[Despotes]

I noticed a strong gas smell as soon as I got home yesterday evening from outside the car. Same smell this morning and it continued throughout the day today as I drove around for a few hours. Car runs fine-for 196K miles. No engine light. No noticeable leaks. The smell is not in the engine bay, but strongest somewhere in the mid section. A little gas smell, but not much from the gas cap.
Tomorrow, I'll remove some of the under plastic and snoop around some more. Evap canister cause a continued strong smell? I don't even know where that is located.
Any ideas?

 

[TalonTsi90]

You sure no one drilled your gas tank? Its been going on lately. Canister is back with the tank.

 

[tango]

Item 3 is the evap canister, or as Mazda calls it, the evaporative chamber. It is under the car at the rear, up against the fuel filler neck. So if you're smelling fuel towards the middle of the car this may not be the problem.

 

[Despotes]

I smell it from the center of the vehicle to the driver side rear wheel area. Strong smell when driving. I haven't overfilled the tank in a long time.
Are any of the fuel lines subject to corrosion?

 

[bulwnkl]

All metal items are subject to corrosion, all rubber items are subject to cracking and failure, and all items of any kind are subject to rubbing (like from vibration) wear-through.
Stick with your plan to pull the belly pan and you’ll likely find the leak.

 

[tickerguy]

Also pull the rear seat (its a couple of minutes) and the access panel; see if the pump flange is wet.

 

[Despotes]

It looks like the fuel is coming from the top of the tank. There's a small 6" ish opening underneath where I can see it's wet with gas. Only 2 levers and two bolts and the seat comes out.
--Part of the gasket is wet with gas. There's more wet gas on the lip of the tank.
Fuel Pump Assembly Retainer Ring - Mazda (GHP9-42-16X) and
Fuel Pump Assembly Gasket - Mazda (BBM2-42-166A?
Ordered the parts. Is it as simple as unscrewing the very corroded screws and replace?

 

[tickerguy]

Service manual says the screws come off, the top ring comes off, and then the pump lifts out. DO NOT booger the threads of the receiving flange under the assembly -- those are part of the tank and if you do you're buying a tank. In addition make VERY certain no dirt or other trash gets into the tank; clean around there thoroughly before you start taking things off as there is no easily-replaceable inline fuel filter on these cars.

It goes without saying be careful of potential ignition sources and spills -- there's obviously going to be gas in the bowl of the pump and the fuel level sensor is part of it, which will try to hang up (it'll clear, just watch it.) It looks like the leak in this case is between the flange (where the screws go into) and the top of the pump which implies the pump itself has a seal leaking somewhere (perhaps at the fuel outlet pipe, which is under pressure.) You'll probably need a disconnect tool to get that line off.

If the leak is at the top of the pump then its trash; its not very common for the seal rings on fuel pumps to leak at the tank/pump point -- it does happen but is not common. My money is on the seals at the top of the pump being toofed but its worth trying to clean it up and replace the seal and ring first as in-tank pumps tend to be a bit expensive.

 

[Despotes]

Could you provide a link to the right disconnect tool I'll need?

 

[tickerguy]

China Freight and the other auto parts places have a set; I don't know the exact size for these cars but they're fairly common. I have several in different sizes as this sort of connector is pretty common on vehicles in different places. They either come as two pieces you put together or has a split, you put it around the pipe and then you push it into the connector which releases the tangs that are in the connector and allows you to pull the hose off. Some makes and models you can squeeze the sides of the connector which will release it but this one looks like a tool-required one (much like most GM trucks are with their inline fuel filter.) It has to be the correct size or it won't work. DO NOT ATTEMPT TO FORCE THE CONNECTOR OFF; if you have the tool in there correctly it will not be hard to remove.

There are ways to get around having the tool but they're somewhat of a high-wire act and if you screw up the locking mechanism in the connector or damage the O-ring that's in there to provide the seal between the connector and the pipe you then get to buy a new hose and I'm not sure where the other end of this one goes or how much "fun" it is to replace. As such damaging that is to be avoided.

 

[Despotes]

Just found this video. Jump to 5:23. Looks like I don't need one.
HERE

 

[tickerguy]

Yep -- looks like on this car the top locking collar comes up and off it comes; no tools required.

The common factor with all these is that the connection is sealed with a small O-ring inside the connector; its possible that's where the leak is, but changing that O-ring, while likely possible, would require knowing exactly what the correct size is and, since the connector is plastic, getting it swapped without using metal tools that could damage the seating surface (which will make it leak.) Hopefully that's not where the problem is as while that O-ring is very cheap changing it would not be easy.

 

[Cdn17Sport6MT]

With all of that corrosion evident... i) how'd it get so much salt spray up there to cause all that rust?; ii) what crappy materials Mazda used 🙁; and iii) wondering if many/most of us should have a boo at ours and apply automotive wax-based rustproofer there?

 

[tickerguy]

I've dropped two GM truck tanks in the last year (there's no hatch on those, so it's a real "fun" job) to replace the fuel pumps which were getting wonky and likely were headed for an outright failure which of course strands you instantly and then mandates a tow as you're not fixing that on the side of the road. Oh, GM has a habit with some of their trucks of using a "captive nut" bracket that goes on the frame rail for the straps on one end which is wildly under-engineered in terms of retention (and no, in the years since manufacture they haven't improved the replacements either) so when you go to take it apart its virtually guaranteed the nut will spin in said bracket which means you get to drill the head off the bolt.

Quite a decent amount of dirt and such gets up in there; both were absolutely filthy on the top of the tank and around the pump and connections. Be glad that on these cars and most others there's a hatch....

 

[Despotes]

The screws are very corroded. I hope the screw holes don't go completely through the tank. They're soaking in PB blaster right now. I cleaned everything the best I could, but there's so much rust I'd be surprised if nothing gets in the tank.
The leak is definitely coming from the gasket--lower right in the pic. Started it up and saw the gas seeping from that area.

 

[Archerfish]

I hope you will be able to make a detailed instructions on how to repair that thing, with lots of pictures.

 

[Despotes]

Just ordered screw extraction kit. Prepping for the worse.

 

[tickerguy]

There's no fuel there on a static basis with the vehicle not moving (you'll see when you get it apart); the vent is below that level. I don't doubt the source, but that's almost-certainly the pump and not the gasket (which is UNDER the pump; the ring on top holds the pump against it and thus makes the seal.) I wouldn't be even a bit surprised if there's a corroded hole in the pump body at the top above the gasket level; when these pumps are running they fill the bowl that then spills back into the tank, which is how they cool the motor and pump assembly.

Expect to replace the pump itself; once you get it apart and cleaned up I bet you'll be able to see where the leak source is.

 

[Cdn17Sport6MT]

The screws are very corroded. I hope the screw holes don't go completely through the tank. They're soaking in PB blaster right now. I cleaned everything the best I could, but there's so much rust I'd be surprised if nothing gets in the tank.
The leak is definitely coming from the gasket--lower right in the pic. Started it up and saw the gas seeping from that area.

All the more indication that those of us whose cars are not in this state yet ought to rustproof this area. Likely very crappy cad-plated cpts that rust almost immediately 😐.

 

[mmmmark]

Is the tank under pressure? If so, wouldn’t the air find the hole and gurgle out some moisture? Just looking for a possible reason it would not be a gravity leak. <shrug>