'99 Mazda B2500 charcoal canister replacement: tips and cautionary advice welcome

[1999Mazda Central Florida]

My fuel fill ups have been gradually getting more and more annoying as the gas pump shuts off (pressure build up) after only a slight amount. After searching around a bit more and describing the situation to a mechanic I was informed that the charcoal canister is likely the culprit. I'm getting no engine light on or codes indicated when checked. I want to try and replace the canister myself but wanted to run it by someone who may have done in before. Murphy's law has a way of popping up on me and want to try and do it right without destroying any fittings or having to hack saw something off etc. Pics attached show a "Y" adapter and special fittings. Also, I understand a "smoke check" may be done to I.D. a leak (small cracked in hose etc.) but it may be my issue is something is clogged/blocked. The location for canister on 1999 is different from 1997 so wanted to check on the forums to double check. Great forum and thanks in advance.

 

[Colin]

I'm jealous of the complete lack of rust, should be an easy job. Does that y connection turn into the silver fitting further down? Should just need the AC line disconnect tool set for that, they're pretty cheap. Is that the only line connection on the canister?

 

[89Twincharge]

It may actually be the selenoid or the pressure sensor... some universal scanners dont pick up evap codes... is gas pump just clicking off or is gas spraying out? Next time you fill up leave ignition on and see if it act the same... also if someone attempted to steal gas they may have knocked the anti siphon device loose which can do similar things. Actually had one like that in our shop during the gas crisis of '21 lol

 

[1999Mazda Central Florida]

I'm jealous of the complete lack of rust, should be an easy job. Does that y connection turn into the silver fitting further down? Should just need the AC line disconnect tool set for that, they're pretty cheap. Is that the only line connection on the canister?

Sorry for delay in reply: I was wondering about that if I needed a special tool for that. No silver fitting further down.

 

[1999Mazda Central Florida]

It may actually be the selenoid or the pressure sensor... some universal scanners dont pick up evap codes... is gas pump just clicking off or is gas spraying out? Next time you fill up leave ignition on and see if it act the same... also if someone attempted to steal gas they may have knocked the anti siphon device loose which can do similar things. Actually had one like that in our shop during the gas crisis of '21 lol

Sorry for delay to reply: Yes pump handle clicks off (no gas splash.) I have monitored with ignition on and acts the same. In past I have (ignorantly) filled all the way to the tip top trying to get as much gas in as I could, not knowing this puts gas into the charcoal canister and clogs it up. Just wondering what kind of fitting that is. I may try to test the pressure sensor after removing canister.

 

[Colin]

Sorry for delay in reply: I was wondering about that if I needed a special tool for that. No silver fitting further down.

...
the single line coming out of the "y", is that the line that goes into the canister?
You either just need to squeeze that clip with your fingers, or you need a set of disconnect tools like this

 

[1999Mazda Central Florida]

...
the single line coming out of the "y", is that the line that goes into the canister?
You either just need to squeeze that clip with your fingers, or you need a set of disconnect tools like this

View attachment 61112View attachment 61112

Yes I believe so: single line from "Y" to canister with that clip/connector. I'll take a closer look at it tomorrow.

 

[89Twincharge]

Yeah that is a squeeze connector... hit it with brake clean before you try and remove it. If you ever fill that will happen... junk yard be a good place to get one I dunno if they offer those at parts stores any more

 

[Woogie]

Have you checked the fuel filler neck hose for cracks? That's a very common cause for the pump kicking off. Gas pump handles have a mechanism that senses displaced air flowing out of the tank as gas goes in. Usually once the gas reaches the top of the tank, the air flow stops and the pump cuts off. If there are cracks the air will go out the cracks instead and with no air coming out of the gas tank the pump thinks it is full and shuts off prematurely.

My '95 has the exact same symptoms. Gas pump kicks off every few seconds. I know it's not the charcoal box getting flooded because on this vehicle it's way up near the battery. I'm replacing the hose, vapor vent valve and its seal as soon as the parts all come in.

Not saying it isn't the charcoal box, but take a good look at the filler neck hose first. It is a known failure point on older Rangers and B series.

 

[Woogie]

Got my parts in today and pulled the filler neck. I looked at it with a borescope before ordering and didn't see anything but figured it was due for replacing. Lifted the bed, still didn't see anything. Thought about leaving it and looking elsewhere but since I had the hose already I decided to go through with it. It wasn't until I had the hose off that I found these hiding on the end that goes into the tank on the side that faces the cab.



Put the new hose on. Also replaced the vapor vent valve and the seal that goes on it. The hose was unplugged and there were rocks and dirt in it.

Went to the gas station and filled up after everything was back together. No more filling problem. Check yours. Spend the extra money on a quality hose that is rated for fuel and not the cheap ones.

 

[1999Mazda Central Florida]

Got my parts in today and pulled the filler neck. I looked at it with a borescope before ordering and didn't see anything but figured it was due for replacing. Lifted the bed, still didn't see anything. Thought about leaving it and looking elsewhere but since I had the hose already I decided to go through with it. It wasn't until I had the hose off that I found these hiding on the end that goes into the tank on the side that faces the cab.

View attachment 61453

Put the new hose on. Also replaced the vapor vent valve and the seal that goes on it. The hose was unplugged and there were rocks and dirt in it.

Went to the gas station and filled up after everything was back together. No more filling problem. Check yours. Spend the extra money on a quality hose that is rated for fuel and not the cheap ones.

Thanks Woog! Sorry for dealy to reply...Is that pic. at the top of the filler (up by the filler cap?) Or, as you say it is the tube that goes into the actual gas tank? Looks like it's where it connects way down by the tank. I will certainly go with good quality parts for this as you suggest and also what is the vapor vent valve (up by the filler?) where gas cap is?

 

[Woogie]

Yeah, it's part 8 on the numbered diagram. The pic I posted is from my 95 and is from the end that goes into the tank. The 99s had a different design where the first bend is metal and the rubber part is shorter and has a 90 degree turn. The air escape goes up a separate hose instead of having one inside the other. Inspect both hoses and the metal part of the neck for holes as they can rust out.

Filler Neck Supply should have what you need. I've heard good things about them but I ended up having to buy a Spectra hose because they were out of stock on my year.

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Make sure you double and triple check your existing parts and the measurements on the product because there are different parts depending on the bed.

 

[1999Mazda Central Florida]

Yeah, it's part 8 on the numbered diagram....
Thanks, I'll check that out...it may be that tube is the issue and not the charcoal canister as you said.