known problems of Mazda skyactiv 2.5 hard re-starting?

[t1snwrbrdr12]

Long term fuel trip was about +4.6% on my highway cruise into work. Short term fluctuated based on load from -3% to +3%. While hot in park idled up long term went +2% to zero short term +1 to -3%

I initially thought leaking injector but so far I have not caught any data to support that. Fuel rail pressure rises on shut down as opposed to drop which would indicate nothing is leaking down.

 

[goingplacesanddoingstuff]

Long term fuel trip was about +4.6% on my highway cruise into work. Short term fluctuated based on load from -3% to +3%. While hot in park idled up long term went +2% to zero short term +1 to -3%

I initially thought leaking injector but so far I have not caught any data to support that. Fuel rail pressure rises on shut down as opposed to drop which would indicate nothing is leaking down.

I might fill up with higher octane fuel from a different vendor and run a bottle of Techron through it. Drive hard with several highway stints. See what that does.

 

[Andyd95]

New MAF……. or cleaned it with electronics spray cleaner ?

We have a CX5 with 130K miles. Time to clean.

New OE MAF

Funny thing was made a minimal change to the g/s - looked fine before and fuel trims were good too.

 

[goingplacesanddoingstuff]

This is a “did you plug it in?” question… but have you checked to make sure your engine air filter is seated correctly and the air box is sealing properly?

 

[Marcozi]

Long term fuel trip was about +4.6% on my highway cruise into work. Short term fluctuated based on load from -3% to +3%. While hot in park idled up long term went +2% to zero short term +1 to -3%

I initially thought leaking injector but so far I have not caught any data to support that. Fuel rail pressure rises on shut down as opposed to drop which would indicate nothing is leaking down.

Those FTs are fine.

 

[t1snwrbrdr12]

This is a “did you plug it in?” question… but have you checked to make sure your engine air filter is seated correctly and the air box is sealing properly?

I’ll poke around next time I am undehood, but this is been going on off and on for a year or more. It started and stalled 1 time which made me gain traction to think about looking into it. I’m pretty in tune with my cars so figured whatever is happening will set a fault soon, just didn’t expect it to start and stall before it’d set a code to lead me in some direction. And the past week it hasn’t had the issue of course, since I’m driving around with a scanner waiting to catch it (not that I’d even definitely be looking at the right live data at the time it acts up, but it’s so intermittent that I just haven’t experienced it this week).

 

[thickvthin]

I am going to have to do this purge valve check on my truck since i have hot start issues very similar to yours.
1. With cold engine, unplug the purge valve solenoid from the fuel tank side.
2. start engine (cold)
3. put finger on disconnected end on purge valve to feel a vacuum. One should not feel a vacuum at all.It should not be pulling any vapors from canister at cold engine. If one feelsa vacuum as soon as you start a cold engine, then that indicates a stuck open purge valve.
4. As engine warms up to normal temperature, it is ok to have a vacuum asengine is sucking in vapors to burn in engine.

this is my understanding on how to check for air or fuel vapors entering engine unmetered via the canister purge solenoid without a smoke machine.

 

[Aichiguy]

How's the air filter?

 

[thickvthin]

my air filter is new. did not solve hot start issue. i dont know about op. i am checking air idle control valve also.

 

[KrisZ]

I would check the purge solenoid valve. If it’s stuck open, it creates a vacuum leak, which would explain low idle and longer cranking times.

 

[bdc101]

Hey, i'm late to the game here (just signed up for BITOG for the first time) but just wanted to say I am following.

I bought a new Mazda6 6MT in 2014 (model year 2015). I am at 98k miles now and have not ever experienced this problem. The only time I had anything like this happen was in 2017 when the battery was slowly dying, and there was a TSB that had to do with the alternator not charging the battery enough. Since I had the TSB done I've never had the problem again. I assume your 2017 probably had that fix from the factory, and you said you checked the battery already. So I don't have any good feedback other than I'm following the thread.

(BTW the state of Mazda forums sucks. Very disappointing)

 

[2017Mazda3]

I’m not on any Mazda forums so I'm just sticking it out there to see if anyone has any knowledge of this issue, or access to Identifix and is curious enough to look it up.

I have a 2017 Mazda 6 2.5 skyactiv direct injected.

I’m sure it’s due for valve cleaning, although Mazdas supposedly don’t gunk up the valves even with gdi due to some magic they work in the heads and air velocity and temps or whatever. Regardless, valve cleaning has not been done.

115k on odometer. 5k religious oil changes since new (I’m original owner). It doesn’t use any oil. Clean the throttle body and replace the engine air filter around every 15k. Run Costco top tier almost every fill up, I’d say 90% of the time. Plugs replaced with the same exact as oem at 100k just for maintenance (I wasn’t aware they call for them at 75 or 80k or whatever it is). Old plugs looked fine, nothing alarming at all. It was doing this hard start at times then too I remember, and I had hoped it was because I ran over the plug interval. They are not from Mazda (they are from RockAuto).

I drive it pretty easily, an easy 25-30 mile commute. But I make sure at least once every couple days I pull it hard up a long hill or wind it out getting on the highway where it can stay wot for awhile.

For the last couple years, after it’s been on a drive, shut down for a short period of time, anywhere from minutes to an hour or three, it sometimes starts funny. Like it doesn’t crank the normal length of time (shorter) it fires and stumbles a bit, idles low, then clears up. Never had a check engine light. I’ve never scanned it to see if anything is pending and never watched any kind of data. It’s just finally getting bad enough now that I’m going to look into it (maybe). Yesterday after it sat about 3 hours it started like this again but actually stalled. Second start was perfectly fine.

I suspect a leaking injector, but I’m not overly familiar with direct injection and not familiar with Mazda at all as far as their issues.

I suppose it could be dirty valves somehow absorbing the fuel, but I feel like that’s a little more far fetched.

Any experience or knowledge of any common issues with these engines? And this hard re-starting issue? Or if someone is curious and nice enough to explore Identifix, I’d imagine someone has posted about this on one of the same engines throughout the Mazda models.

What about cold start ? Was it the same as what you encounter ?

 

[t1snwrbrdr12]

What about cold start ? Was it the same as what you encounter ?

Cold start is perfectly fine. I haven’t done anything to attempt to make this better. It’s a once in a blue moon type of thing and almost seems like an only extremely heat soaked thing, like summer time heat, ac running, underhood temps high type of thing.