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- Oct 27, 2015
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- 2017 Cosmic Blue EX-L Sedan
- Vehicle Showcase
At least in my case, the low idle once warm happened since day 1. I'd have a smooth idle at all the stoplights going to work until my last one exiting the highway, 10 miles into the drive. I'd be stopped and would see my passenger seat vibrating. And rpms would hover around 600. The reason I never took it to the dealer was the many members here saying their CVT turbos experienced the same scenario. And the dealer's they went to saying were all saying "normal".It would be interesting to know whether the service manual ever had any revisions regarding the idle speed.
I'm slightly unsettled by the service saying it's normal, while it's out of the specified range. Unless they are saying "it will go out of spec as the engine gets older and nothing can be done about it."
Which doesn't mean they are not right. As the piston rings etc. get slightly worn, the engine internal friction decreases and the reduced idle load might cause the ECU to allow the rpm to drop, until a slight external load or a tuning fix compensates for it.
I know you are saying that idle speed is out of spec according to the Honda service manual. A couple points/questions...
1. Was the service manual for 2016 and 2017 models?
2. You mentioned that those idle numbers were in neutral.
I've noticed that the warm low idle and shaking would lessen/stop when doing two things. Turning on the climate control or putting the transmission in park or neutral. Maybe those high neutral numbers in the service manual are lowered when the transmission is actually engaged?It specifies the idle speed in neutral as:
670 to 770 rpm for 1.5T
Here's the other interesting comparison. Right now I run a TSP Stage 1 tune. My car idles very smoothly because Derek has warm idle set at around 700-730. When I've had my car back to stock from time to time, that shaky, rough warm idle hovering a bit above 600 rpm comes back.
Last but not least. All the folks complaining about the low idle seem to own CVTs not manuals. And here's my theory which may be totally wrong...
Idle is higher in neutral than when in gear. And obviously manual trans. owners are putting their cars in neutral at stoplights. The CVT drivers of course are leaving it in gear where it seems to idle slower. Again it seems like this issue only happens on the earlier model years. I never hear about it on 2019's or 2020's which suggests Honda changed something. Maybe that something was the factory dilution "fix".