01-13-2020, 07:20 PM
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#16
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Join Date: Oct 2014
Location: Citrus Heights, California
Age: 36
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Real Name: Jerod
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Elite Member
Join Date: Oct 2014
Location: Citrus Heights, California
Age: 36
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I'm going to throw a wrench in the cogs here.
I have an over-bored throttle body with a custom butterfly valve (brass plate) that is seamless with the body housing. There is no gap between the valve and the housing since it's CNC machined to tight tolerances. On top of that, I have some non-air assist injectors with large o-rings that appear to completely block the air-assist holes that are in the intake manifold. My 4Runner idles fine (except when the engine gets hot & idles for 5 min or so then it stumbles a little down to 550 RPMs).
So that means my valve is airtight as can be and there's no airflow from the throttle body to the injectors. My idle is the same from when before I modded all that so theoretically if you follow the logic my engine should stall, but it doesn't. Although my IAC is clean and does operate, maybe that's the part that fails when dirty and affects idle & stalling. I have a 98 though.
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01-13-2020, 07:42 PM
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#17
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Join Date: Mar 2016
Location: Pasadena, CA
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Quote:
Originally Posted by gamefreakgc
Although my IAC is clean and does operate, maybe that's the part that fails when dirty and affects idle & stalling. I have a 98 though.
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The '96-'00 throttle bodies should close completely when the throttle is released (there is some spec in the FSM, I'm sure). The IAC should supply sufficient air for idling the engine.
The amount of air that passes through the air assist injectors must be fairly small...
-Charlie
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'99 4Runner SR5 Auto - 4WD swapped
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01-13-2020, 10:44 PM
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#18
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Join Date: Aug 2019
Location: Iowa Colony
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Location: Iowa Colony
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Quote:
Originally Posted by phattyduck
The '96-'00 throttle bodies should close completely when the throttle is released (there is some spec in the FSM, I'm sure). The IAC should supply sufficient air for idling the engine.
The amount of air that passes through the air assist injectors must be fairly small...
-Charlie
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It's supposed to be open just slightly. I can't remember if it's a percentage or a physical distance. I remember looking through mine during my swap process and you could see the light coming through the edge of plate.
Otherwise your engine gets no air and stalls completely but you know that lol I think you were just being short with words, but for others who may derail it, it is supposed to be open a small smalllllll amount
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01-14-2020, 01:38 AM
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#19
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Join Date: Feb 2015
Location: San Jose, California
Age: 58
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Real Name: Tim
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Quote:
Originally Posted by STI_MECE
It's supposed to be open just slightly. I can't remember if it's a percentage or a physical distance. I remember looking through mine during my swap process and you could see the light coming through the edge of plate.
Otherwise your engine gets no air and stalls completely but you know that lol I think you were just being short with words, but for others who may derail it, it is supposed to be open a small smalllllll amount
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It depends what throttle body you're talking about. The 96-00 throttle plate closes all the way. Yes, there might be tiny slivers of space on the sides you can see light coming through but that's not where the engine is truly getting the air it needs when idling. The IAC valve is providing the engine the air it needs.
Now, if you're talking about the 01 and 02 throttle bodies, those throttle plates don't close all the way because the engine is using the air traveling through the throttle body bore to keep the engine running.
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01-14-2020, 01:19 PM
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#20
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Join Date: Nov 2014
Location: Marietta, Georgia
Posts: 1,500
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Quote:
Originally Posted by mtbtim
Another thing I'm wondering about now with this 01 and 02 throttle body is could you throw off the calibration of the throttle plate since it's partially a DBW system? I remember watching a video about cleaning a throttle body and IAC and the guy mentioned he didn't think it would be smart to manually move the throttle place on a fully electronic throttle body because it could mess up the calibration. I'm just trying to understand why some guys have had a high idle after cleaning this newer style throttle body.
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I went back & forth for a little while about the best way to clean my throttle body because of the same info you mentioned. I ended up cleaning it the same way as it would be done on 96-00 by manually moving the throttle plate. I still don't have confirmation if this is correct or not but haven't noticed any issues for the last 80k. Been doing it this way everytime I clean the MAF and change the spark plugs. The only time I've seen a temporary high idle was after cleaning the throttle body on my friends 99 but it resolved after several minutes.
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01-22-2020, 03:39 AM
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#21
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Join Date: May 2019
Posts: 138
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Not sure if it helps at all, but I posted a bit of a tear down of my old TB on my 2002 in this thread:
The Exclusive 22030-62020 Club! Throttle Body Tear Down.
It has pics of the innards.
If you clean the TB, just take that little metal plate off and clean inside too (see pictures in that thread). Either way, there isn't much you can mess up...but you do need to get those little airways open.
Also, I measured the resistances on the brandy new TB. The Pedal Position Sensor on the new one was fairly close to the old one, for both closed and open.
The TPS side...has some obvious issues. Numbers were whacked on the old one compared to the new one. I want to recheck my measurements before posting.
-Mike
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Last edited by negusm; 01-22-2020 at 03:42 AM.
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12-21-2020, 11:23 PM
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#22
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Junior Member
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Join Date: Jul 2020
Location: Orlando, FL
Posts: 2
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Location: Orlando, FL
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Hi guys,
I hope this posts find you. I cleaned the throttle body on 20024runner SR5 , and now I am getting P0304 Cylinder 4 misfiring, idle RPM low, car vibrate while driving Could it be due to those 6 holes getting clogged up, and should I open the small compartment above the 6 holes and clean them out? Also, I just reused the same metal gasket, could it be due to gasket there?
I appreciate if someone can guide me to get over this.
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12-22-2020, 10:40 AM
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#23
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Join Date: Sep 2011
Location: Austin, Texas
Posts: 3,145
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Quote:
Originally Posted by ahoss4Runner2002
...I just reused the same metal gasket, could it be due to gasket there?
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Isn't the metal gasket a crush type? I believe so, a new one is needed.
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2001 Limited 4WD - 346+K - SunfireRed\Thunder Cloud; - 265/75/16 Michelin A/T2s - Fat Pat's 1.5" BL - StopTech ANGLED rotors - In series 699 trans cooler, New Yota1 transmission, All new OEM suspension front to rear.
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12-22-2020, 10:56 AM
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#24
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Join Date: Jun 2016
Location: MS
Posts: 2,488
Real Name: Mark
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Join Date: Jun 2016
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Quote:
Originally Posted by ahoss4Runner2002
Hi guys, reused the same metal gasket, could it be due to gasket there?...
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FSM indicates one time use TB gasket, reusing a crap shoot, has been done though.
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