ilanh

I am using Falken 205/70, the tire size and psi are the one recomanded by mfg on the label in the driver door frame. Can I put more psi the mfg recomanded if allowed by tire?what % improvement are we talking about? Seems to me that with 5.5 km/l I am still far from what the car can/should do

Lexmex

Ok, I made the same mistake a long time ago with my first car, too. The psi shown on the door panel is for the tires that originally came with your vehicle and has no relation to the 205/70/16 that you are using now. If you let me know the max psi shown on the side, I can tell you about what you can safely run it at. For instance, I've got 235-70-16 Michelin CrossTerrains that have a max of 44, but I can run them at 38 or 39 psi with no issues. You can do a similar ratio there. In addition, I've been running nitrogen in them for years principally to reduce the tire pressure loss over time (still occurs). The improvement is going to depend on where you were over where you're going to shoot it up, too. I don't shoot it to high or I am going to get tire wear issues, but the nitrogen also an effect of rounding out the tires (makes it feel a bit more like you're in a tank compared to air when the tires are at the same psi).

I don't rule out an issue with your fuel injectors. Every so often, I'll have bad gas mileage and I realized there's crud in my tank and needs to be cleaned out (I guess Mexico still let a lot in there I still need to work on).

Also should check your alignment and tire balance. Sometimes, it's not just one thing, but a bunch of things coming together, hence the need for a tune-up, but usually something like tire pressure or fuel injectors can be an issue.

I currently am working on a gas mileage issue I've had (that I think is crud in the tank related) and plan to have my laptop scanner in the next few days to see where the issue is coming out of and then I may be able to give you some more answers on that.

sktn77a

iTrader: (2)

Your original tires (215/60R16) would give you roughly 10% worse gas mileage, just because of the diameter (gearing) difference. Your new tires are still smaller than stock (225/70R16 in the US) and will give you a roughly 5% worse gas mileage. However, you are still getting MUCH lower mileage than you should be, even with either of these tires.

ilanh

To clear up tire info (I made some errors before):
I am using Falken 215/70 R16, the max psi on the tire is 51 psi, I am filling 30 psi
Before is was Bridgstone 225/65 R16

ilanh

to Lexmex:
What can I do to clean/check the fuel injectors?

to sktn77a:
My tires are Falken 215/70 R16, it says 51 max psi on the tire, what pressure can i use? rear/front?

to others:
I still have a problem when stoping in downhill for a while the engine will sometimes hum (increase RPM suddenly) like trying to move forward even I am pushing the break pedal. I didn't find and clue/hint on why this happens or intiated.

Lexmex

I deleted my post and your following post. There must have been a technical error, because I gave a pretty long response that I remember, so I'll have to see what is going on with our system. Let me answer your questions in two separate posts.

What I said earlier is that you could first try going up to 35 psi and if you see an improvement there after about 3 days, move it up to no more than 40 psi for tire pressure and then see if there is any improvement at that point in your gas mileage. I run a 38/39 psi with a max of 44 psi on my tires.

I've mentioned a lot about my using nitrogen in the tires. There's many reasons for this and it's generally not expensive. In the United States and even when I lived in Mexico, it ran to about $20 to $30 for all 4 tires (that's total and not each tire).

I am not sure where in Hong Kong you can get nitrogen, but I do remember seeing a vendor of the equipment for nitrogen machines in Hong Kong and their number is +852 (2) 428 8008 and they sell the Parker Hannifin machines, which I remember seeing in Mexico.

Keep in mind, that the tire pressure shown by Lexus or Toyota or for that fact any manufacturer is the one related to the ORIGINAL tires with your vehicle. Each tire has different maximum psi settings. We have members all the time changing out their tires to mostly bigger ones and of course the tire pressures are going to be different.

With the injectors, you really need to get a good quality fuel injector cleaner. I mentioned earlier Liqui Moly's Jectron cleaner. I usually recommended that internationally, because the other cleaners common to the United States are generally not as widely available overseas. I checked in Hong Kong, and there are some options.

My favorite cleaner is the one from Redline, http://www.redlineoil.com/product.aspx?pid=80&pcid=12

In Hong Kong, try

Join River Development Ltd.
852-2954-9251

I used this the other day as I still have a lot of issues with bad stuff at the bottom of my tank (there must still be a lot from Mexican gas from 1.5 years ago that is caked in down there), because with my OBD2 laptop scanner I got some odd readings on the A/F sensors just under 1/4 tank (that shouldn't be) with the readings flying around. In addition, I had some minor issues starting the vehicle, but eventually it turned over and now starts up without problem after adding this cleaner.

If for some reason that doesn't work, one other cleaner that I've used, but am not of the opinion it is superior to other cleaners I mentioned is the one from Nology, http://www.nology.com/powerboost.html

Where I found this useful was when I had A/F sensor issues and this seemed to do the trick in clearing up errors when I had them in Mexico, but again I used this a lot because other cleaners were scarce or extremely expensive and I needed something less costly and more available.

In Hong Kong try,

TOP RACING GROUP LTD.
Shop No. 6, G/F, Sino Industrial Plaza
9 Kai Cheung Road
Kowloon Bay, Kowloon
Phone: [852] 2311 1668
Web: http://www.topracing.com.hk
e-mail: info@topracing.com.hk

salimshah

Word of caution on inflation of tires:
During inflation [more so as you are near the tire] and any time later, If the tire bursts, it can be lethal. There is no safety mechanism. If you see the tire people work, you will note that they put the wheel in a cage as they inflate them.
I am only going to say, be careful as you deviate from specified tire pressure. Fuel economy is not the ONLY important thing. If it was, you would not be driving a SUV.


My fuel economy has taken a turn for the worst, ever since I cleaned my MAF. .. I was running lean. I was averaging 19.2 and now down to 18.4mpg

Ever since I used fuel injector cleaner, my RX sounds different. Seems like it is drawing more air [just a feeling ... no scientific data].

Salim

Lexmex

That's almost assuredly related to the ABS (anti-lock braking system). This has been one of those issues we've had a hard time dealing with and especially at minimal $$$ cost.

What occurs is that when you come to a full stop, the vehicle will lurch forward even if your foot is on the brake pedal.

One of the first things we tried was this,
https://www.clublexus.com/forums/rx-...when-rain.html

in order to clean the sensors. That worked for some and not so well for others.

Another possibility is that you have a bent axle (and that's $$$).

I had this issue in Mexico and it perplexed me and I finally took the escape route and disconnected the ABS system itself (though it does leave the ABS light on the dash for now) as shown here, https://www.clublexus.com/forums/rx-...000-rx300.html and https://www.clublexus.com/forums/3253699-post5.html

If you pull out that connector, it will leave the ABS light on, but I've had this on for a few years now and I brake just fine, even in rainy weather. The issue with braking and then with the vehicle lurching forward is also gone.

Barring that, you're looking at taking it somewhere like the dealer and they may suggest something as ridiculous as replacing all the wheel sensors and the ABS system, which really shouldn't be necessary at all and I refuse to do anything like that.

There is another possibility that your IACV still has issues and should be cleaned along these lines, https://www.clublexus.com/forums/rx3...-write-up.html

ilanh

Lexmex: thanks for your details answer!

RE: Tire pressure - I will try and report

RE: Injector cleaning - could this be related to the poor fuel consumption I have. Generaly fuel in HK is very clean, I just wonder if the fuel consumption might be relatd to that. Note that most of my drive are in hilly densed city (HK island).

RE: car lurch forward in downhill - what do you mean by "bent axle", do you mean the piece between the read differential to the wheel? I am asking since as mentioned before I do have a "knocking" sound from the left rear side while start accelerating uphill from full stop untill the car reach 20km/h (approx).

RE: Trottle adjustment - can you explain the function of the 2 screws adjustment shown in the pictures (Lexmex, I used your pictures - thanks!):

In the upper picture the screw is at the bottom of the "half circle" part, you need to pull the cable and rotate the trottle to see it. It seemed to me as soemthing releted to the chock so when I cleaned my IACV I released this screw about 2mm. I don't really know how to adjust this screw properly.

The one in the lower picture (screw between the 2 intake hose) seems to me as the trottle minimum position adjustment. I didn't touch this screw.

Lexmex

I am not sure exactly what you are trying to do with the throttle here, but I'd have to write a near book to explain how to use those and it would take me the better part of day to photo and write up.

Yes, you're injectors can get dirty over time and there can be bad contaminants at the bottom of the tank. Happens everywhere regardless of the supposed quality of the gas. I get ethanol issues in my tank here in Florida, since up to 10% ethanol is added to the gas here. I had sulfur issues among other things with the gas when I lived in Mexico.

Even in Hong Kong, I've heard of people getting accumulation of muck at the bottom of their tank after awhile. One way to spot this is that the low fuel light will come on earlier over time.

The axle I am talking about is related to the front or rear wheels and it's the long metal piece going across from wheel to wheel, i.e., what turns when the wheels turn. It's an outside possibility, but rare.

Protch

hello, i fixed my car now , lots of stuff , i was get a code about O2 sensor, and i resolve it now ,
but i still getting bad gas 18L/100KM 14.
and while i driving i found something i can't understand. star engline i need above 3secs, but engline works fine ,very quite , 800 RPM idle standing very well,
and i had hear a ticking sound form under my fuel tank , it's called charcoal canister , and i don't understand what's work for . if you let me know about it , i relly thanksful , sorry my bad english

salimshah

Yesterday on NPR they were saying the % ethanol will be raised every year.

Salim