wwest

"A/C temporarily on vacation...." I assume you mean something about the "A/C" has failed making it inoperative... IN the meantime you can check the positioning of the reheat/remix vane inside the plenum by checking the push/pull cable that operates the hot water valve inside the engine compartment at the top center of the firewall. Going from max cold to max hot should result in the cable moving the hot water flow valve from fully open to fully closed. With the valve fully closed the mixing vane servomotor should be positioned so no air is reheated.

All of the new car fuel systems run continuously under a slight vacuum. If the vacuum is lost for some reason, gas cap is opened without refueling, the CEL will come on. If the gas cap is opened and the fuel level in the tank rises, SOP, then the ECU ignores the temporary loss of vacuum. If the gas cap being removed absent refueling the fault code should clear after a few city/hwy drive cycles. Or you can disconnect the battery for 10 minutes or so.

The knock sensor could had been bad all along but could not be "uncovered", detected by the ECU, siince the failing oxygen sensor "shadowed" it. A/F ratio sensor is the oxygen sensor before the catalyst vs the one after.

About the SC Studebaker..?? No, I think it was called the Super Hawk or Golden Hawk. Just googled it, it was 1957-58 Golden Hawk.

Did you know that back in the fifties Studebaker used a variable speed supercharger that automatically adjusted the "charge" rate as a function of engine RPM/Load? No "pop-off" or bypass valve required and no supercharger noise at all unless high torque was in order. Used an adjustable "V" pulley and belt much like some modern day CVT's.

Brake regeneration modifications. There may be a limit, a rather serious one, to the rate the batteries can be charged. Has anyone given consideration to the use of a small genset, say a Honda EU2000, to continously charge the Prius' hybrid batteries? Firing up the 1.5L I4 to simply recharge the hybrid batteries seems a waste, a horrible overkill.

I cannot imagine that a conventional turbocharger would be beneficial given that the Prius uses the atkinson cycle, leaving very little heat/energy in the exhaust system for a turbocharger. Personally given the level of battery energy readily available I would use a supercharger driven by a small motor with a PM rotor and a variable frequency high voltage A/C drive source. The turbine section of a turbocharger might be beneficial if used as both an alternator and an exhaust muffler. Use the exhaust gases to turn a turbine that in turn drives an alternator which charges the battery pack at variable rates in anti-phase with the exhaust pulses. Smoothes the flow of the exhaust gasses, quieting the exhaust significantly, while simultaneously recovering energy that would otherwise be completely lost.

The fun part is that the ABS brake pedal vibration was incidental, not at all intentional.

Personally I love it! Much better than a simple beep and/or visual indicator, especially ones that quiets or extinguishes before the driver can acknowledge the event. Like the way the brake pedal vibration "tells" you that the roadbed is too slippery for hard braking and directional control simultaneously, the "new" stearing wheel indication will instantly "tell" you what is wrong and how to help correct it. Keeping the driver in the control loop. Unlike the BMW system that will simply counter-stear the vehicle against your own stearing inputs in these circumstances

TRAC.....as a teaching tool. MY 1992 LS400, RWD, came with one of the early versions of TRAC. Basically the way it operated was that at the instant driven wheel slippage, spin, was detected it would start applying both rear brakes and simultaneously dethrottle the engine down to something just a bit above idle. I came to consider it more as an early warning of slippery conditions that I could not note visually. My practice was to then turn it off and drive with an imaginary egg between my foot and the accelerator pedal. By 2000 the system had been somewhat refined in that my MY2000 GS300 would still instantly apply the brakes but delay the onset of engine dethrottling for a few hundred milliseconds to give me time to react to the conditions and lift, "feather" the throttle on my own. Then there was the MY2001 AWD RX300. Being predominantly FWD there was NO delay between the onset of wheelslip/spin and engine dethrottling. In a FWD vehicle that few hundred milliseconds of delay before dethrottling can too easily result in a serious accident. Uncontrolled wheelslip/spin at the driven wheels of a FWD vehicle can potentially be a lot more hazardous than the same situation in a RWD where the driven can still maintain directional control. So, my advice is to avoid driving FWD or front biased AWD (transaxle types) on adverse roadbed conditions whenever possible. Like a 4WD/4X4 they give you a false sense of security since their forward weight bias coupled with FWD allow you to accelerate or start up from a stop more readily. But even worse than a 4WD/4X4, ALL, or almost all, of the engine torque is being delivered via the front wheels, that's not good if you find you need to "leverage" the front tires into some level of lateral control simultaneously.

Is getting an entirely new AWD system design, full time, but with a switch that allows you to lock the torque distribution at 55/45 F/R. Also new is electric only stearing with a "stick shaker" effect on the stearing wheel when VSC activates to prevent you from turning the stearing wheel in a way that would exacerbate overstearing or understearing. Will the 2006 RX330 also get these features??

"Of course a lot of the cars I've seen get into trouble in the Sierra do it on the downhill. FWD and AWD don't make much of a difference when you aren't needing to apply drive." Except for engine compression braking on a FWD vehicle going downhill. The equivalent of throwing an anchor from the front, bow, of a boat while underway. Then throw snow chains on the front, driven wheels, of one of these vehicle and you have a recipe for disaster.

Some of the earlier A/C systems used a relay, to avoid the small voltage drop across a transistor, to run the blower on mAX speed. Sounds as if the relay contacts are stuck shut or in the alternative the speed controlling power transistor is shorted.

That sounds exactly like my problem. Thanks for responding. Do you know what the sensor looks like? I looked underneath the passenger side headlight around the bumper and I see what appears to be an electrical connection plugged into something about a square inch in area. If that's it, it looks plugged in but it might be a bad sensor, or perhaps there's a bad connection somewhere else. WWest, no, the outside air temperature seems to be spot on, but thanks for the suggestion and for continuing to think about it. ← The temperature sensor mounted on, behind the front bumper is the OAT sensor and is used as an A/C input and for the OAT display. Sorry.

Is the outside temperature indication correct? An open OAT sensor will indicate and extremely low OAT and that will result in your problem.

"Problem filled......" No, I did not say that. More complicated, yes, but problem filled? Not to my knowledge. ← By problem filled i meant all the premature rx300 AWD failures. It does seem that the FWD's don't have as many problems. Less moving parts = less posibility to break. ← Is it really conclusive that the premature transaxle failures are unique to the AWD model? I have always been of the mind that the premature failures or the result of the inadvertent upshifts during coastdown which leads to the need to quickly downshift if the gas pedal is depressed shortly after the upshift. In later models Toyota alleviated the premature failure problems by delaying the onset of engine torque in these circumstances using an e-throttle. Does anyone know for certain what part or component is failing prematurely on these transaxles? Due to the level of debris in the sump pan and the burned odor of my ATF at only 40,000 miles I have assumed it is the frictional surfaces of the transaxle clutches that are wearing out more quickly than the designers expected.

Door switch failure, sticking, is a VERY common problem with the early series. Probably due to aging of the rubber cover.

Does anyone have the sequential shift system and is experiencing the hesitation symptom? If so can you try an experiment for us? Do a couple of downshift "nudges" of the sequential shifter when you know you might, may, encounter an acceleration recovery problem, hesitation, from an inadvertent upshift during coastdown. I can't do that myself because the only downshift I can command is all the way down to 2nd.

If you can remember. or have encountered, the "feel" of non-assisted braking vs assisted you can more likely relate to the new, additionally assisted BA, Brake Assist, systems. Basically when the BA ECU "senses" a panic braking situation it "takes over" and provides additional braking pressure from the Trac pressurized brake fluid accumulator. That's why it is so easy to depress the brake pedal in these circumstances, you are getting extra "assist" beyond the normal power braking level.

What is the relative cost, based on miles driven/unit, of filling the CNG tank from your home natural gas source (no "road" taxes) vs gasoline? And we're not talking about eliminating the gas tank, most conversions allow a switch-over if the CNG is exhausted.

"Problem filled......" No, I did not say that. More complicated, yes, but problem filled? Not to my knowledge.

No.

Yes, phill is the home fill system and I have seen picture of the CNG tank mounted just behind the back seat. Can't help but think of the Rx400h converted to CNG with a small CNG compatable genset to continually recharge the hybrid batteries.

If you have the money then spend it.

Why not add a compressed natural gas tank and a smallish genset, say the Honda EU2000, to continuously charge the hybrid batteries? Natural gas can compressed and pumped in at home and with no road taxes.