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Vehicle is a 2000 RX300 AWD, concern is when driving on steep grades car slows down and doesn't seem to have much power where it is not responsive when I depress on the accelerator.
In the period of about 10 miles there is close to a 2,000 foot elevation gain.
Each time I drive this I get scared and feel like I am going to come to a rolling stop, the car slows down from 50 mph to 40 to 30 to about 25 and then I eventually make it.
I have the over drive turned off but that doesn't help much, should I switch the transmission into PWR (Power) mode where it changes the shift profile or just leave it in 2nd gear and let it rev around 4,000 rpm?? Ideas?????
I find my RX300 slows down and doesn't react much to the gas pedal. One reason and the main reason I believe is my driving habit. I usually drive in the slow lane and baby it keeping an eye on the fuel economy readout. I think this is my problem, where instead I should have a good running start keeping the engine rpm and momentum up. I find that the transmission tends to want to keep the vehicle in high gear which makes the engine struggle to deliver power. Another option would be to put the transmission into 2nd gear and let the engine rev to around 4400 rpm.
does this make sense??
Do you think I have a clogged fuel filter that is limiting the fuel?
While driving the vehicle to work today I had some nice hills to go up. I put the transmission switch in power mode and put my foot into it and it did well, the hills were nothing like the long grade of Donner Pass. I believe it is my driving habit and need to put my foot into it a bit more and let the engine rev.
I am not sure if the altitude has much to do with it, 7,000 feet. I recall taking a 1979 diesel Rabbit up there in the 80s and the car barley made it up the Donner Pass. Also I had a 1977 gas rabbit that would die on the summit from running too rich, I would have to take out a 3mm allen wrench on the side of the road(lucky I had one with me) and adjust the mixture and ritchen it up. The 1977 Rabbit was fuel injected with Bosch CIS but didn't have a lambda (ox sensor) so there was no feedback.
a mechanic friend send me the following about the RX300
That's a **** of a climb for a car.....94 HP out of the wrapper don't help either.
If no codes and otherwise good running:
Sounds like it's just underpowered for the task.
The only alternative is, as you say, drop the transmission selector down a gear or two and let it rev a bit.
220 hp @ 5,800 rpm shows as your max HP on that car (You sure as **** are not going to let it do that, I hope), but more importantly:
Max -torque- is 222 ft-lbs. @ 4400 rpm.... so 4,000 RPMS for the limited time to get over the hill don't sound too bad (to ME anyway.....but WTF do I know?).
Hill climb racers don't get up to the top doing 2000 rmp in 4th gear......
Sometimes you just have to drop down and give it the juice.
As you go higher, your engine is consecutively receiving less oxygen. hence, reduced power. This is why super and turbo chargers are norm on airplane engines. To pump more oxygen through.
That said, you need to do one thing:
ditch your air filter and replace it with high air flow one. Septre, for example. No need to pay grossly for K&N. I also just bought HAF filter on Amazon for $16 for my NX. Same difference as K&N or Septre. Fraction of cost.
Also, you may consider a higher octane for trips like this.
Oh, and we towed trailer, when moving, with our RX300 from Nashville to Seattle. That comes with countless mountain passes going through Rocky Mountains and Oregon. Never a problem. But, all my cars run on HAFF
You're losing about 45 HP at 7000'. If you're spinning around 3000 RPM, you might only be putting down 50-75 at the wheels. Not much to work with for a heavy SUV.
What is the mileage of the RX? Almost 20 year old vehicle and you may not live in hilly place, so ECU is not adjusted to the situation.
I live in the foothill of Rockies in Western Canada. My house is at elevation of 1040 meters. Our cabin is located at little higher
elevation. I never owned any vehicle more than 5 years old. My car just maintains speed pretty well following cruise control setting
whether I head to the West or East.
As you go higher, your engine is consecutively receiving less oxygen. hence, reduced power. This is why super and turbo chargers are norm on airplane engines. To pump more oxygen through.
That said, you need to do one thing:
ditch your air filter and replace it with high air flow one. Septre, for example. No need to pay grossly for K&N. I also just bought HAF filter on Amazon for $16 for my NX. Same difference as K&N or Septre. Fraction of cost.
Also, you may consider a higher octane for trips like this.
thanks for the reply
Yes, I heard about the elevation effect, I recall hearing something like 3% loss per 1,000 ft. I am coming from sea level so at 7,000 feet that would be a 21% loss. I've read that the RX300 puts out 94 HP so that would be a loss of 20 HP so effective horsepower of 74 HP?
I could try another filter but may not be able to get it in time , I doing the drive this friday.
As you go higher, your engine is consecutively receiving less oxygen. hence, reduced power. This is why super and turbo chargers are norm on airplane engines. To pump more oxygen through.
That said, you need to do one thing:
ditch your air filter and replace it with high air flow one. Septre, for example. No need to pay grossly for K&N. I also just bought HAF filter on Amazon for $16 for my NX. Same difference as K&N or Septre. Fraction of cost.
Also, you may consider a higher octane for trips like this.
as for the higher octane, I recall reading the opposite? I heard for cars that require high octane fuel, that they can get away with not using high octane in higher elevation?
Oh, and we towed trailer, when moving, with our RX300 from Nashville to Seattle. That comes with countless mountain passes going through Rocky Mountains and Oregon. Never a problem. But, all my cars run on HAFF
You're losing about 45 HP at 7000'. If you're spinning around 3000 RPM, you might only be putting down 50-75 at the wheels. Not much to work with for a heavy SUV.
Thanks for the reply
I thought the loss was 3% per 1,000 feet? How did you come up with a 45 HP loss?
What is the mileage of the RX? Almost 20 year old vehicle and you may not live in hilly place, so ECU is not adjusted to the situation.
I live in the foothill of Rockies in Western Canada. My house is at elevation of 1040 meters. Our cabin is located at little higher
elevation. I never owned any vehicle more than 5 years old. My car just maintains speed pretty well following cruise control setting
whether I head to the West or East.
I was just driving home and got off the freeway and then back on where there was a metering light. So I was at a full stop and then took off with the stopwatch feature of my cell phone. I put my foot into and then didn't go all the way to the floor untiil a coupld of second into it, I guess I chickened out a bit, it rev'd up to a little over 5k before it shifted. Was watching the speedometer and my thumb on the stop button and it was 10 seconds. So I might have lost 1 second not taking off hard enough so I guess it seems like I am in line with around a 9 sec 0-60.
Again, this is my first time jumping on it hard so was a little hesitant as I was concerned I might cause some harm or damage.
On the rest of the ride home I put my foot into it alot more and the vehicle had lots of pickup and zip. Perhaps it has been my driving habit of driving easy in this vehicle
Earlier today I removed the mass air flow sensor and sprayed it with some cleaner. Not sure if this has anything to do with it.
03-20-18, 01:30 PM
Driving steep grades with large elevation gains
