CX-9 hard to start after fillups

goodtexan

Member
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Mazda CX-9 2012 Grand Touring
My 12 CX-9 has a hard time starting each time I fill it up. I have to crank it for a few seconds to get it to starts. Then it won't stay started the first couple of times. Finally I rev it up and get it in gear to leave the station. Also, it has stalled a couple of times when traffic comes to a stop. And at a stop light, sometimes the tach moves around a bit other times steady. The check engine light came on for a day after it stalled twice. Had the code read. The guy at O'reilly, https://www.oreillyauto.com/, said both O2 sensor banks were showing the car is running rich or tricking it to run rich.

I read on the web that the hard starting after fill ups could be due to the purge valve being stuck open letting fumes into the cylinders.

Has anyone had experience with these issues? I'm going to take it to the shop Monday.

112K miles, owned for less than a month
 
My 12 CX-9 has a hard time starting each time I fill it up. I have to crank it for a few seconds to get it to starts. Then it won't stay started the first couple of times. Finally I rev it up and get it in gear to leave the station. Also, it has stalled a couple of times when traffic comes to a stop. And at a stop light, sometimes the tach moves around a bit other times steady. The check engine light came on for a day after it stalled twice. Had the code read. The guy at O'reilly, https://www.oreillyauto.com/, said both O2 sensor banks were showing the car is running rich or tricking it to run rich.

I read on the web that the hard starting after fill ups could be due to the purge valve being stuck open letting fumes into the cylinders.

Has anyone had experience with these issues? I'm going to take it to the shop Monday.

112K miles, owned for less than a month



Pull Codes. If you see codes related to the EVAP system, it could be that you have overflowed the tank one too many times during refueling, causing problems with the charcoal canister or the charcoal pellets inside the canister (to be more precise). Could be a clogged charcoal canister, or yes - the purge value solenoid could be faulty. Again, check for codes related to the EVAP System.
 
Pull Codes. If you see codes related to the EVAP system, it could be that you have overflowed the tank one too many times during refueling, causing problems with the charcoal canister or the charcoal pellets inside the canister (to be more precise). Could be a clogged charcoal canister, or yes - the purge value solenoid could be faulty. Again, check for codes related to the EVAP System.

I had it checked and they did say the canister and purge valve needs replacing. Is that something than can be done at home? I do my own brakes, oil and other maintenance.
 
Why are there two purge valves? This Dorman part looks like the one I have on the firewall.
https://www.autozone.com/emission-control-and-exhaust/canister-purge-valve/dorman-canister-purge-valve/907834_0_0
But also there is this one that all the parts places say is it: https://www.autozone.com/emission-c.../duralast-canister-purge-valve/849669_0_12209

They are both called canister purge valves. But I see the first one in my car so that must be it. Did Mazda use two different types? Even a Mazda dealer says I need the second one. They call the first one a vacuum tube assembly.
 
Go here: http://www.aa1car.com/library/evap_system.htm

Scroll down about halfway to the OBD2 evaporative emission system diagram. There are two solenoid valves, the purge valve and the vent valve. The purge solenoid is the one under the hood. The vent solenoid is back by the canister (near the fuel tank).

Did you get a copy of the codes? You can swap the purge valve pretty easily, but there is a diagnostic procedure in the service manual that you might want to look at before you start swapping parts. You could have a leak somewhere in the EVAP system.
 
I had it checked and they did say the canister and purge valve needs replacing. Is that something than can be done at home? I do my own brakes, oil and other maintenance.

It is not that difficult a repair in most cases - though I like to put the vehicle on a rack instead of laying on my back. However, I don't know the layout of your year and therefore can't tell how difficult it would be to get to both parts. I'm also guessing that "they" already ruled out a Voltage problem in the wiring and/or connectors involved with the purge valve itself? To truly troubleshoot the problem, I would think they'd want to know that information before swapping parts. Anyway, for any DIY that I've never done before, I'd want/need a parts layout and diagram identifying all components involved in the repair. However, many EVAP systems are so generic, that you might be able to glean enough information about how to do the repair from online videos of mechanics having done it before. There are plenty of those out there.

You will also want a good site to use as a parts reference such as: https://www.onlinemazdaparts.com. You want to at least be able to locate the necessary parts on your own and identify them independently, so that you can have a focused conversation with your mechanic about specific parts and why it is necessary to replace them.

Here: https://www.onlinemazdaparts.com/a/Mazda_2017_CX-9-Signature-AWD/_53898_7066851/EMISSION-COMPONENTS/5331285.html you can see the "Vapor Canister" for the 2017 CX-9 (same as 2018, which is what I have). That's the so-called "Charcoal Canister." Just below it, you see the "Secondary Air Injection Control Valve. Vapor Canister Purge Solenoid." That's the "Purge Valve." Point being, you can see the entire system and all is Emission Control components (along with retail prices) with a site like this. There are others as well for Mazda Parts.

I had to replace the Canister on the vehicle I just sold last year because I overfilled the tank too frequently and that caused problem with the charcoal pellets inside - clogged the entire system and after refueling, the car would simply shut down or just not start at all for several minutes. One of the other symptoms includes the fuel pump itself constantly shutting down during refueling operations. If the pump continuously shuts down during refueling, that could be because the pressure inside the system is too high as a result of a malfunctioning EVAP system (clogged vent hose, failed purge valve, failed purge valve connector/harness, etc.). Something inside the EVAP system has failed completely or is in the process of failing one way or another.

All the best with this repair.
 
I replaced the purge valve. Mazda Purge Valve.jpg This is what mine is like. On the firewall. It comes with the hoses attached.

Filled up the next morning and the car started right away. It runs smoother and the codes are clear. I still want to replace the charcoal canister.

Thanks for all your help and the replies.
 
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I replaced the purge valve.View attachment 218483 This is what mine is like. On the firewall. It comes with the hoses attached.

Filled up the next morning and the car started right away. It runs smoother and the codes are clear. I still want to replace the charcoal canister.

Thanks for all your help and the replies.

Glad you nailed it. Congrats on the success!
 
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