Takes a verrry long time to pump gas
 

I searched and couldn't find anything relevant

When I pump gas it takes super long for me to fill up. I have to go slow or it overflows, and I can't get the handle to stay down, I have to manually hold it down at like 1/3 of the way in.

it sucks because I premix and need to fill up all at once. seriously takes me 20 minutes for 15 gallons.

something wrong with my fuel filler neck?

How long have you had the car and has it always done this?

Ive had it like 5 years and its always done this.

used to not bother me cuz i rarely get gas.. but im starting to drive it now and it sux

edit: at least i think it has been always like this

Hi................. try removing the vent(line)BIG ONE on the carbon canister under the hood on the right side of the car you might have a plugged canister ,or your tank vent is plugged, or maybe twisted or has a kinked hose If you remove the left hand lower plastic tank cover it may be able to inspect the filler neck,if not you can always drop the Tank for a peek ,,,,,,,,,,,,,good luck

Mine did that too for the longest time [not to that extent though] but the trick for mine at least was to point the nozzle towards the back of the car when pumping gas, the tank has a seperate "breather" line inside the filler neck if you will that helps allow air to flow past when the tank is being filled, as soon as I figured that out and aimed away from it, the problem went away.
http://i469.photobucket.com/albums/r...b/DSC08041.jpg

ive tried disconnecting the line on the charcoal canister and pointing it towards the back of the car when pumping gas. it seems to help a little bit but if i try to pump too fast it overflows over the outside of my car.

getting gas is so frustrating

the pump nozzles r designed to shut off to prevent fuel from overflowing back out and onto the ground. how far down into the filler neck do u put the nozzle?

Wow, I'm having the same problem. Starting about 3 months ago (every thing was fine before, set the gas pump on the highest notch and it shuts off when full, according to Michael's instructions) my otherwise Perfect Silver One started popping off the pump on the high notch. I'd have to reset at the low notch and even then I couldn't get the last three gallons in until I'd driven a bit down the road and stopped at the next station.

Eventually I realized if I nursed the last three gallons using the trigger (lowest setting on the pump doesn't work, pops off right away) I could get the full 15 gal. and not have to stop at the next station (I'm premixing too, so to get the oil/gas ratio right I need to get the 15 gal). That's what I'm doing now.

So yeah, it's a pain, glad I noticed this post.

Tim says its my fuel level sensor (I don't think so, I keep track otherwise) and Billy says someone stuffed bananas in my gas tank, which might be the case.

But I'm thinking there might be a more technical explanation.

I'm gonna' do the stuff recommended in this post and get back to ya'll.

How big is the tank on the GSL-SE? I've only ever put around 10 gallons in, anymore than that and it stops the pump. I too have to pump slowly or it will cut off. Figured it was just because it was an older car?

15 gallons probably, if SE's are the same at the GSL's (pretty sure they are).

All four of my 84/85 GSL's filled up just fine with the pump notch set on high, right up to the 14+ or so gallons needed to fill.

But now that just doesn't happen, sure wish it would.

if ur mixing for 15 gal, is it really that much of a problem if u only get 14.5 or 14.8 or 14.3 in it? so it's got alittle more oil. better than too little, right? maybe u guys should mix for 14 gal or go alittle longer before filling up.

Sounds like an easy explination I would think...??? Like when you're trying to pour something thru a funnel and it goes slow or nears the top of the funnel nearing overflow b/c the air can't escape as fast as the fluid that wants to take it's place. Lift the funnel a bit to allow air to escape and wallah... fluid entering picks up speed. I've sometimes jumped the gun with my responses and I hope this isn't one of those times but it sounds like your vent is clogged. On the picture above there's a feed line (the larger of the three) a return and a vent. I'm not sure which is return and which is vent but it sure as heck sounds like the vent line is partialy clogged not allowing air to escape which won't allow fluid to enter (or real slow in your case).

lmao! my DD 2009 jetta is like this too. if you let the pump do it, it'll put 12 gallons in, if I do it, its like 14....

however the mazda is japanese, and we expect japanese things to do work properly, because they usually do.

the fuel filler assembly is pretty simple, there is the big main fuel hose, and a smaller vent line. filling the tank with liquid, means you have to vent some air, as the tank is not empty, its just not full of fuel.

there is a flapper valve at the top that is supposed to prevent you from doing something that never happens, perhaps filling the gas tank when the car is upside down? i don't know.

what i suspect is happening is either the vent line is clogging from old age, or premix as the premix really would rather go down the vent unless you have a nozzle/funnel thing

the whole thing is very easy to check, its all assessable from under the car, and you probably wont even have to drop the tank

welcom to the club mine does it too i have it solved already FUEL CELL.
I would just deal with it, its not causeing any other problems other then you being late.

Clean out the vent line that goes up to the fill port, those damn mud wasps tend to fill them with debris.

Thanks TIIDevil, J9, FOP and Darren for the clues on the vent hoses, I check those to be sure they and the carbon canister aren't plugged. Should be able to get to it this evening, but I'll have to wait to the next fill up in a day or two to know that it worked.

While not a Mazda, my Datsun did the same thing in the past. It was a vent tube plugged, nothing major. I'd say the advice given about the vents is probably spot on. Depending on the width of the vents on this car (I'm not yet familiar with them), a clothes hanger with a soft end taped to it should suffice in cleaning the tubes.

Ray another thing I have run into was a rust filled plugged vent line in the gas tank, how we cured it was fairly simple, we ran a speedo cable into the pipe and turned it slowly and the vent opened back up( remember no sparks , or battery connected when messing with your tank),its one way of checking for open lines on your tank as well..................... good luck .................. fred

Sounds like this problem may actually be fairly common but not getting fixed because we just put up with it, finding tricks to get the gas in.

When I tanked up this afternoon I disconnected the carbon filter under the hood to see if that would fix the "vent" problem but it made no difference. I still had to put the pump on slow until it clicked off at around 10-12 gallons, then nurse in the last few gallons by delivering a trickle with the trigger.

While those last few gallons are going in there's a whole lot of gurgling coming out of the filler neck, like air isn't getting where it should when it should. So I like the vent line idea (thanks for the tips guys) but won't have a chance to take a look at that until I get some daylight tomorrow.

If I don't see anything obvious with the vent I guess I need to get out the FSM and go over the fuel system tests, make sure those check valves and things are all working right. I'll report back when I learn something.

u guys have to realize how much fuel is still in the tank when u trying to put 15 gals in it. u'll need to run it almost completely out if the tank holds 15 gals. u can't have 3 gals in it and expect to put 15 gals in it.

My old 1985 GS used to do this all the time and it drove me nuts. Most of the time it would shut the pump off somewhere between 7-11 gals, even when the tank was on E. While I do agree with you about the fuel reserve in the tank, I don't think that's the problem. Ray is right about the tank gurgling when you fill it up. It gurgles and gulps like crazy when you are spoon feeding it those last 2-3 gallons of fuel.

Ray, please let us all know if you come up with anything in your searching/wrenching. I've got another 1985 GS that I'm working on right now and I'd bet it's going to have this same issue the first time I gas it up. It's one of those things that you think about while you are gassing up, but then as soon as you're done it goes to the back of your mind and you never think to try and fix it.

This might sound like a dumb question, but have you tried filling up at other gas stations?

Wouldn't stuffing something into the vent hose possibly dislodge the debris right into your gas tank? That seems like a bad idea.

Yep I tried other stations, in fact the first couple times it happened I blamed it on the pump, even told another customer to watch out because they weren't working right. Of course all my cursing at the gas station didn't help the situation and I had to eat crow when it kept happening at the other stations. (Moral of the story: Don't believe things people tell you at gas stations).

Thanks for the tip on the residual gas Michael. Because I'm using the Silver One for my daily 110 mile commute I have the gas consumption figured very closely, usually down to the last half gallon. Basically I expect to get 340 miles+ between fill ups, with the fuel gauge bouncing on empty and the warning light pretty much steadily on. Then I expect to add 14+ gallons to the tank.

In fact, at first I was wondering if it was a fuel gauge problem and I wasn't getting an accurate reading on what was left in the tank (especially after Tim pointed out that a ground fault to the sensor could cause this) but on careful checking I established when the gauge said empty it really was empty. Using the dribble method, I've added 14.6, 14.7 and 14.2 gallons on the last three fill ups, respectively. So there really do seem to be some banana's in the filler neck or something like that.

And yep Starfox, I was thinking the same thing about reaming out the vent hose, probably not a good idea doing this from the top down with the debris ending up in the tank. So I guess I need to get under the car and work from there, hopefully some time later today.

as far as the debris is concerned the tank filter is located outside the tank before the fuel pump it will filter it out and prevent it going into the pump/engine ,unlike a 2 gen 3rd which has a pre - filter screen on the pump in the tank,if the vent is the issue and you solve it ,then the tank would have to be removed and flushed .

The vent hose should have a hose clamp on each end. It should be as easy as un-clamping the hose, pulling it off the tank and cleaning it out with something. Then after you get it cleaned out hook it back up to the tank and see what happens.

So it's a beautiful day down here in NE Georgia, about 80 degrees, bright blue skies with puffy white clouds floating by, very low humidity and a gentle breeze.

So I went out to check on this slow fill problem and discovered some interesting things.

Yes Jamie, I found those clamps, I could just get my hands on them by reaching up around the tank and sheet metal from underneath (for the lower one) and by taking out the rear interior trim and reaching down around the sheet metal for the upper one. I was even able to squeeze the hose over most of its length and it sure doesn't seem to have any major occlusions or crap in there.

But forget about getting a tool to either of those clamps to squeeze them and get the line out, the tank needs to be dropped if you want to service that hose. Of course on this beautiful day the tank happens to be full to the top, so it's not coming out this afternoon. Maybe never actually, hanging out at the gas station dribbling gas into the tank once in awhile is probably preferable to pulling and servicing the entire fuel system.

So at that point I'm thinking that 9595's idea of sticking a speedo cable down from the topside (and yes dislodging the crud into the tank or a filter or whatever is down stream) was making a lot of sense. Hey, what's a little more crap in the fuel tank if it fixes the vent problem?

However, the 84/85 Mazda engineers decided they didn't want us to do that so they placed a metal shield in front of the vent opening inside the fill tube where it comes in at the top - you can't get a piece of thin wire in there. Apparently they only did this for the 84/85 models, I have a tank from an 83 that doesn't have this "protection" (Damn It).

So I'm back to the science of troubleshooting to figure out exactly which component in the fuel system is causing the pressure to build in the tank while filling, causing my gas station visits to be longer than planned.

I checked the FSM and the Haines manuals and of course they provide all kinds of information about everything except this problem. I guess the Mazda engineers never had this particular problem, even though a bunch of us guys who drive their cars do.

Hopefully the wizened old crew here at RX7forum will provide the missing information, but in the mean time I do have what might be a clue. The problem began shortly after I discovered that the check valve in the fuel return line to the carb wasn't working, so I replaced it with one that was.

Could adding a functioning check valve to the fuel return line to the carb have revealed another problem in the system, say another malfunctioning valve somewhere that wasn't a problem when the fuel return check was letting fuel pass both ways?

I had this happen to mine and it turned out the Check and Cut Valve was installed backwards.

This happens to me too!! I also premix the seven. Does anyone use a funnel to add premix,or do u just add it right into the tank? Maybe the premix is actually running through the vent hose n causing some sort of restriction?

If I have time, I'll try n drop the tank n check the Vent hose

I think I got that check valve on the return line right. When you blow it goes, when you suck it doesn't, right?

I just pour my premix oil into the throat of the filler tube, flush it with the gas. Figure it must get down to the tank somehow, I never see any on the pavement.

I noticed something similar on mine. May shed some light on the whole situation.

Started premixing and first time added oil first (straight to the filler), and it gurgled and cutoff a bunch. Literally took 20 minutes to get 12 gallons, at which point I gave up. The second time I filled it up, I went ahead and started pumping gas, pumped perfectly fine up to 13 gallons or so, then I added the premix, started pumping gas and viola, the gurgling resumed and it wouldn't accept much gas.

Next time I'm going to try a funnel I have (somewhere :-/) that has a foot long clear hose (1/2" diameter or so) coming off the bottom. I'll thread the hose into the neck, most likely all the way into the tank, add the premix there, then pump the gas. I'm thinking that the thicker oil partially blocks that vent tube, so the air trying to come out of the tank is forced up the filler neck, causing all this trouble.

Hmmm, that does fit my situation exactly, the problem started when I started pouring the 16 oz. of premix into the filler tube. Since I haven't been using a funnel to make sure it's delivered passed the spring flap thing I suppose a good amount of the premix could be backing up and ending up in the vent tube.

But I still don't see how that would foul things up. Wouldn't the premix just drain down the vent tube back into the tank? The premix oil isn't that much more viscous than gas, I don't see how it could cause any channel meant to flow to clog up.

Similar story here in a reeeeealy old thread I happened across today. https://www.rx7club.com/1st-generation-specific-1979-1985-18/problems-pump-119085/

Again kind of pointing toward premix. If the weather cooperates this week I'll make a few commutes in the rex so I can fill her up again, using the long hose funnel for the oil this time.

Nice find Newbie, that's a perfect description of what I've been seeing since adding the premix. I think we are getting someplace - it might be how you add the premix.

In fact I tanked up today and tried something new - I used a long screw driver to open the spring loaded flap in the filler neck, then carefully poured the premix in so that at least most of it went down the filler tube.

It still had some problems but the tank was much easier to fill. I had to put the pump notch on low speed as usual, but this time it stayed on all the way till I reached 13 gallons (it was clicking off at 10-12 before, sometimes even earlier). Then I was able to top off the last gallon and a half without the usual dribble dribble dribble.

A bit early to tell but I'm going to get one of those pointy funnels before the next fill up later this week.

Thanks Newb!

OK, I think the problem is solved. Today I filled up again, but this time did a good job of getting all the premix oil delivered down the filler tube using my new high tech premix apparatus:

http://i764.photobucket.com/albums/x...7/DSCF3471.jpg

And what do you know, I put the pump setting on high and it filled the tank without a hitch, right up to 14 gallons. Then I topped off the last half gallon and the tank was full to the top. Just like old times, before I started adding the premix to the tank.

Three or four of the folks who posted on this thread with the same slow filling problem (including me) are all premixing their oil. So my guess is even a little oil down the wrong tube and the vent stops working properly, causing the problem.

Given this seems to be a common problem, it might be a good idea to archive this thread!

weird, the premix must be thicker enough to really foul things up!

explains why i didn't have this problem on my FC too, i had a funnel

fuel tank
 

We had the same problem in 1974 RX-4 wagon. Mazda had a recall. It was the hose from the filler tube to the gas tank. That solve the problem, before that is was hell after a half of tank and that was after we waited in line for 2 hrs, for gas.

Thanks Ray. I should have read this earlier today. I was getting the evil eye from this guy waiting for a pump.

It sure does make a difference. I filled up again last night using the funnel and once again, with the pump handle set to high the tank filled right up to 14.5 gallons before clicking off, right where it should.

I agree with J9 though, it's weird that a little premix oil down the wrong tube could have such a big effect. I'm just glad I didn't pull the tank and rip into the fuel delivery system before figuring this out.

Thanks to wankelnewbie for leading the way!