Protege5 won't idle after refueling (EVAP/O2 sensor issue?)

[BenjiHoggi]

I'm having weird idle issues with my P5 right now. Wondering if anybody has suggestions.

• It started with a P0440 code that would pop up every day or two and I would just clear. I did this for several weeks.
• Replaced the EVAP solenoid commonly related to this code under the hood with an OEM Mazda part off eBay. Code went away and has not come back, but sometimes the solenoid just clicks on and off rapidly while the car is idling (and stops when I unplug it)
• At some point recently the RPMs started to suddenly dip at idle with the car almost dying but catching itself. Felt like a misfire too sometimes but would run fine when driving. Browsed around on here and decided to check O2 sensors.
• No codes for O2 sensors (or at all) but I ran an OBD2 scanner and compared the voltages for both sensors and the upstream was a little weird. I replaced the downstream a few years back with a genuine Denso OEM unit but haven't touched the upstream. Here are some screenshots of the data. Sensor 1 (upstream) seems all over the place.
  
  
  
  
  
• Figured bad O2 sensor but it idles fine most of the time and then will have an episode of bad idle every couple days or a week. Pulled the upstream sensor and soaked it in gasoline to try to revive it. No change.
• Most recently (last 3 or 4 times) I've filled up at the pump, the car has died the first time I try to start after filling up. This last time, it would not stay idling and was barely running and I had to keep my food on the accelerator to keep it from dying. It did this for a few minutes and then went back to normal.
• Additional data: Every few months I get the EGR code for insufficient flow. I've cleaned the EGR once but couldn't clean the whole pipe (couldn't get it off) and the code still intermittently shows up. I know it also effects idle, but haven't seen the code in at least a couple months now.

The bad idle is starting to become a real problem, and now I don't know if this is related to EVAP, or fuel, or the O2 sensor, or something else like the fuel pump or EGR. Any suggestions?

 

[pcb]

Look into your fuel pressure regulator solenoid valve and its connected components.

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LankyKiwi's Rally-flavored SP20

It's very nice :) nearly no rust to deal with either! Although it's hitting mid 30 degrees with near100% humidity lately :( Don't forget to add that's 30 deg Celsius. Our North American friends use that stupid Fahrenheit system *. And yes, 20+ years now and our cars have hardly any rust on...

mazdas247.com

 

[BenjiHoggi]

Look into your fuel pressure regulator solenoid valve and its connected components.

​

LankyKiwi's Rally-flavored SP20

It's very nice :) nearly no rust to deal with either! Although it's hitting mid 30 degrees with near100% humidity lately :( Don't forget to add that's 30 deg Celsius. Our North American friends use that stupid Fahrenheit system *. And yes, 20+ years now and our cars have hardly any rust on...

mazdas247.com

Will do, thanks as always PCB! Haven't done any further diagnosis yet but will definitely update when I have more info to share.

One notable thing - EGR CEL popped up again. Might order some parts to do a more thorough refresh of that while I'm at it. Not related though probably.

 

[pcb]

One notable thing - EGR CEL popped up again. Might order some parts to do a more thorough refresh of that while I'm at it. Not related though probably.

You are aware of the "Canadian" EGR with the coolant lines right ??
It's not listed for the P5 at Rockauto, but it is for the 2.0L Protégé.

PS,.. It has nothing to do with Canadian emissions. Is has more to do with our generally colder climate.
Exhaust gases condense on a cold EGR, gumming it up.
Once you start burning oil, tar builds up in the EGR.
The "Canadian" version is heated.

 

[BenjiHoggi]

The issues persist so I'm digging into this a little more. I did some research (i.e. googled and asked the AIs ) and it just doesn't seem completely likely that the fuel pressure regulator solenoid itself is the problem.

The explanations I saw for why the car would have trouble with idling and starting after fueling up is that while fueling, the engine can fill with fuel vapors if the purge solenoid isn't working properly to keep the vapors in the tank. This would cause the engine to have trouble idling for a minute while the vapors escape.

I just replaced the purge solenoid to fix my P0440 code, and while I no longer get the CEL, I do sometimes hear a constant repeated clicking noise from solenoid which I didn't hear before, and makes me wonder if it's not working even though it's a brand new Mazda part. I feel like that would throw a CEL. But the fueling-stalling issue didn't start until after I replaced the purge solenoid.

I've also been getting pretty crap gas mileage, like 24-26 MPG with mostly highway driving. I used to average a VERY consistent 28-30 MPG with the same exact commute.

Thoughts?

 

[BenjiHoggi]

Okay this has become a REAL problem now. Symptoms and diagnostic steps so far:

• P0455 early on (or P0440? don't remember), came back every time I cleared it. Replaced the purge valve solenoid and it went away. But the solenoid sometimes just clicks in the bay so don't know what's wrong there.
• Car will not idle when filled with gas. Have to put the accelerator to the floor to start it and keep my foot on the gas for several minutes to keep it idling.
• There seem to be fuel vapors in the intake. When I started it today at the gas station, it backfired violently and blew the air filter box open. Broke the tabs holding the box down and hit the underside of the hood. So loud it made a stir at the gas station.
• MPGs are terrible - just got back from a trip with mostly 70MPH highway driving and my MPG was 26. I noticed it drop rapidly around the time that I started getting the evap CEL.
• Replaced the Fuel Pressure Regulator, no change.

I also have an occasional idle drop or stutter. Replaced upstream O2 sensor with genuine Denso and replace downstream with same a few years back. I'm pretty sure it's my EGR, and I've gotten an occasional insufficient flow code over the years. But worth mentioning.

I've been reading and found some useful info.

Solenoid question

hi, so ive had this faulty canister vent solenoid valve for few months, its reduced by mpg by atleast 7 or 8, and i drive ~100km daily, i tried sourcing from local junkyards but none have any 2002 p5, so I called the dealer, gave me a 250$ price for a new valve, and he told me the valve was...

mazdas247.com

Seems like a Canister Vent Solenoid could be something to look into.

Need to do some diagnostics I guess. I'll use this to document as I learn and hopefully fix things, but if anybody has suggestions or experience, that would be helpful too.

 

[pcb]

You may have overfilled your gas tank and sucked liquid gas up into catch tank in the engine bay.
The purge solenoid valve opens up and sucks in raw gas instead of gas vapor.

One guy did that and he said his catch tank was gurgling like a bong.
He removed his catch tank, drained it, reinstalled it and all was well.

You might have a bad purge solenoid valve now if you did suck raw gas through it.


Remember to always stop pumping your gas when the gas pump nozzle shuts off.
Don't even round it up to the next nickel.

It's a common problem with our car.

It blowed up, blowed up real good!

#Shorts SCTV Farm Film Report:

youtu.be

 

[BenjiHoggi]

You may have overfilled your gas tank and sucked liquid gas up into catch can in the engine bay.
The purge solenoid valve opens up and sucks in raw gas instead of gas vapor.

One guy did that and he said his catch can was gurgling like a bong.
He removed his canister, drained it, reinstalled it and all was well.

View attachment 324605

You might have a bad purge solenoid valve now if you did suck raw gas through it.


Remember to always stop pumping your gas when the gas pump nozzle shuts off.
Don't even round it up to the next nickel.

It's a common problem with our car.

It blowed up, blowed up real good!

#Shorts SCTV Farm Film Report:

youtu.be

Hmm. I pumped gas at the same station I usually go to, pulled it out when it clicked, and otherwise filled it normally. I've had gas attendents top it off well past that and never had problems. So I'm still inclined to think it's the evap issue, though I'm sure things may have gotten a little bunged up with the backfire.

Regardless, it's something I'll investigate, and I appreciate the feedback. I guess that's what I'll be doing for my post-Christmas weekend.

 

[pcb]

When you overfill the gas tank, raw gas gets sucked into tube "A" in the diagram, then it gets into your Evap system.

Then it gets sucked through the Evaporative Gas Check Valve (two-way) as a liquid.

Then it fills up your air filter, then goes through the CDCV it's on it's way to the charcoal canister, then through the evap line into your catch can and directly into your intake.

The Filter, Canister and Can could all have varying amounts of liquid gas in them because they do dry out in time as air goes through them and vaporizes the liquid gas.

Or they could perhaps plug up with liquid gas if there isn't enough vacuum pressure to draw liquid gas through the system.

Or a valve could get stuck or open or closed but that should pop a code unless they just leak?

 

[pcb]

That Evaporative Gas Check Valve could be an issue and I don't think that there is a code for it?

I remember a guy that had the vent holes on the valve plugged up with mud and his car ran like crap.

IIRC, the valve directs gas vapor directly to the Catch Tank in the engine bay when the engine is running, then switches to sending it to the Charcoal Canister when the engine is shut off.
Something like that.
The CDCV valve also directs air through the Charcoal Canister to suck the vapors out.

I never really fully understood the vapor flow diagram.

 

[BenjiHoggi]

Okay, figure I should update this, as there have been some changes.

As I described in my previous posts, I thought the Canister Vent Solenoid was a potential culprit. I checked this and it seems to operate perfectly. I pulled it apart, cleaned it, actuated it using an alternative 12v source. No issues

So I just decided to ignore the problem between fuel fill-ups.

I started to suspect the fuel pressure solenoid though, even though I replaced it last summer. This problem started around the time I swapped it. The old solenoid popped a CEL but worked fine otherwise. The new solenoid was an OEM part in OEM packaging off eBay and didn't throw a CEL but would sometimes click repeatedly in the engine bay with the engine on. So I suspected this could be the problem. I checked vacuum lines for any kind of leaks and didn't see anything.

Eventually, I decided to just swap the fuel pressure solenoid with the old one. Annd now my car idles fine after fill up. And the check engine light is back on. So I'm stumped but happy to have a usable car again.

Fuel economy is still trash, but I'm guessing that is more or less unrelated. I probably should replace the fuel pressure solenoid with a proper one off RockAuto but I'm becoming very fatigued by this car and I don't want to dump more money into it right now...just had to replace a battery and an HID headlight ballast.