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Discussion Starter #1
Hi all,

I've been wanting to replace the purge control valve on my 2008 Mazda 3, 2.0 engine.
After doing my homework, reading about parts, tutorials etc, i ordered one for my car.
105840


However, it doesn't fit my car! I traced the lines to the valve, following a how to from here, and other sites. The one pictured above, is simply not in my car, neither is that rubber ring it is placed into. The plug is different too and does not fit.

After locating it, it looks like i have one fitted for a 2010-2013 Mazda 3, pictured below.
105841

It's named a vapor canister valve on a popular webshop.

What's going on here? Did Mazda use multiple purge valves in the 3? Should i just buy the 2010-2013 one and slap it in?

105842

This is a pic from my car. Couldn't read a part number on it.
 

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Hi all,

I've been wanting to replace the purge control valve on my 2008 Mazda 3, 2.0 engine.
After doing my homework, reading about parts, tutorials etc, i ordered one for my car.
View attachment 105840

However, it doesn't fit my car! I traced the lines to the valve, following a how to from here, and other sites. The one pictured above, is simply not in my car, neither is that rubber ring it is placed into. The plug is different too and does not fit.

After locating it, it looks like i have one fitted for a 2010-2013 Mazda 3, pictured below.
View attachment 105841
It's named a vapor canister valve on a popular webshop.

What's going on here? Did Mazda use multiple purge valves in the 3? Should i just buy the 2010-2013 one and slap it in?

View attachment 105842
This is a pic from my car. Couldn't read a part number on it.
I had the same issue lol....

the Part# for the last 2 pics is "L518-18-741"
 

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Discussion Starter #3
Thanks for your reply.

I'm still a little confused.. The purge valve in my car, 2nd picture in my first post L518 18 741 doesn't come up anywhere for a '08 2.0 engine. Only for 2010 and up, and for the '08 2.3 engine.

Also there's another purge valve? What's the difference between them? Are they both doing the same thing?

105843

105844


To be clear, both of these are in my car, '08 2.0 engine. Both are purge valves apparently, what's the difference between them? The second one I can't find anywhere, only for '10 and up, and for a '08 2.3 engine.
 

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The first one isn't a purge valve, it's the intake runner control and swirl flap vacuum solenoids. As for the valve you have not showing up for your car, cross refferces are known to have errors or be outright wrong. If you are worried about getting the correct purge valve, just go to the Mazda dealer and give them your VIN number.
 

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Discussion Starter #5
The first one isn't a purge valve, it's the intake runner control and swirl flap vacuum solenoids. As for the valve you have not showing up for your car, cross refferces are known to have errors or be outright wrong. If you are worried about getting the correct purge valve, just go to the Mazda dealer and give them your VIN number.
Thank you for your answer. :)
I'm sure i have found the right purge valve, part numbers are exactly the same. I was just wondering why this one doesn't come up anywhere as fitting for a 2008 2.0 engine.

As for the other 2 on the metal bracket, why are they named purge valve(s) on every webshop i visit, if they're not purge valves? Are they part of the evap system? ( I haven't read into it after your post)
 

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The purge valve is part of the EVAP system, those two solenoids are not. They move vacuum operated valves in the intake manifold. Whoever listed them as purge valves are idiots. If you look up IMRC solenoid you'll find a bunch of them.
 

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Discussion Starter #7
The purge valve is part of the EVAP system, those two solenoids are not. They move vacuum operated valves in the intake manifold. Whoever listed them as purge valves are idiots. If you look up IMRC solenoid you'll find a bunch of them.
That's great information, thank you. :)

Another question i have, i have troubles filling up on gas in the winter, often it spits gas straight out again. No issues in summer however. Could that be related to the purge valve? I've also read about a vapor canister vent valve, but again, no webshop has one for a 2008 model, only 2010 and up. Is this vent valve in my car? Is it possibly the same as a leak detection pump, that's apparently very well hidden in the rear end?
 

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Your car has a leak detection pump based EVAP system. These systems don't have a vent valve or really an equivalent part. The purge valve isn't the issue. I've had issues filling my 08 3 in the winter from time to time too. Cleaning the vent filter helped. It's attached to the fuel filler neck which is behind a plastic shield in the right rear wheel well. I think ultimately the issue with mine is a partially clogged charcoal canister which is a pain to replace so I just haven't gotten around to it.
 

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Discussion Starter #9
Your car has a leak detection pump based EVAP system. These systems don't have a vent valve or really an equivalent part. The purge valve isn't the issue. I've had issues filling my 08 3 in the winter from time to time too. Cleaning the vent filter helped. It's attached to the fuel filler neck which is behind a plastic shield in the right rear wheel well. I think ultimately the issue with mine is a partially clogged charcoal canister which is a pain to replace so I just haven't gotten around to it.

Awesome, thank you.

I know about the filter, you're talking about the one in the rear right wheel well, right? Every winter when it starts to reject gas (3 so far) i've taken it out, cleaned it, dried it, and put it back. Every time it was frozen solid with ice/slush. Cleaning always did the trick, untill this winter. Even tried without the filter in it, still won't take gas on cold days. I can only get gas in on warmer days, when it gets around zero. When it gets close to -20 it won't take any at all. Had someone suggested to blast the line with compressed air, what are your thoughts on that?

Edit: Wanting to replaced the purge valve for a little rough idling and a CEL, P0446.
 

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It sounds like there is moisture somewhere in the EVAP system and it's freezing, preventing the system from venting properly when you go to fill up. The code is a bit odd given that I thought these cars don't have a vent valve, maybe I was rembering it wrong. I doubt that the purge valve is going to fix the P0446. How did you determin that it's the source of your rough idle? Did you disconnect the line going to the purge and cap off the end going to the intake manifold? If the purge valve is the cause then doing that test will fix the idle immediately.
 

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Discussion Starter #11
It sounds like there is moisture somewhere in the EVAP system and it's freezing, preventing the system from venting properly when you go to fill up. The code is a bit odd given that I thought these cars don't have a vent valve, maybe I was rembering it wrong. I doubt that the purge valve is going to fix the P0446. How did you determin that it's the source of your rough idle? Did you disconnect the line going to the purge and cap off the end going to the intake manifold? If the purge valve is the cause then doing that test will fix the idle immediately.

Well, so far i've spend a couple hundred in diagnosing the filling issue and the CEL at different shops, and so far no one has been able to pinpoint and fix the exact problem. I've been reading into it for a little while now, and everywhere i read P0446 could be caused by or related to a faulty gas cap, purge valve, charcoal canister, evap system hose, fuel filler neck, and fuel tank sending unit.

I've replaced the gas cap last year, and that didn't make any difference. It may very well not be the purge valve, as I don't have all the symptoms, but since a new one is only $30, i might as well just replace it and see what it does. It still is the factory original one and apparently they are notoriously for going bad? I have not disconnected it as you said, i could try that first.

My OBD scanner does have some options to test the evap system, and it says "pass" on every one.

Evap system (mode$8)
Evaporative system leak test passed.

Evap monitor 0.090"
Pass

Evap monitor 0.040"
Pass

Purge flow monitor
Pass

The monitors show a value in mA, but all of them are 0.000. Not sure what that tells me?
 

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P0446 means you have an electrical problem so any non-electrical parts are generally ruled out. Gas cap, charcoal canister, evap system hose, and fuel filler neck are not the issue. If I had to guess I would say it's probably the leak detection pump or wiring to it.
 

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P0446 means you have an electrical problem so any non-electrical parts are generally ruled out. Gas cap, charcoal canister, evap system hose, and fuel filler neck are not the issue. If I had to guess I would say it's probably the leak detection pump or wiring to it.
So if i'm correct, fuel vapors are going trough the charcoal canister, which has 2 vent lines. One goes to the purge valve, purging vapors into the engine when it opens. The other vent line goes to the leak detection pump, which should be open under normal circumstances, letting vapors trough and exit the system trough that filter in the rear wheel well, correct? It only closes when the the car is testing the evap system by pressurizing it, right?

That means if my leak detection pump is not functioning and shut closed, or clogged up or whatever, fuel vapors have nowhere to go when you fill up, and fuel comes back out the filler neck.

105851
 

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That's how it looks in that diagram. The vapors also have to flow through the charcoal canister before they reach the leak detection pump so that could also be a source of the blockage.
 

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So i have replaced my purge valve, and i think it's safe to say that it fixed my P0446 code. Put over a 1000km on it, and the CEL still hasn't come back on, whereas before it would come back on after about 200km. And it idles definitely a lot smoother. Little odd still though, put 12V to the old one and i could hear it click?

I also ended up replacing the two valves on the bracket, the IMRC and the VIAS. Made a slip with a wrench, hit the vacuum lines and broke 2 hose connectors clean off. Replaced the whole assembly with one from a scrap car.

It does seem to take fuel slightly better, but it's still a pain in the butt.

Is there anyway to test the leak detection pump without taking the whole rear end apart? Apparently it's somewhere right above the subframe?
 

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At minimum you would need to disconnect it from the charcoal canister and try blowing through it. It should be visible from the right rear wheel well, mounted to the sub-frame.
 

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It's been well over 2000km now, and still no CEL came back on. So can definitely say now that replacing the purge valve fixed that issue. Fuel economy has improved as well.

Now, if the leak detection pump was bad, or not functioning for whatever reason, wouldn't that trigger a CEL? Since it's a vital part of the emission system?
 

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It should trigger it though specific conditions need to be met for the PCM to run a full self test on the system though the full test usually isn't required to detect electrical issues. There can also be cases where a clog isn't bad enough to trip the light but is enough to prevent filling the tank. All the PCM typically looks for is that the EVAP system holds vacuum for a specified amount of time and can equalize/release that vacuum completely in a specified amount of time, you can do both of those with a partially clogged system.
 
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