Toyota Yaris Forums - Ultimate Yaris Enthusiast Site
 

 


 
Go Back   Toyota Yaris Forums - Ultimate Yaris Enthusiast Site > Technical Forums > DIY / Maintenance / Service
  The Tire Rack

Reply
 
Thread Tools Display Modes
Old 08-03-2015, 04:02 PM   #1
unadilla66
 
Drives: '07 Yaris 3d, '12 Yaris 3d
Join Date: Jun 2015
Location: ny
Posts: 29
throttle-body, and off-idle question

'07 manual HB, 105k. The car is relatively new to me, so I cleaned the throttle-body and MAS, hoping to cure a slightly erratic idle. With no throttle, should the butterfly be completely closed? It was just slightly open- I could push it closed with my finger to seat against the lip, but it seemed like there was a spring or something holding it slightly open. Normal? Anyway, the cleaning didn't do much with the erratic idle, but it seems to be idling slightly higher now....

Maybe related, maybe not- I find the car does an annoying kind of rpm hunting when driving with just a slight throttle, for example when going down a long medium grade hill on the highway where its not steep enough to just take my foot off the gas, but I'm giving it very little throttle. Its like the computer keeps going back and forth between providing gas and not providing gas. Hard to explain, but I find it annoying (though my wife says she doesn't notice it...). Throttle position sensor issue?
unadilla66 is offline   Reply With Quote
Old 08-04-2015, 02:58 PM   #2
shepd
 
Drives: 2007 Yaris 5 door RS
Join Date: Nov 2014
Location: Kitchener, ON
Posts: 178
The butterfly should not be completely closed unless there's already a notch in it to allow air through (this is what I've normally seen, though I think in the Yaris there's no notch). If it were to close completely, the engine would have no air, and thus would stop.
shepd is offline   Reply With Quote
Old 08-04-2015, 10:04 PM   #3
why?
Only Happy When it Rains
 
why?'s Avatar
 
Drives: Yaris LB
Join Date: Jan 2006
Location: harnett county NC
Posts: 4,097
That sounds normal. The car probably hunts from 600 rpm or a little lower which can cause it to shudder and almost seem to stall up to about 800 or 900 rpm. All the Yari do that because Toyota programmed the car for max gas mileage. You can change that if it really bothers you but there is no real reason to.
__________________
Colin Chapman disciple
why? is offline   Reply With Quote
Old 08-05-2015, 02:19 PM   #4
unadilla66
 
Drives: '07 Yaris 3d, '12 Yaris 3d
Join Date: Jun 2015
Location: ny
Posts: 29
found this in another thread-

Quote:
Originally Posted by Yaris Hilton View Post
When I'm cruising on level ground at around 20 MPH, I often find that the slight amount of power needed to maintain the speed is so close to idle power that it cuts in and out of DFCO, causing a surging effect. When the fuel cuts completely off in DFCO, the car suddenly starts gently decelerating, and on giving it slightly more gas, the power abruptly cuts back on and it surges ahead. It is normal. There's no gradual fadeout from idle power to DFCO, which is negative idle power. It abruptly switches states. It's a minor nuisance. Can't be "fixed." It will be more exaggerated if you push the pedal harder when the DFCO cuts in than if you barely ease it on, as the engine will suddenly start producing power with the throttle wider open.
Seems to explain the off-idle annoyance I was describing. Guess I just need to learn to live with it.
unadilla66 is offline   Reply With Quote
Old 08-06-2015, 10:58 AM   #5
esse10
 
Drives: 2009 yaris 2 door
Join Date: Feb 2013
Location: richmond TX.
Posts: 232
erratic idle

Found something interesting the other day. My car was also having erratic up and down idle issues and low rpm. Problem seems to have gone away ever since I tightened up the serpentine belt. I figured since these cars don't have the belt auto adjust pulley it'll develop this problem from time to time.
hope this helps ya out or other folks out there having the same idle issues.
esse10 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:20 AM.




YarisWorld
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.