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Toyota RAV4 Throttle Lag

79 messages,  Last post on Aug 11, 2009 at 7:38 PM

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#51 of 79 Re: throttle lag clue? [fordm] by wwest Oct 31, 2006 (12:46 pm)
Replying to: fordm (Oct 27, 2006 8:17 am) Sure...!   Higher octane allows the engine to operate in a Taller gear ratio at a low(er) RPM without "lugging", knock/ping.   So with a higher octane when you initially re-apply pressure to the gas pedal shortly after/during the lift-throttle upshift the transaxle may (more often) remain, briefly, in the "taller" gear ratio since the ECU "knows" that will not result in a seriously detrimental level of Knock/Ping. The ECU would therefore allow the DBW system to immediately begin raising engine RPM, generating additional drive torque, as a result of the new, re-applied, gas pedal pressure.   So now the engine RPM is no longer at idle and should you continue to increase the pressure on the gas pedal such that a downshift is required to keep the engine in a proper, non-lugging, operating range there is now much more likelihood that there will be be enough ATF pump pressure/flow volume to accommodate the upcoming downshift.   The above might also be an indication that a fairly s..l...o....w re-application of pressure to the gas pedal after a FULL lift-throttle event might often alleviate the downshift delay/hesitation regardless of octane. Whereas a quick/fast/heavy re-application would almost always result in a serious level of knock/ping absent an immediate downshift.   Counter-intuitive, huh..??   Go SLOW, to GO QUICKLY...!!   Okay...??
#52 of 79 NHTSA...investigations. by wwest Oct 31, 2006 (12:55 pm)
Regardless of lack of mental capability of the idiot on the US throne at the moment our government is not altogether stupid.   Bear with me for a moment and just briefly assume that my theory is correct that these 1999 to current MY transaxle problems have arisen out of the need to alleviate the potential for engine compression braking interferring with the anti-lock braking system.   If that is the case and an investigation were to be opened the obvious conclusion would be, must be, that absent these new transaxle charactoristics all FWD or front torque biased AWD vehicles are inherently unsafe for operating on adverse, slippery, roadbed conditions.   So were I the head of the NHTSA I wouldn't dare even open an investigation once Toyota informed me of the base purpose, cause, of these symptoms. Replies to this message: steve_ (Oct 31, 2006 12:57 pm) wwest (Oct 31, 2006 1:43 pm) steve_ (Oct 31, 2006 7:12 pm)
#53 of 79 Re: NHTSA...investigations. [wwest] by steve_ HOST Oct 31, 2006 (12:57 pm)
Replying to: wwest (Oct 31, 2006 12:55 pm) I've already voted and am hoping to avoid further political commentary for a couple of years so please take that stuff elsewhere.   So, go slow to go fast - now wrap that in with transmission "learning" and tell me how confused the car is going to get? Replies to this message: wwest (Oct 31, 2006 1:43 pm) steve_ (Oct 31, 2006 7:12 pm)
#54 of 79 Re: NHTSA...investigations. [steve_] by wwest Oct 31, 2006 (1:43 pm)
Replying to: steve_ (Oct 31, 2006 12:57 pm) Personally I don't buy into that individual driver uniqueness learning bit whatsoever!   Granted, these ECU's do have to "learn" the charactoristics of the individual sensors and in some cases deterministic forcing functions due to unavoidable tolerances. But I do not believe that any significant level of driver unique charactoristics "learning" is involved in the majority of these "driveability" complaints.   Yes, most of these systems "watch" driver functions and according to the engineering white papers I have read will categorize each driver into one of four "bins" within a few seconds of first putting the vehicle in motion, and then with more time will refine the characterization into one of sixteen "bins".   But all of the learning regarding individual driver unique charactoristics is ERASED each and every time the engine is (re)started. Replies to this message: steve_ (Oct 31, 2006 7:12 pm)
#55 of 79 Re: NHTSA...investigations. [wwest] by steve_ HOST Oct 31, 2006 (7:12 pm)
Replying to: wwest (Oct 31, 2006 1:43 pm) Some cars do offer "sport" and "economy" modes - guess the next marketing push will be "16 bin selections" on the 2009 Smurfmobile.
#56 of 79 SNOW mode...! by wwest Feb 02, 2007 (1:27 pm)
Assuming the new shift pattern upshift technique is to help alleviate accidents due to loss of directional control arising for engine braking, why not just have a SNOW mode that can be activated by the driver, by a rain sensor, or if the OAT hovers around or below freezing.   Upon a full lift-throttle event in SNOW mode the transaxle would remain in the same gear ratio but the engine RPM, via DBW, would not be allowed to fall enough to provide a significant level of engine braking to the driven wheels, front, rear, or ALL.   Absent being in SNOW mode the shift patetrn could be the same as it was pre-2000.
#57 of 79 Re: throttle lag [raviola4] by edr5 Sep 28, 2007 (5:50 pm)
Replying to: raviola4 (Oct 06, 2006 8:47 am) I have experienced the same throttle lag. Even worse, I pulled into a left turn lane, came to a stop briefly, nothing was coming, so I pushed the accelerator, the engine rev-ed - and the car did not accelerate at all! I pushed down a little more expecting it to kick in - and nothing but engine rev! So I took my foot off the gas completely and after about 10 seconds tried again and it went. I took it to the dealer - they said this was "normal." I repeated this back to the service manager and when you say it out loud "I push the accelerator and the car does not move," then it does not sound so "normal." They apparently did read this forum after I told them this was not the first RAV this has happened to. But they could not "recreate" the problem so they did nothing. The guy did admit that they can now re-flash Camry's with throttle lag, but they are not allowed to do that to RAV's.   Now the stereo is going haywire. Sometimes it does not respond to the on/off button, and sometimes the display will not come on even though the controls work. Is there some kind of electronic problem that would affect both throttle control and the stereo? Seems unlikely but am curious. Replies to this message: user777 (Sep 29, 2007 1:21 am) cbmorton (Sep 29, 2007 12:42 pm)
#58 of 79 Re: throttle lag [edr5] by user777 Sep 29, 2007 (1:21 am)
Replying to: edr5 (Sep 28, 2007 5:50 pm) edr5, i'm sorry that your dealership is giving you the run-around.   i've cited your post as a good application of a obd-ii reader and laptop to capture the very unsafe and non-normal operational behavior of your toyota vehicle - which your dealer is claiming is normal and won't do anything because (supposidly) they cannot re-create, they are not motivated to re-create, or re-creating will put them in a difficult situation.   look here: user777, "2007 Toyota Camry Problems and Repairs" #4055, 29 Sep 2007 2:12 am   w.r.t. your stereo: here's what may be happening: do you use the on/off control of the radio a lot? if so, it's possible carbon build-up from many uses (everytime you press on, a tiny spark is generated at the switch contacts causing arcing and oxidation) is causing the switch to fail to close the circuit to power up the unit because of accumulation. it's possible specialized electrical cleaner could be used on the switch if the radio was removed, but you'd best have that theory passed by someone.   the radio display not working... sounds like it might be a loose connection to the radio or in the radio itself. sorry, i don't know more about the stereo in your vehicle.
#59 of 79 Re: throttle lag [edr5] by cbmorton Sep 29, 2007 (12:42 pm)
Replying to: edr5 (Sep 28, 2007 5:50 pm) Dealers will replace bad radios under a Toyota TSB that has been out since earlier this year. Had mine done in the spring after it started either going blank or displaying Japanese characters. The problem has not returned.
#60 of 79 Re: throttle lag clue? [fordm] by dsteinhorn Jan 25, 2008 (7:25 am)
Replying to: fordm (Oct 27, 2006 8:17 am) I have had the same problem on a 2004 and brought it to the dealer's attention mutliple times without resolution. Fall 2007, I was told it needed a throttle body flush and had that done for $125 by the local dealer in Chicago (Grossinger). Today I took it in for an oil change and was told it needed another throttle body flush for another $125 and, by the way, did the throttle seem to stick...... When I challenged the service manager to justify needing another $125 throttle flush in just 4 months, he told me he makes recommendations based on what he sees. Watch out for these vultures. You never know what the real truth is.........

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