1998 xc70 1/98 build Problem filling gas tank (meta discussion on evap config) Topic is solved

[Brickbox8398]

Hey everyone. I have a 98 V70XC that i've been driving for about a year now. Going into this, my first AWD P80 and knowing this car was neglected when I got it, I knew I'd have fuel related issues at some point because of the complicated fuel system, and it finally happened. Currently I cannot fill the gas tank unless I am holding the pump trigger as little as possible. It takes almost 10 minutes to fill the tank. So far I have had no success filling the tank at normal speed with the following conditions:
-Rollover valve disconnected
-Rollover valve removed and splicing the two lines
-Disconnected all three lines going to my canister (purge, tank, and vent/shut off valve)
-Disconnected the line which goes to the top of the filler neck. This connection is accessible from the trunk access holes. I believe this one follows the top of the tank and connects to the top driver side of tank. From my research this is the "overflow" line? Being on the top of the tank and going to the top of the filler neck, it is likely this is what actually turns off the pump when the tank is full.

I have done intense research on this topic but I am lost for ideas. When I fill the tank and the pump clicks, I can hear gurgling in the filler neck. I don't know why fuel cannot flow especially with almost everything disconnected that could cause a problem. With all of the above things disconnected at the canister it rules out a canister issue. With the tank top driver side hose disconnected the tank should be free to vent, but it doesn't. When I do have the patience to fill the tank, my garage reaks of gas and makes the whole house stink. (Note this is with all of the above things connected, and no CEL for EVAP leak). On top of that with the classic issue of a fuel gage that doesn't work this car is becoming impossible to daily drive.

[Cees Klumper]

Have you checked the main filler tube/hose for restrictions? This happened to me on a different make car and it was the filler hose that was kinked and would not allow fuel to flow more than a trickle.

[jimmy57]

There is a vent hose, around 1/2 inch diameter, that goes up and has a bend and has a round filter on end. If that has gotten a mud dawber nest, spider nest, etc. in it so that it doesn't flow freely, the vapors can't escape as fuel goes in and the vapor and fuel spit back and trigger fuel nozzle shut off. The vapor goes through charcoal vapor canister above rear diff to the right and then through a canister vent close valve and then through that hose. If the canister vent valve sticks or the charcoal canister or any of the piping gets blocked, filling fuel will have problems with nozzle tripping off. It does this every time? I ask because 98s have an issue where fueling after a 30+ minute drive can give this issue because the system is doing a fuel tank vapor loss test and turning off ignition doesn't immediately kill the engine computer power supply and it will keep the canister vent valve applied (closed) for 4 minutes. Turning ignition on and off fixes this.

[Brickbox8398]

There is a vent hose, around 1/2 inch diameter, that goes up and has a bend and has a round filter on end. If that has gotten a mud dawber nest, spider nest, etc. in it so that it doesn't flow freely, the vapors can't escape as fuel goes in and the vapor and fuel spit back and trigger fuel nozzle shut off. The vapor goes through charcoal vapor canister above rear diff to the right and then through a canister vent close valve and then through that hose. If the canister vent valve sticks or the charcoal canister or any of the piping gets blocked, filling fuel will have problems with nozzle tripping off. It does this every time? I ask because 98s have an issue where fueling after a 30+ minute drive can give this issue because the system is doing a fuel tank vapor loss test and turning off ignition doesn't immediately kill the engine computer power supply and it will keep the canister vent valve applied (closed) for 4 minutes. Turning ignition on and off fixes this.

The 98s are different or at least mine is. Charcoal canister is up at the front drivers fender. Again I should have ruled out issues with the canister when I disconnected everything before fillup to see if it helped which it didnt. This 1/2" vent hose you're talking about is what I mentioned in my original post connects the driver side rear of the tank top to the top of the filler neck. The difference with my car is there is NO air filter in this circuit as you mentioned. Just a funny expansion chamber thing, not sure whats inside that but its unservicable. I've seen the older posts talking about it too, possibly being clogged by mud dawbers. When I dug into the filler neck this is what i was hoping to find but of course it turned out not a possibilty on my car. The issue with filling up is every single time. It was not a problem for the first 8 months I drove this car though.

[Brickbox8398]

Now that i'm thinking back to when this began, it was shortly after I had replaced the pressure line going from the fuel filter to the sender. My car is in rough shape so dropping the subframe to get to the fuel lines running above the tank was not an option, it would total the car (it is held together by rust, lol). Long story short I had to forcefully remove this fuel line sandwiched between the frame and gas tank on the passenger side in order to salvage the ends with the fittings. I just looked under the car and the hard plastic line that goes up to my charcoal canister labeled “tank”, follows the pressure and return line to gas tank and then disappears above the tank back to the access hole area in the trunk. I disturbed the pressure line aggressively, so I wonder if I pinched that plastic "tank" line somewhere that I can’t see. I might try splicing in a new section with rubber hose to test this theory. See pictures below which might help explain things.

[abscate]

I have never heard of an xc70 with the charcoal canister up front. Look from the rear of the car underneath amd confirm you don’t see the canister back there.

[Brickbox8398]

I have never heard of an xc70 with the charcoal canister up front. Look from the rear of the car underneath amd confirm you don’t see the canister back there.

It’s real. And it is very easy to access the connections by removing the driver side blinker. If I need to remove it it’s one bolt and it drops down. This picture is looking in through the blinker

[abscate]

Wow. That’s truly a bizarre hybrid setup. I looked on online Volvo parts and found no corresponding diagram.

That looks like the late model rectangular carbon canister mounted in the earlier driver fender location.

Jimmy57is probably your only hope as to how that it plumbed.

There are pictures and diagram on the Ekaterina resurrection thread but those are all the later rear canister models from 99 on

[Brickbox8398]

I have used those pictures to help locate the various lines on my car which have sprung leaks. Because many of my repairs have been done via untraditional methods… I have been repairing my fuel system by abandoning the old lines and cutting holes in the floor to splice into whatever good sections were left. I took the fuel pump access mod to a whole new level, haha.

I will update this thread when I have time to dig into the fillup issue again. I hope it will be helpful for someone else in my situation. I love these cars but they are showing their age and require some crafty repairs to keep them going

[abscate]

I did stumble on another thread of someone with a 1998 R which also had evap canister up front and AWD of course.

Are you sure you cant get that back axle down? It is a pain the first time, after that, with new hardware, its not bad at all.

My fuel lines on top were a rusted mess of crap which all had to be replaced - for certain if I had left any piece in it was days from leaking again. NiCopp is cheap - and you can put all the fittings in accessible places, too.