Hi,

Wanted to see if this sounds right or any advice.
2003 4Runner sport V8- 91K miles

Recently had problems at the gas pump. Could only fill tank half way. Keeps cutting off and any gas station.

Shop said they check a few thing and think it is the fuel pump. Replacement cost 1400.00

Any advice
Thanks

Usually this problem is something related to the evap system. Theres a black charcoal canister on top of where the spare tire is, and it ifs really dirty/caked, then it won't vent properly. Also if you regularly top off your tank, this canister can get full of fuel and not work properly

Fuel pump is a possibility as is the fuel tank... but very rarely on 4Runners in my experience.

Usually it is an issue with the EVAP system such as vent valve, EVAP canister, and/or restricted lines.

Sounds like the tank is purging air back up the fuel filler tube rather than the vent tube causing the gas pump to think its full. Your fuel pump has no control over it. Dont bother to teplace the pump. Check the fuel filler tube and make sure its not rusty and clogged.

@Drcoffee is right, in the specific case of a 4Runner, there isn't any way that I could see the fuel pump unit (I'm talking about the whole plastic carrier that houses the sub-harness, fuel level float, the pump itself, etc.) to be the issue. On Corollas and other models there is a vapor line that goes through the fuel pump unit and we have had to replace them under a TSB or advisement from TAS for oddball refueling issues before; so I apologize for not clarifying that in my earlier post (was just generalizing causes in terms of likelihood for that concern).

That being said, that does still leave the Fuel Filler Neck, the Vent Line (including the filter), the Vent Solenoid, EVAP Canister, and the Fuel Tank Itself in order of likelihood.

Since you have an '03, the EVAP Canister is a "dumb" unit in terms of lacking the built in vacuum pump and self-checking systems the ones Toyota started using after about '05 do.

If you have an air compressor hand and you're not afraid of getting a little dirty, I'd try to locate the Vent Line that comes off the VSV for CCV (Vapor Switching Valve for Charcoal Canister Vent) and carefully unclip it from the canister and take the fuel filler cap off. The lines can be a bit stubborn and fragile so just take your time, maybe spray some washer fluid or water in a squirt bottle if it's caked in dirt. When you have the line off of the canister you can try puffing some compressed air into the line from the canister end so it pushes crud out through the open filler neck. It's not a guaranteed fix, but sometimes it can work; if the line seems to be really restricted or clogged you can try replacing the Fresh Air Filter (Part#77706-35010 should be the filter with the two lines). I have seen those fresh air filters get full of dust and debris and cause DTCs, EVAP issues, and refueling issues.

Here's the EVAP system components and routing from the FSM to give you an idea where and how it's routed:


If the fresh air line/filter seems to be clear and you get good airflow out of the filler neck I'd look at the vapor line from the canister to the tank (that should be fine as you're not getting any DTCs, but might as well look at it while you're there) and then also check the second vent/bypass line (smaller vapor line) that comes off the fuel tank and goes to the fuel filler neck. If all your lines are good, blow clear/not restricted, then you'll want to test the VSV for CCV to see that it is working. We can help you with that if you want, but if you're not comfortable doing electrical testing and/or don't have the equipment you can get a shop to test it for you.

Here's the EVAP system routing and location information to help you out.

Attached Images

PARLOC.pdf (148.5 KB, 416 views)

could also be the fuel gauge sensor giving you a false reading. i was having the same issue thinking i wasn't able to fill up. When in fact i already had almost half a tank still in there and it read less than a 1/4.

fill halfway for now. could be the charcoal canister needs to evaporate first and dry out before it can accept more fumes. always fill out until it's close to empty. let's see what happens in the next fill up. can you provide a history of your refueling habits?

yea.. I don't know if I can get behind that statement/advice.. for one, your evap canister is always working, not just during fill-ups. Secondly, I don't see how increasing or reducing your frequency to the pump is going to resolve this issue. I've personally seen multiple reasons not to run your tank near empty when possible, including elevated pump temps and clogged fuelpump sock filter from the stirred up sediment that sometimes resides at the bottom of tank.

I may be wrong with my assumption, and haven't verified this on my the T4R, but I am in the middle or upgrading my fuel system on a 95 supra, and have just gone through the fuel line modifications and had 2 mechanisms for venting the tank, one was the evap system that fed out to the charcoal canister (ie: this vent line was open to the atmosphere, hence the need for the filter) and the second was a filler neck vent, which looks to be specifically in place to allow for displacing air during fill-ups, this vent line is located behind the gas-cap so its blocked off from the atmosphere one the cap is closed.

It was my understanding that the Evap system w/canister was in place to allow for the expansion/contraction of the fuel gases with the system closed, while the filler neck vent was in place specifically for the fill-up purpose.

Regardless, I agree that I fail to see any possible way that the fuel pump could be the reason.. sounds like a good way to throw some money at a problem the shop doesn't care to diagnose... or worst yet, they know its something simple like a clogged vent line, and since they have to get dirty anyway they'll try and get you to splurge on the pump while they're at it and have you thinking that they fixed the issue via replaced pump lol.

Alot of 4runners in California have this issue because the gas stations gas pump vapor recovery system. Have to get the gas pump nozzle in just right or it will keep clicking off.

Mine does this on occasion. I find it's worse when it's hot out and I drive until the tanks pretty much empty. If I fill up at 1/4 tank it doesn't do it.