zach

Perhaps it's just because the car has been sitting overnight, but I'm not sure... When I go to start my 1997 ES 300 in the morning the engine revs up to 2k rpm and sounds like it's racing. It doesn't subside until I put it in Drive or Reverse, and then when I park it it goes down to its usual idle of 750 or 1k. Am I just paranoid, or does this seem a little weird?

rcwelch

Zach...I have a 2000 ES and it does the same thing. I suspect that the idle is electrically controled until everything warms up a bit. Does anyone know for sure?

mmarshall

2000 RPM may be a little high, but it's pretty much normal for it to idle around 1800 RPM or so on a cold start if the temperature is below about 40-45 degrees or so, and the coolant temperature sensor and fuel injectors are working properly. The fast idle and rich fuel mixture on a cold engine helps get oil pressure up and overcome the tendency of cold engines to stall. The idle speed should gradually diminish as the engine warms up....again, if the sensors are working properly. On a cold morning let it warm up for about a minute or so...by then the RPM should drop a little. Then shift it in gear and drive SLOWLY (under 3000 RPM) until the temperature gauge is a couple of notches up....about 140 degrees. Many automatics today will not upshift into high / overdrive until you get to this warmup point...no matter where you put the lever. That is done for emissions.
Many Lexus products do not "clunk" or jolt when you shift from Neutral to Drive at fast-idle RPM like some other cars do because of the "Shift Shock" control....this feature, unlike cheaper Toyotas, momentarily, for a split-second, grabs high gear instead of first, then grabs first. By doing this you get much less of a jolt.....in my IS300 you cannot feel it at all. It's just one of the nice features you get when you spend the extra bucks for a Lexus.

steviej

iTrader: (1)

zach, its normal. Emission controlled to warm the car up faster. You will also notice that on cold mornings that is revs higher before it shifts out of 1st and out of 2nd. It all goes away as the car warms up.

steviej

zach

Okay, thanks for the great replies. This is happening in Phoenix, though, where the morning temperature is like at least 65 or 70 degrees F. I just thought it was a bit odd. I haven't let it run for a couple minutes, but I'll try that tomorrow morning and see how it is.

Thanks again!

mmarshall

This is not often likely in Phoenix's warm, dry climate, but you have the windshield defroster on while idling? On many cars, that automatically engages the A/C compressor to provide a source of dry air, (on Lexus cars, I think the compressor runs with the defrost above 35 degrees) , and when the compressor is running, a solenoid will kick up the idle speed about 200 RPM or so to compensate for compressor drag. Make sure the front defroster is off if you want a lower idle speed.

That brings up another point many people ask about. When you DO have the defroster/AC compressor on, you have to ad a little heat to keep the front window from becoming chilled by the AC blowing cold, dry air on it. When that happens, then you get moisture condensing on the outside of the glass and you have to use the wipers. A little heat added to the defroster will prevent that from happening....and ALWAYS use the fresh-air mode in defrost....NOT the recirculate.

steviej

iTrader: (1)

it is not really a question of the temperature of Phoenix as it is a temperature of the coolant, exhaust gasses, oil and air/fuel mixtures that determine the rpm and the length of time that the engine revs high.
For emissions purposes, the car will run in an open loop until the certian air/fuel/coolant temperatures are met, then the engine runs in a closed loop and the rpms drop to the normal idle.

mmarshall also brings an excellent obsevation to the table.

steviej

amf1932

The warmer the ambient temperature, the quicker the engine will come up to operating temperature.

It stands to reason that bringing a cold engine from about 30ºF to operating temperature will take longer then raising a cold engine from about 70º to operating temperature. Am I correct in this assumption?

steviej

iTrader: (1)

Alan you are totally correct.
My point is that the normal operating temp of the motor is much higher than even 70°. So even in hot climates, there is still a warm up period for the motor.

steviej

Lexusfreak

Agreed I asked pretty much the same questions on this issue zach with regards to my 01. More experenced members assured me that this is normal & I don't even think about it now Just takes some time to get used to the car & how she is designed to operate as this is my first Lexus (Toyota) product. Not my last to be sure I might add

mmarshall

This is not necessarily the tranny cold-shifting at higher RPM but giving the impression of doing so, because on cold mornings, like engine oil, the tranny fliud will be thick for the first half-mile or so, creating more hydraulic pressure and firmer shifts. So the tranny may feel like it shifting at higher RPM but it is actually just the firmer shifts at the same RPM due to thick fluid. Of course, how much gas you're giving it makes a difference, too...but of course you shouldn't take a cold engine over 3000-3500 RPM anyway. After the first two minutes or so....when the tranny fluid warms up sufficiently, Lexus transmissions are probably the smoothest ones on the market.,

amf1932

The delay in transmission shifting when cold was purposely designed into the operation of the ES's. This is controlled by the engine computer and NOT by the thickness of the lubricating fluids.

mmarshall

Yes, the delay is computer controlled...on my IS300, there's a minor cold-temperature shift delay from 3-4 and a longer delay from 4-5 (the 4-5 occurs at 140 degrees engine temperature and is emissions-related). The ES is generally similiar. What I was referring to with the thick, cold tranny fluid was the firmness of the shifts, not shift delays. The cold, thick fluid causes a bumpiness and a lurch during shifts that disappears as the fluid warms up.
Sorry if there was a misunderstanding there.