RPM fluctuation.....

[Tcoat]

Originally Posted by GotBRZ1691

Did it again this morning. I think the noise im hearing is just the engine bogging down and wanting to stall. Is 600rpm to low of an idle? I want to say yes but am not sure.

I took another video. I have a new laptop so ill download a video editing app so i can post a quick vid here. Will be going to the dealership at some point today

No 600 is just about right. Mine drops to 600 after warm up and sits there as steady as a rock. Now it does do a slightly progressive drop from the 2000 rpm fast idle to about 1000 then 600 so if this is what you are seeing then it is normal. If it is dropping much below 600 you may have an issue though.

[Sigh-on-Rice]

Originally Posted by GotBRZ1691

Is 600rpm to low of an idle?

Mine idles at 600 rpm when the A/C is off. When the A/C is on, it idles at 700 or so, but sometimes it drops to 500 rpm and the engine would bog a little. This only happens like once a month, so I never took it in to get it checked out. Once it starts doing this, it keeps doing it until I turn off the engine once. Then it won't happen for another month or so. Mine is 2013 MT btw.

[Trap63]

Originally Posted by Tcoat

No 600 is just about right. Mine drops to 600 after warm up and sits there as steady as a rock. Now it does do a slightly progressive drop from the 2000 rpm fast idle to about 1000 then 600 so if this is what you are seeing then it is normal. If it is dropping much below 600 you may have an issue though.

So , I explain what happens in Italy to understand how fuel quality and RON may involve idle trouble.
In Italy BRZ is sold with warning for fuel refill ONLY for RON 98 Minimum or Higher. RON100 means 88 MON or 94 AKI (CAN/US).
It' very difficult to find RON98/RON100 in Italy, besides it's usual to find RON95 (below the Ron ratio suggested by Subaru).
in certain self-adaptive management of ECU , fuel under ratio or with poor quality might involve the engine in idle trouble with some inconsistency around 738 rpm (standard lower limit).
Up to BRZ MY2014, Subaru Italy (Europe) assistance network upgrade the rom with @02G release coming from Australian release that solved in past this issue.
Since MY2015 (late 2014), some engine parts are changed (valve, spring) for new directions coming from emissions regulator (Euro6). More restrictive emissions rules with poor fuel ratio or poor fuel may produce this issue.
Try to refill with proper ratio (US ratio) at least twice, run (travel) and verify if trouble/issue is.
When properly refiling (in Europe) in MY2015 this issue will disappear. Might be the same for US model.
Adding to this noise, in past (2015, early) Ecutek found a special function item in subaru's software that check in real time the efficiency of 2nd catalyst bank (U1402 engine warn, hoping to well remember the digits) even if the setting is OFF, pretty deep inside the release . Running check of efficiency might involve some issue in idle.
Ecutek modified this feature in June both for dekat and non-dekat exhaust line to avoid constant check of it.

[nikitopo]

Originally Posted by Trap63

Since MY2015 (late 2014), some engine parts are changed (valve, spring) for new directions coming from emissions regulator (Euro6).

I think the change to Euro6 happened in the MY2016 models (after July 2015). I have the latest brochure that says Euro6, but last year's models had the Euro5 specification.

[steve99]

Originally Posted by Trap63

So , I explain what happens in Italy to understand how fuel quality and RON may involve idle trouble.
In Italy BRZ is sold with warning for fuel refill ONLY for RON 98 Minimum or Higher. RON100 means 88 MON or 94 AKI (CAN/US).
It' very difficult to find RON98/RON100 in Italy, besides it's usual to find RON95 (below the Ron ratio suggested by Subaru).
in certain self-adaptive management of ECU , fuel under ratio or with poor quality might involve the engine in idle trouble with some inconsistency around 738 rpm (standard lower limit).
Up to BRZ MY2014, Subaru Italy (Europe) assistance network upgrade the rom with @02G release coming from Australian release that solved in past this issue.
Since MY2015 (late 2014), some engine parts are changed (valve, spring) for new directions coming from emissions regulator (Euro6). More restrictive emissions rules with poor fuel ratio or poor fuel may produce this issue.
Try to refill with proper ratio (US ratio) at least twice, run (travel) and verify if trouble/issue is.
When properly refiling (in Europe) in MY2015 this issue will disappear. Might be the same for US model.
Adding to this noise, in past (2015, early) Ecutek found a special function item in subaru's software that check in real time the efficiency of 2nd catalyst bank (U1402 engine warn, hoping to well remember the digits) even if the setting is OFF, pretty deep inside the release . Running check of efficiency might involve some issue in idle.
Ecutek modified this feature in June both for dekat and non-dekat exhaust line to avoid constant check of it.

Originally Posted by nikitopo

I think the change to Euro6 happened in the MY2016 models (after July 2015). I have the latest brochure that says Euro6, but last year's models had the Euro5 specification.

I have had a look at the latest euro/australian roms ZA1JF01G and compared to earlier roms like 700G or A01G A02G and all the fueling ignition timing , intake/exhaust valve timing tables are same.

Only a few minor changes to atmospheric pressure compensations and other very minor compensation tables. so look like nothing changed engine tune wise.

A02G they seem to have altered things in the idle control area, I tried that rom but still got the odd idle dip comming to stop with A/C running.

Fixed this by making the ecu run full Direct injection at idle instead of a di/pi mix of 30%

change all three di/pi ratio tables as below, ie set the 02 and 0.3 load colums to zero to run full DI

You can also bump all your idle tables minimum value to 700 rpm instead of 650




for better knock resistance on lower quality fuel you can also change the axis value in the bottom left corner from 5200 to 7200 then the 20% port wont cut back in till 7200 see below.

My South africian friend said this allowed them to add back in about 3 degrees on timing at higher rpm , they only have 95 ron fuel. On good fuels this tweak makes no difference at higher rpm





The only codes I have ever had to disable for catless header is P0420 cat efficiency.

and if you disable the high rev cold start and reduce the post start ignition timing to quieten it down on USA roms you will throw code P050B (post start ignition timing just disable it.

On Euro/Australian roms you dont throw P050B, appears its not monitored in non usa roms.

[steve99]

Originally Posted by GotBRZ1691

So i noticed that my BRZ has just started doing this. I started the car in the drive and let it come up to temp. Once the rpms dropped to idle, i noticed it was idle hunting continuously, from 600rpm to 900rpm. Additionally, I hear a rattle when apply slight throttle to bring the car up 200/300 rpms, from 600rpm.

Is this rattle potentially because the car wants to stall? Or should I get it looked at.

Im going to post a video this afternoon as I think my engine is more clicky and rattley, but that may just been paranoia getting to me.

Current mods include K&N intake, Perrin Cat back, Perrin LWCP, Stock tune.

Current mods include K&N intake, Perrin Cat back, Perrin LWCP, Stock tune.

your idle issues are likely exaggerated due installation of non-standard intake and still running stock tune, likely MAF scaling
issues.

The maf sensor is moved close to throttle body with K&N intake likely resulting in turbulance or weird maf readings at low rpm, not sure in K&N intake has air straighter before MAF sensor like stock and Grimspeed intakes have to reduce this

[Benedict]

Hey everyone, first post.
I originally drove a 2014 FR-S with 100k miles. the fluctuations were pretty bad, close to stalling pretty often. Never really saw it as a problem, when you're driving it doesn't fluctuate and its a common problem. Now I drive a 2019 BRZ. incredibly, the car is built like a 2014. the fluctuations aren't that bad anymore, I can't think of any times I almost idled, but I've only driven 2500 miles. Not only that, but the recalled high pressure fuel pump chirping is also very audible from anywhere in or around the car.
forum for HPFP - https://www.ft86club.com/forums/show....php?p=2870281

My vin is outside the effected range so dealership won't even look at it, car is out of warranty because of accident with previous owner.

after tune the idle sits around 800. It doesn't dip very much.

[radroach]

@Benedict you mean you'd have idle RPM's dip at idle, which might cause the engine to almost stumble? Pretty common thing on the earlier cars. I sometimes get a slight idle dip when turning on my lights, clicking the window up/down switch, or turning on the A/C. It's just the accessories (alternator, A/C) putting load on the engine and the engine needing to catch up and compensate.

The later model cars had a more intelligent charging system that prefers to load the alternator and charge the battery when you're moving, would make sense that you experience less of these problems.

Other than that, if you keep your battery in good shape, I think you'll get fewer stumbles on the earlier cars.

[Benedict]

Originally Posted by radroach

@Benedict you mean you'd have idle RPM's dip at idle, which might cause the engine to almost stumble? Pretty common thing on the earlier cars. I sometimes get a slight idle dip when turning on my lights, clicking the window up/down switch, or turning on the A/C. It's just the accessories (alternator, A/C) putting load on the engine and the engine needing to catch up and compensate.

The later model cars had a more intelligent charging system that prefers to load the alternator and charge the battery when you're moving, would make sense that you experience less of these problems.

Other than that, if you keep your battery in good shape, I think you'll get fewer stumbles on the earlier cars.

its weird because the battery was replaced but on the meter you can see it fluctuate between 14 V and 10 V. It's not really a problem, the car runs great and I love it. Just a little odd

[radroach]

@Benedict volts, not watts