RPM fluctuating at idle and AC not cold - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

jamestemperante · 04-27-2022, 06:02 AM

hello again! hope everyone is doing fine. just want to ask your opinion on this matter. I'm on a red light then suddenly, my AC went out and rpm starting fluctuating. Although, car is fine now, all I did was turn of the AC for a few seconds and then all of a sudden, rpm back to normal at idle and AC went back.
Any idea what went down? thanks!

here is a clip of the rpm fluctuating.

https://youtube.com/shorts/cyWBvdzGuh0?feature=share

tomm.brz · 04-27-2022, 06:51 AM

since the very lack of infos about your car, like which year it is or which tune, mods etc, you re getting a generic response as well: it s normal

jamestemperante · 04-27-2022, 07:40 AM

It has a custom ecutek tune. 2013 model NA. it has a blitz intake, agency power headers, nvidia q300. nothing fancy.

tomm.brz · 04-27-2022, 07:52 AM

Then if you have a custom tune best is to ask to your tuner, or post here a log of your car idling and fluctuating
if tuner kept same idle settings as stock then it s quite normal to be not so steady when AC turns on and off

Bonburner · 04-28-2022, 05:38 AM

Try cleaning out your throttle body, no idea if this actually works tbh - some people claim it fixed the problem in the comments.

I've experienced similar behavior .. but mine was due to spark plugs, coil packs, and battery due for a change.
But perhaps I should consider cleaning out the throttle body too ..

jamestemperante · 04-28-2022, 08:56 AM

I haven't change the coil packs, ignition coils but already cleaned my throttle body, changed the spark plugs and battery 2 months ago.

jamestemperante · 04-28-2022, 08:59 AM

idk what went wrong. but the car runs fine now. no rpm dips during idle, only when coming to a stop and AC is on.

Compelica · 04-28-2022, 10:23 AM

In my experience, internally the ECU needs to learn idling and that can take a lot of driving to get it settled so that could be your cause. However there's no indication on when it has fully learned apart from monitoring the Deposit Loss Flow PID.

Bonburner · 04-28-2022, 04:45 PM

Quote:

Originally Posted by jamestemperante

idk what went wrong. but the car runs fine now. no rpm dips during idle, only when coming to a stop and AC is on.

maybe fuel quality or coil packs then

also consider cleaning your MAF sensor

jamestemperante · 04-30-2022, 01:29 PM

rpm drops only when coming to a stop and AC is on. When I'm on a standstill, it doesn't drop.

jamestemperante · 05-02-2022, 04:30 AM

Caught a video of the actual rpm dropping when AC is on.

https://youtube.com/shorts/rXoW_7jf6Wc - AC compressor turning on and off and rpm fluctuating

https://youtube.com/shorts/gWtegwzUUaA - high side of compressor

tomm.brz · 05-02-2022, 09:37 AM

... can you post a log of the car doing this ?

04-27-2022, 06:02 AM	#1
jamestemperante Member Join Date: Oct 2021 Drives: Subaru BRZ Location: Philippines Posts: 47 Thanks: 67 Thanked 9 Times in 7 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	RPM fluctuating at idle and AC not cold hello again! hope everyone is doing fine. just want to ask your opinion on this matter. I'm on a red light then suddenly, my AC went out and rpm starting fluctuating. Although, car is fine now, all I did was turn of the AC for a few seconds and then all of a sudden, rpm back to normal at idle and AC went back. Any idea what went down? thanks! here is a clip of the rpm fluctuating. https://youtube.com/shorts/cyWBvdzGuh0?feature=share

04-28-2022, 10:23 AM	#8
Compelica Senior Member Join Date: Apr 2019 Drives: 86 GT Location: Malaysia Posts: 358 Thanks: 224 Thanked 205 Times in 105 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	In my experience, internally the ECU needs to learn idling and that can take a lot of driving to get it settled so that could be your cause. However there's no indication on when it has fully learned apart from monitoring the Deposit Loss Flow PID. __________________ DIY stuff at Compelica Works

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04-27-2022, 06:51 AM	#2
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,204 Thanks: 502 Thanked 1,070 Times in 778 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	since the very lack of infos about your car, like which year it is or which tune, mods etc, you re getting a generic response as well: it s normal

04-27-2022, 07:40 AM	#3
jamestemperante Member Join Date: Oct 2021 Drives: Subaru BRZ Location: Philippines Posts: 47 Thanks: 67 Thanked 9 Times in 7 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	It has a custom ecutek tune. 2013 model NA. it has a blitz intake, agency power headers, nvidia q300. nothing fancy.

04-27-2022, 07:52 AM	#4
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,204 Thanks: 502 Thanked 1,070 Times in 778 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	Then if you have a custom tune best is to ask to your tuner, or post here a log of your car idling and fluctuating if tuner kept same idle settings as stock then it s quite normal to be not so steady when AC turns on and off

04-28-2022, 08:56 AM	#6
jamestemperante Member Join Date: Oct 2021 Drives: Subaru BRZ Location: Philippines Posts: 47 Thanks: 67 Thanked 9 Times in 7 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	I haven't change the coil packs, ignition coils but already cleaned my throttle body, changed the spark plugs and battery 2 months ago.

04-28-2022, 08:59 AM	#7
jamestemperante Member Join Date: Oct 2021 Drives: Subaru BRZ Location: Philippines Posts: 47 Thanks: 67 Thanked 9 Times in 7 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	idk what went wrong. but the car runs fine now. no rpm dips during idle, only when coming to a stop and AC is on.

04-30-2022, 01:29 PM	#10
jamestemperante Member Join Date: Oct 2021 Drives: Subaru BRZ Location: Philippines Posts: 47 Thanks: 67 Thanked 9 Times in 7 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	rpm drops only when coming to a stop and AC is on. When I'm on a standstill, it doesn't drop.

05-02-2022, 04:30 AM	#11
jamestemperante Member Join Date: Oct 2021 Drives: Subaru BRZ Location: Philippines Posts: 47 Thanks: 67 Thanked 9 Times in 7 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Caught a video of the actual rpm dropping when AC is on. https://youtube.com/shorts/rXoW_7jf6Wc - AC compressor turning on and off and rpm fluctuating https://youtube.com/shorts/gWtegwzUUaA - high side of compressor

05-02-2022, 09:37 AM	#12
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,204 Thanks: 502 Thanked 1,070 Times in 778 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	... can you post a log of the car doing this ?

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