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1G Gas station pump keeps stopping

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AWD-Tony

Proven Member
6,801
3,735
Sep 11, 2017
Cincinnati, Ohio
I’ve never had an issue filling up with fuel. I recently replaced the rusty filler neck and both hoses. Went to fill up and the pump kept stopping after a few seconds. I understand the pump stops using Venturi effect so I’m not sure what’s going on. Could the angle of the rubber 90* elbow be causing it to back up?

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https://www.dsmtuners.com/threads/1g-awd-smaller-filler-neck-hose.531814/
 
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Was the original hose a 90* or was it maybe a little less so it wouldn't pool at the bottom where it bends at? I haven't had any problems with mine and I used a part of a radiator hose in that spot, but.....its been along time since I've been to "the pump" to be honest.
My DD Saturn does that to me too and IDK why so I have to just fill slow.
 
I believe the breather/filter on top of the tank can go bad/clog and cause pressure to build in the tank. When that happens it may be too much pressure to pump. Sometimes this causes leaks when pumping gas. Maybe unhook that breather to let the tank breath and check.
 
Was the original hose a 90* or was it maybe a little less so it wouldn't pool at the bottom where it bends at? I haven't had any problems with mine and I used a part of a radiator hose in that spot, but.....its been along time since I've been to "the pump" to be honest.
My DD Saturn does that to me too and IDK why so I have to just fill slow.

That’s the only thing I can think of that’s causing it. When it runs low, I’ll take some off the top of the 90* hose to see if that helps. Original was close to a 90. Threw it away so don’t know for sure. There’s a pic of it on the other thread.


I believe the breather/filter on top of the tank can go bad/clog and cause pressure to build in the tank. When that happens it may be too much pressure to pump. Sometimes this causes leaks when pumping gas. Maybe unhook that breather to let the tank breath and check.

Is it that blue thing? Don’t think it’s that since it started after I replace the neck but I can check.

@1990TSIAWDTALON it looks like a 90

@Vegas Smith just open the cap and it didn’t release any pressure so I don’t think that’s it

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Hmm. I hope someone that has experienced this first hand can jump in. :hmm:
 
Only thing I can think of is that the smaller metal vent pipe that joins the main one up by the fill end has a blockage on it. You could disconnect the small hose and try to fish something up there, or see if you can bow air through it. Of course if there is crude in the way, you might dislodge it down into the fuel tank. Perhaps drive it until almost empty, and remove the whole fill neck assembly to diagnose. If it wasn’t doing this before, what’s changed. I can’t see the rubber hoses causing this.
 
I blew out the filler neck with water and air before installing it since it was sitting around for a while. I also cut the smaller line so there shouldn’t be anything in the (tank side). I’ll double check when I pull it off. It’s got a full tank now and the weather is crap here for the next week so it’ll be a while before I update.

Thanks for the input fellas!!

@jk’s97dsm can you upload the fuel tank diagram when you get a chance? I want to know where that smaller line goes to. Thanks
 
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@jk’s97dsm can you upload the fuel tank diagram when you get a chance? I want to know where that smaller line goes to. Thanks

The small line goes up to the vapor canister in the engine bay. It is a steel line that looks identical to the fuel return/supply line.

As I said, mine was capped until recently at the top of the tank and I didn't have this issue. My only fuel tank vent was the cap.
 
The small line goes up to the vapor canister in the engine bay. It is a steel line that looks identical to the fuel return/supply line.

As I said, mine was capped until recently at the top of the tank and I didn't have this issue. My only fuel tank vent was the cap.

Thanks Ben. Yeah I still have that line and I’ve never messed with it.
 
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I’ll have to check the overflow check valve. I’m glad it’s easily accessible.
Thanks man!! I appreciate it.
 
My understanding is there is a vent line and a vapor line. The vent allows gallons per minute of liquid fuel to flow into the tank with the displaced air and vapors to flow up to the filler neck and exhaust to the atmosphere ( unless your station has one of those snorkels that captures them). Then you put the cap on the filler neck, and as vapors build pressure, they flow through the vapor line, through the “check” valve, through the “roll-over” valve, and into the charcoal canister. I don’t think the vapor line can flow fast enough To vent the tank during fuel filling.
 
So I pulled the overflow check valve. At first it was hard to blow in either direction. I cleaned it with some brake cleaner and some crud came out and now it’s free flow the opposite direction of the arrow on the valve (green arrow). In the direction of the arrow (red), it’s harder but does open slightly at about a few psi of me blowing into it. Shouldn’t it flow freely in the direction of the arrow on the valve? And is this a one way check valve?
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My understanding is there is a vent line and a vapor line. The vent allows gallons per minute of liquid fuel to flow into the tank with the displaced air and vapors to flow up to the filler neck and exhaust to the atmosphere ( unless your station has one of those snorkels that captures them). Then you put the cap on the filler neck, and as vapors build pressure, they flow through the vapor line, through the “check” valve, through the “roll-over” valve, and into the charcoal canister. I don’t think the vapor line can flow fast enough To vent the tank during fuel filling.

Not sure why I didn’t get this notification. So the overflow check valve has nothing to do with my problem and it has to be something with that vent tube on the filler neck.
 
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Well, I’m not offering that kind of conclusion for the problem with your car, but I don’t think it would be related to the small vapor line that comes from the very top of the tank. The whole reason that there is the much larger vent line is to vent during filling. The part you replaced was the filler pipe, which has the junction between the vent pipe and the filler neck. When you replaced this part, a new problem with tank venting started. I would start by looking for a blockage somewhere in there. If you use a piece of hose connected to that section of vent line, you should be able to blow air by mouth with little effort, and plenty of flow. If that works, then try blowing into the rest of the vent line (into the empty tank). If both work fine, then more head scratching is required. That’s my suggestion.
 
Well, I’m not offering that kind of conclusion for the problem with your car, but I don’t think it would be related to the small vapor line that comes from the very top of the tank. The whole reason that there is the much larger vent line is to vent during filling. The part you replaced was the filler pipe, which has the junction between the vent pipe and the filler neck. When you replaced this part, a new problem with tank venting started. I would start by looking for a blockage somewhere in there. If you use a piece of hose connected to that section of vent line, you should be able to blow air by mouth with little effort, and plenty of flow. If that works, then try blowing into the rest of the vent line (into the empty tank). If both work fine, then more head scratching is required. That’s my suggestion.

Yeah it’s definitely a head scratcher. The piece of new hose was pretty tight so I think I’ll have to remove the filler neck completely to check. Thanks man!
 
Might be a dumb question, but is the filler hose "clocked" correctly? The tabs towards the bottom look like they are different in the pic. Thinking maybe if the angle is off, it causes the fuel to slosh back and trip the pump?
 
Might be a dumb question, but is the filler hose "clocked" correctly? The tabs towards the bottom look like they are different in the pic. Thinking maybe if the angle is off, it causes the fuel to slosh back and trip the pump?

It only fits one way. You’d have a ridiculous hose to the tank if it was clocked differently
 
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