Can someone help me.

It’s not the fuel pump causing the click off at the pump. This would be due to a problem with the vapor recovery system, part of the evaporative emissions system. If they told you it was the pump, they are not doing the right diagnosis but throwing parts at a problem at your wallet’s expense. If they did the pump, but did not fix the gauge, or the gauge broke soon after, they did not do a good job replacing the pump. Find a new mechanic.

Your evaporative emission system is defective. There is a vent at the top of the gas tank to let air out as you pump gas in. It’s connected to a charcoal canister that traps gas vapors so they don’t go into the atmosphere. The canister is connected to the engine, which sucks out the gas vapors and burns them. Somewhere there is a defective valve or a plugged line or connection, which is preventing the gas tank from venting normally. All the air is trying to rush out past the gas nozzle, which trips the nozzle shut-off. Your check engine light might be on. If your mechanic has not checked the evaporative emission system, you need to take it to a new mechanic.

If you were in the habit of topping off the tank when you fill it up, that could be the cause of the problem. Likely if you check your owner’s manual and the informational stickers on your car, you will find at least one that warns you not to top off the tank. (Note is one cause of the vapor recovery system the others have noted.)

One not uncommon cause is the anti spill valve. If you look into the filler, you my see a steel ball. If you see it likely that is the problem and all you need to is to dislodge it. It is intended to keep fuel from spilling in the event of an accident.

Other than that has been covered by Busted and StrongDreams.

How can I get a schematic of the EVAP system to trouble shoot it? Can my husband do it without removing the gas tanks? Can we disconnect the EVAP system and put on some sort of a check valve?

We are already $900 into this issue and two mechanics (one being the Chrysler dealer).

I can’t help you with schematics, but if you disconnect the system, your check engine light will come on permanently, which could prevent you from detecting other serious problems down the road, and you will fail your emissions testing, if your state requires it. You may be able to fill the tank by putting the nozzle on the lowest notch so it fills slower, or fill it slower manually, to allow more time for air to escape the tank.

Going back a step…did your fuel gauge work before the fuel pump was replaced, and did you have any other problems that might have been related to the fuel pump and separate from the filling problem? Why did you go to the shop for the first time in April?

The reason I ask is that if you had other fuel issues, you might have needed a fuel pump anyway. If the only fuel issue was the filling problem, then I would take the car to another dealership, or another outlet of the same chain if you used a chain, and describe the problem. Ask if it could be the fuel pump or the evaporative emissions system. If they chuckle at the fuel pump idea, then tell them that another shop in their chain, or another dealership, replaced the fuel pump, and try to shame them into fixing it right for you for no additional charge. Or at least get them to call the manager of the other store and have that store make it right. For the dealship, get the zone rep involved.

In some cars, the fuel level sending unit (that communicates to the gauge) is part of the pump and you have to replace them together. If your fuel gauge worked correctly before the fuel pump was installed and is broken now, definitely go back to the shop that did it and insist that they correct their mistake.

If only your fuel gauge was broken before, you may indeed have needed a new fuel pump, but they did the job wrong or installed a bad one and they need to do it again for free.

Initially, I ran out of gas on the highway. The needle was reading full than suddenly dropped to “E”. Before this happened, I was also having the fill issue. So I thought I really ran out of gas.

Thant night we put 5 gallons in with a gas can and then put additional 5 or so gallons in at the pump (still kicking out). When I took it to the dealer they claimed that there the tank was 75% full. Note that we drove about 80 miles on that tank before pulling into to dealership. The said it was a bad sending unit.

My husband asked the mechanic if there was an issue transferring gas from one side to the other during operation and the mechanic told him that transfer mechanism was a venturi pump which wouldn’t cause the issue.

It sounds like you did need your fuel pump replaced, assuming you have one of the cars where the sending unit is built in to the fuel pump. If the fuel gauge still doesn’t work right, then the new fuel pump(s) have been installed wrong or were defective. I would think this would be covered by the warranty wherever you had it done. (90 days is usually a minimum, some places give 6 months or a year.)

However, you could also have a defective fuel gauge or a bad wire somewhere between the fuel pump and the dashboard. The sending unit sends a voltage that varies with the fuel level. I would want a mechanic to disconnect the wire from the sending unit and connect it to a transformer that can send different voltages down the wire, to see if the gauge moves properly. You would have to get the specs for the sending unit (it might be something like 5 volts for empty, 9.5 volts for half, and 12 volts for full, for example). If the correct voltage does not make the gauge move, then the gauge is bad or the wire is broken or there is a bad ground.

If you want to get the gauge fixed, I would go back to the last place the changed the fuel pump and have them fix it. If the fuel pump is wrong they should do it for free. If the gauge or wire is bad they should at least give you a break on the price for having misdiagnosed the problem and sold you a fuel pump you didn’t need.

The filling problem is separate and was not caused by the fuel pump or the sending unit. I don’t know whether you have a right to expect that it would be fixed by now because I don’t know what you told the mechanics and what you paid for. If you are in the habit of filling your tank to the very tippy-top, you could have gotten liquid gas in the charcoal canister and plugged it, this is common, and I’m pretty sure the canister is easy to replace. Your husband might be able to do it, I would start by seeing if the library has the detailed service manuals for your car. He could buy one at an auto parts store and then look under the hood and under the car to find its match, if he doesn’t feel confident he can return the part. If changing the canister does not help, there could be a pinched or damaged hose or damaged valve and that would probably take at least an experienced shade tree mechanic with the service manuals to figure out.

If you do take it to a mechanic, tell him your story (before paying any money), and ask if the filling problem is related to the fuel pump. If he doesn’t say something like, “it’s probably your EVAP system,” then go to the next mechanic. Good luck.

thank you for your advise

i took my 88 gmc truck to a mechanic, my truck was stalling and wouldn’t start for awhile till it cooled. they kept our truck for 2 1/2 months with us constantly going to check on it. we kept getting the run around.kept telling us it was ready we would take it and 1st we noticed that the gas hand didnt work and it did before we took it. we took it back. month later got it again and then it was stalling on us. we broke down 3 times after picking it up.they kept saying it was the filter, then the pump, the the top of the unit,then that the wires were all burnt and needed replaced. I was skeptical of all this but my husband has know the guys at this shop all his life and trusted them. i started doing my own research. The last time we got it back we broke down and had to walk 10 pm raining. I called the mechanic at his hm. he was rude and told me to never call again and that i didnt owe him a penny. as of now we have replaced the whole unit. i told my husband to buy a oxygen sensor because his check engine ;light had been coming on. now i think it may have just been the $20.00 sensor the entir time and the shop knew this and kept our truck on purpose because they knew we used our truck to make our living. I have reported them to bbb and am still waiting a reply. Dont ever be a victim of someone who has money and thinks it can get them anywhere.I will never take my car to another mechanic again if i can do research and fix it my self. Joe’s standard station did this to us.