wwest

The ash plume is currently headed NE toward Yakima, but we are keeping a careful eye. The 01 Porsche is still in Memphis where we left it after Daytona. Plan to go back in May, nicer weather on the Northern route, and drive it home. But thanks for thinking of us. Redmond, WA

The 90 through 93 LS400 had a poor headlamp reflector forward coverage design. If you adjust the low beams upward for good low beam coverage then the high beam pattern will be, is, far too high. Adding brighter bulbs will NOT help. The best solution is to adjust the high beams for correct forward coverage and then add two driving lights in the lower portion of the grill to fill in the poor low beam coverage.

Anything that "softens" the blow in an accident will affect the trigger level of the airbag system.

Low line pressure...error code. I'm sure there would be if they had a feedback sensor to measure line pressure with, or some derivative method.

Okay, here is my FINAL answer. The absolutely correct one. Modern day cars are shipped from the factory with only rudimentary "tutoring". All of the engine fuel mixture and performance parameters are loaded into their respective ECU (ROM?) memory tables as preliminary approximations. For instance, my 1993 Ford Ranger with an I4 has an idle air bypass solenoid that is used to provide a linear function. As time goes by the engine ECU "learns" how to correctly pulse width modulate the idle bypass solenoid so that the oxygen sensor in the exhaust path indicates no unburned oxygen. If you disconnect and reconnect the battery to go back to the factory approximation settings the I4 does not pass the WA idle emissions test. Drive it around for two days and the engine ECU "learns", deterministically, what pulse width modulation values to apply to the idle bypass solenoid under the engine various operating parameters, engine temperature, inlet air temperature, and absolute pressure. I would guess that many more modern cars operate in the same way, all the tables and parameters for approximately correct operation are loaded at the factory and those parameters are then continuously updated, for fuel economy, low emissions, and driveability, as you drive. Obviously the battery disconnect/reconnect procedure would cause the system to reload the factory default approximations and then the learning process would begin all over again. So, no question, "reset" the car's ECU's via disconnecting and reconnecting the battery and the drive "feel" of the vehicle will suddenly be different, at least for a few days ormiles. But what about learning individual driver's driving styles?? Within0 seconds of having started the car and put it into motion the engine and/or transmissions ECU(s) will have preliminarily "mapped" your personal driving style. After three minutes the ECU's will have come to a "final" conclusion on where to place you within the various driving style parameters. As many as 10 driving style "modes" seem to be indicated by one of the European marques. Thereafter the ECU's keep a "running" three minute history and if you suddenly become more aggressive or passive it will then remap you into another "style". So the dealer mechanics and technicians statements are correct, resetting the ECUs WILL change the vehicles driving charactoristics, "feel". But with a fairly short period the ECUs will have learned the best parameters for the vehicle's operation.

Look, were I the ONLY one to drive my car then I would certainly tend to believe that disconnecting the battery would remove any memory of my previous driving habits. Additionally I have very little doubt that the various ECU must then "recalibrate" themselves based on actual feedback signals from the various sensors. That sensor recalibration sequence alone can account for a "new" driving "feel" after the battery is reconnected. But everything I can find to read on this subject indicates that the "learning" of an individual driver's "style" begins anew each and every time the engine is restarted.

Were I you I would stay the hell away from Lexus of Bellevue, good sales staff, excellent parts department, but service is PURE ripoff. I have 5 LS400s, 3 92s, a 95, and a 98, within my company, close friends, and family. Had ONE RMS inexplicable failure immediately, discovered the day after, on its return from Lexus of Bellevue. Don't want to implicate Lexus of Bellevue but I later learned that overfilling the crankcase and then running the car that way for awhile will result in a blown RMS. As pure happenstance I stopped having them service my own new 92 because a "gofer" added the Mobil 1 I provided without first draining the old oil. Luckily I have always done a followup check and discovered the overfill the next morning. The 95's EGR tube did fail and I was quoted $1200 for repair but I simply removed the part still attached to the exhaust and sealed it by bending it over tightly. Still passes emissions with flying colors. And we really can't, shouldn't, blame Lexus of Bellevue, or any Lexus dealer, for these tactics. All Lexus cars are extremely reliable and therefore absent scheduled maintenance work (accelerated whenever you can be conned into it)and misc. unneeded addons, the service depart wouldn't have enough work to keep the staff on board that they would need when REAL work comes their way. Needless to say other than the above oil and filter at 7500 miles is all the "feeding" my LSes get.

What if the engine hesitation problem is the result of low transaxle hydraulic pump capacity?? All of the clutches, including the lockup clutch, are actuated by hydraulic pressure via the pump driven with a cam on the input shaft. Suppose that the unusual shifting sequence, QUICK sequence, exhausts the hydraulic pressure just enough that the NEW shift sequence cannot occur absent a few turns of the engine to "rebuild" hydraulic pressure? You're in the acceleration lane, low gear engaged appropriate to acceleration, Lockup disengaged to take advantage of the torque multiplication. Now you get slightly off the gas and briefly enter "cruise" mode. The engine RPM declines to idle, the tranmission upshifts into the most appropriate gear and the lockup clutch is engaged. But now you lift the gas pedal completely and apply the brakes and the lockup clutch must be disengaged. And NOW...you apply the gas sharply because you wish to accelerate. Ooops! Hydraulic pressure was exhausted during your previous efforts and now it will take many turns of the engine, input shaft hydraulic pump cam, to build enough pressure to be certain of the newly required downshift sequence. When Toyota and Lexus decided to use the lockup clutch in the same manner a person would use a REAL clutch did the engineers consider the extra duty, capacity, this would require of the transaxle's hydraulic pump.

Historical data... Yes, lockup clutches have been in use for many years. But only with the advent of FULL electronic control of the shifting has the lockup clutch begun to be used in other than O/D mode. As I understand it, with ECU control the lockup clutch is now engaged anytime the vehicle is in "cruise", no substantial level of engine torque, mode. Disengaged for acceleration, any shifting sequence and/or when coming to a stop wherein the engine would stall if the "solid" coupling were maintained.

"stopping distance is reduced" NOT! Read some of the newer analysis on the subject. Soon, I hope, we will begin to see ABS enabled ONLY if the VSC system indicates that loss of directional is impending.

I'm sorry... But how can anyone of reasonable intelligence believe that the ECU, any ECU, in these cars has a long term memory of someone's driving style? How does it handle the fact that my wife has a completely different driving style than I? What about families with both parents and teenage kids, all as oftentime drivers? What about the rental "fleet". No, if any of these ECU's "learn" on the fly then their memory is WIPED each and every time the vehicle is restarted. Please remember that it was not long ago that the common (FALSE) knowledge gleamed from dealers, salespersons, mechanics and technicians, was the ABS was of benefit in shortening stopping distances. And please keep in mind that should the manufactureers really wish the ECU to learn each individual's driving style then they could most readily provide coded, "personalized" ignition keys for each person who will be driving the car. Many cars, Porsche, Chrysler, etc, already provide individually coded keys for the seat memory and various other "memory" aspects of modern day cars.

The more I learn about this the more scared of the future I get. Just now had a good conversation with a third party automatic transmission technician. He said that earlier lock-up clutches did tend to fail prematurely (the one in my 2001 RX300??) due to the inability of the controlling ECU to have close enough control to prevent clutch slippage on engagement and in some cases even while engaged. According to him the industry has recently changed the clutch design to a carbon fiber frictional surface. Apparently carbon fiber is a lot more tolerant of the high level of slippage incurred in ECU controlled transmissions. He also stated that if the lockup clutch is engaged it will be disengaged for each shifting sequence and then re-engaged once the shift sequence is complete. Don't know if any of this applies to the hesitation issue but I have never found more information to be detrimental. That new BMW X3 w/manual transmission is looking more and more attractive every day.

The referenced document is an authorized copy of an actual Toyota document.

No law.... But a public mindset??

"upgraded power explorers..." etc, etc. None that you have mentioned involved hybrid technology. Seems to me that going to the effort to design a hybrid system and then using it to tout HP is like the farmer saving rain water from the roof and then letting some of it just evaporate away.

Funny.... When I drive my AWD 996 Porsche GT3 I feel quite comfortable with its level of HP/torque but I also find myself with the same level of comfort in my AWD RX300 or even in my 92 LS400. I guess some of us have more adaptive minds than others. Now, my 93 Ford Ranger with 2.3L manual does take some getting used to, adjusting to.

Fan, blower motor, is not enabled in auto mode until the engine water jacket temperature rises to 130F

Confirmation.... You can PREVENT the hesitation symptom by fully releasing the gas pedal during coastdown! The lockup clutch is disabled, cancelled, if the throttle position is at IDL ( idle) or brakes are applied. See page 14 of: http://www.autoshop101.com/forms/h16.pdf Document reprinted by permission of Toyota.

Simpler explanation, maybe. remember, I have NO personal experience except that which I have related regarding my 2001 AWD RX300. But my guess is that the "key" to this whole thing is our/your specific "treatment" of the gas pedal. You accelerate up to 35MPH in the acceleration lane and then you ease off the gas pedal waiting for, or to "match up" with an opening in the traffic flow. If you only ease off, still maintain even a small throttle opening, light pressure on the gas pedal, the system is very likely to switch to "cruise" mode, and engage the torque converter lockup clutch. If, on the other hand, you lift off the gas completely the system will obviously assume a coastdown circumstance and keep the lockup disabled. This theory also lends credence to the left foot braking having some unknown effect that leads left foot brakers to encounter the hesiation symptom more often. I would suspect that when one uses the left foot for braking the right foot may very well "rest" on the gas pedal just lightly enough to keep the throttle slightly open. But back to the original slight pedal pressure theory. You slacked off the gas and the system locked up the torque converter for low torque engine cruise fuel economy. Now you suddenly want some serious acceleration from this beast, not WOT throttle, but an acceleration level that will let you merge safely into that "slot". The secondary purpose of the design of the torque converter is to provide torque multiplication for just this scenerio. Of course you want the torque converter in "play", as does Toyota and Lexus because even with its 10% power loss it provides enough extra torque, 2 times that which is input, that the fuel economy net is a gain. But how do we get that lock up clutch to release quickly? Not only do we wish to use the torque multiplication capability in this instance, but because the lock-up clutch is not designed for high torque applications, it MUST be out of the loop before we allow the engine to build torque. So the ECU releases the power to the lockup clutch control solenoid and that releases, in turn, the hydraulic pressure that was holding the clutch engaged. But since the lockup clutch cannot long survive if it is engaged during high engine torque operations the ECU must be certain of lockup release before advancing the throttle servomotor, opening the throttle in response to the gas pedal position. And if the feedback sensors in the newer models are the same as my 2001 the only method through which the ECU can tell that the lockup clutch has been successfully released is by comparing the torque converter input speed (engine RPM) and the torque converter output speed via its turbine speed sensor. If these two speeds are not equal then the lockup clutch CANNOT be engaged. But what if, strictly by happenstance, the lockup clutch is actually released but there is no torque converter input/output speed difference due to roadspeed and the particular gear ratio currently selected? The engine is slightly above idle, say 1200 RPM, at ~30mph what gear would need to be selected to closely match the engine RPM? If I were the programmer trying to solve the above problem I would likely add in a timer of enough period to assure that in 99.99% of circumstances the lockup clutch had enough time ( 1 second? 2 seconds?) to fully release before allowing the throttle to open. The above theory also explains why my 2001 has burned fluid at 38k miles... The lockup clutch is NOT fully released when the mechanically coupled throttle opens suddenly in exactly the same circumstance as above.

In doing some research on the internet I have found several engineering "white papers" and a few actual manufacturer documents which just might explain the problem. Based on what I have found there can be no question that the manufacturers are using the lockup aspect of the torque converter to extend the fuel economy and thereby very likely reduce overall emissions. Historically the torque converter has been used as a "clutch" to prevent the engine from stalling with the transmission engaged. It is also used as a torque multiplier, as high as a factor of 2, when accelerating. While the torque converter is quite helpful in that multiplication mode it also results in the loss of about 10% of the fuel economy in acceleration mode and even a greater percentage loss when you're just cruising along. So, according to the papers and documents some manufacturers are locking up the torque converter in all gears, even in 1st. Obviously the torque converter cannot be locked up if wheel speed and selected gear ratio is such that the engine might stall. So, you're in that merge lane, you slack off the gas slightly (throttle NOT fully closed) waiting for an "opening", the system says "ah-ha, we're cruising" and slips the transaxle into a cruise gear ratio and the torque converter into lock-up. Now you suddenly ask for acceleration and the lockup must be released (has feedback "loop" closure indicated the previous upshift and lockup "completion"?) and the transaxle must be downshifted into the appropriate gear. Unless Lexus has added another sensor in order to "know" the lockup sequence has completed the engine RPM and the torque converter turbine speed must be equal. The problem, as I see it, is that these inputs can also be "equal" at times, strictly by happenstance, with the lockup disabled. So, you re-apply that gas pedal to accelerate, the engine is "dead" as programmed during a gearshift or lock/unlock sequence, and in this case remains DEAD because the engine RPM and the turbine sensor speed are the same just because of happenstance. Until these two speeds diverge there is no way for the controlling ECU to "know" the "unlock is complete. Just another guess. But. If the torque converter lockup could be used full time then the fuel economy and emissions rating between manual and automatic transmissions would be eliminated. But being able to use the torque multiplication and/or the lockup "at will" might just result in better fuel economy and emissions ratings than a manual transmission. In any case it appears that Toyota and Lexus have come a LONG way down the "lockup" road and it's likely there's is not going back absent paying HUGE CAFE and/or CARB penalties.

Sorry, but I quite firmly believe that sometime in the near future "history" will indicate that giving the RX400h V8 performance rather than sticking with the current level of V6 performance was one HUGE mistake. Sure, there are enough "boy-racers" (CHILDREN??) out there to fluff up the sales initially, but I'm betting my money that an I4 with V6 perfromance will eventually win the day. Toyota/Lexus did the right thing, absolutely, in not making the RX an offroader, but now screwed up the formula for further success. Here on Maui "Island in Paradise", gas is almost $3.00.

The is an exhauster port at the very bottom of the driver's side rear quarter panel, if you close up the car and turn the blower to high with fresh air source you can feel the flow with your hand in that area easily. At highway cruise speed there is positive air pressure under the car in this area so very little passenger cabin flow through occurs. If you look at the bottom of th erear window you will notice a small gap between the glass and the rear "shelf" cover, this is the flow through path from the cabin into a channel in the car body immdiately below. I added the fans, two at each end of this channel, within the trunk's quarter panel area at each end of the flow channel. To power the fans I used a diode "or" gate, one from the rear window defroster heating power source and another from a second "pole" of the switch used to modify the IAT sensor. Lexus relies EXCLUSIVELY on the ability of the A/C to dehumidify the incoming airstream and thereby remove and prevent interior windshield and window condensation from forming, EVEN WHEN/AFTER THE A/C HAS BEEN DISABLED BY THEIR OWN DESIGN! So when you switch the system to defrost/defog/demist mode you will often get airflow to the windshield that is as much as 20F cooler than otherwise footwell heating airflow. Airflow that is FULLY SATURATED WITH MOISTURE if it happens that you have driven into a COLD area from an area wherein the temperature was say, above 40F (Seattle to any one of the nearby mountain passes on a winter day). In that case you just might find yourself fully blinded by actuation of the defrost/defog/demist function. To assure that I always get MAX HEAT and MAX BLOWER SPEED in defrost/defog/demist mode I first actuate a switch mounted under the dash by my right knee that adds a resistance into the IAT sensor circuit such that the automatic climate control system sudden "thinks" that the passenger cabin air temperature has just gotten VERY COLD. One side of the DPDT switch adds the resistance and the other side energizes the fans.

"Hate the RX400h." NOT! It's just not my cup of tea.

Basically the problem is that your lexus is too damn well sealed. In order to decrease the operational of load the A/C compressor during the summer months very little air "flow through" capability is provided. As a temporary measure it helps if you lower one of the rear windows slightly to help move the HUMID airflow from the vehicle. While you are in frost/defog/demist mode I would be CERTAIN to lower a rear window slightly. It also helps to lower the windows in the garage at night so most of the day's moisture laden atmosphere can escape. It will help also if you disconnect the electrical connection to the A/C compressor during the winter months. By factory design the A/C compressor is disabled if/when the OAT declines below about 33F. So when you leave your nice warm garage in the early morning the A/C will operate briefly, until the OAT sensor "feels" that outside air temperature, and then it will be disabled. In the meantime it has become saturated with moisture from the incoming airflow and now that moisture will be released into the passenger cabin. As a long term fix I added four 12 volt low volume air exhauster fans within the trunk area to MOVE the passenger cabin atmosphere OUT anytime the defrost/defog/demist mode or the rear window heater is activated.

No, I just think the performance level of my 2001 AWD RX300 is more than adequate, and I don't see the sense in trading even more improved fuel economy for V8 performance in the RX400h. But I'm probably one of the only VOCAL ones that feel that way.