Indyblonde

I have a 2000 Lexus RX 300. I bought it in Indiana and drove it to California this last summer. Here in California, the engine pings very noisily even with the highest octane gasoline. In Indiana it didn't, and I can only assume it's because gasoline is higher octane there, or has fewer emission control additives. Is it possible to "adjust" the engine so that it uses California gasoline without so much noise?

blueridge

You can try resetting the computer. Disconnect the negative cable (black) from the terminal for about 15 minutes.

Also, make sure you're getting gas at a quality company such as Shell. CA does have the most stringent environmental blend required in the US for gas sold in that state.

Pescao

I have the same problem, Haven't figured out what causes it. I even used octane booster thinking that the problem was the gas. Anyone has a hunch?

lexus114

Try a really good cleaner like BG 44K. Or GM top engine cleaner. Or even have it professional done via an automotive shop,sounds like some real bad carbon build up. Maybe even a knock sensor going bad. I don`t suppose you know what kind of fuel the previous owner used do you? i.e brand,octane.

sktn77a

iTrader: (2)

Take it in to someone who knows what they are doing (maybe your dealer, maybe not). It sounds like the spark need retarded but you need to get everything checked before you muck with the ignition timimg. Are the temperatures much higher in california? is your altitude much higher?

Gas octane is not higher in IN than CA. How many miles on the car?

code58

I don't believe the timing can be set on any of the cars with total electronic ignition can it? Meaning there is normally no distributor to set- it is all controlled through the PCM in conjunction with knock sensors, maf sensor, a/f ratio sensors and o/x sensor. Correct me if I'm wrong.

code58

First thing I would do is what the poster said in removing the battery cable for a while. Next thing would be to check for "pending codes" since you didn't mention a check engine light being on. Sounds like the knock sensors should be correcting that if they are working correctly. My DIL's 99RX has only ever used (Cal.) 87 oct. fuel with NO ping which the manual says you should be able to do. The knock sensors should be adjusting the timing even on 87 to totally eliminate detonation.

lexus114

unless its carbon build up.

code58

Lexus- I'm not saying it isn't possible but I have never seen the carbon buildup or even anything close to it that you saw when they used leaded gasoline. I have lived in Cal. for 45 years and have never used anything but regular in anything I have owned, car or truck, even through a 403 cu in Pontiac, a Motor home with 460 cu in, a Motor home with 454 cu in or anything in between. Though in the Midwest the formulation would doubtless be different, they have still used unleaded fuel nationwide since around '73 so the carbon with unleaded shouldn't be a major problem wherever you are.

lexus114

I understand what you are saying,but keep in mind your 460,403,454 (unless modified) are not a 10:5 compression engine. Also,if their is any oil burning at all,or rich fuel mixture,that can make carbon build up too.

Indyblonde

Temperature is much higher of course in the winter. But the octane rating (87, 89, 91) in California are lower than Indiana. The highest octane there is 93, and in Ohio it's 94. My car also got a little over two miles per gallon better mileage in Indiana. - according to the car's measurements, not mine. But I think you're right - the dealer might be worth visiting. Thanks for the comments.

sktn77a

iTrader: (2)

Sorry, been out of town for a week. Code 58 may be right about the timing situation with electronic timing, although these computer settings can sometimes be adjusted. But if you're having pinging on 93 octane gas, something is definitely wrong. Same with the gas mileage - warmer temps usually improve gas mileage slightly. Your driving characteristics will likely be different in CA vs IN - Traffic? Surface streets? Highest octane here in NC is 93 at some gas stations but 92 at others. Never heard of 94 octane street gas before!

code58

I didn't stop to think about the computer being reflashed to make compensation for the lower octane because my DIL's has always run so well on 87. That is something I would certainly look into. I have no idea if the computer "relearns" because of running a higher octane and advances the timing because the knock sensors aren't detecting any detonation. Would be interesting to know. I only know that kind of detonation is not normal and can be pretty destructive to the engine.

Lexmex

Yes, the computer can adjust. I have run the same test down here running 87 and 93 octane.

blueridge

The reason for the computer reset suggestion was going after the simplest and cheapest fix first. The according to the way I read the first post, the symptoms appears after the vehicle was in CA. Unless I read this wrong, the problem was not there during the drive from Indiana. Different elevation, climate, and especially.....different gas. I figured give the computer a shot to learn the conditions this RX is in now and make sure you're getting high quality fuel. How much labor and money did it cost you?