Help... My 2000 rx300 with 77K will have an engine knocking noise during acceleration. Dealer tell me I'm using cheap gas but I'm using premium grade.

Any suggestion I could troubleshoot this?

thx

BTW... Just want to say thx to all the contributed to this forum. Very informative.

JCL

 

Have you checked you oil level?

 

do u encounter this when you accelerate and it shifts...my car has 65k and has been jerking when it shifts, the shifts aren't smooth...

 

Is it really knocking or pinging? An occasional ping here and there is ok. But if the engine has had regular oil maintenance it shouldnt knock. The 1mz-fe engine is very sensitive to pre-detonation or ping.

 

thx for all the replies...

It is definitely knocking. If I add fuel additive, the sympton improves a little.

Oil leve appears OK. use 5w30

The car does not jerk when shifting.

JCL

 

It's the classic carbon deposit issue. Using high octane (94 or above) tend to do that. The RX's engine can handle up to 93 octane at sea level. Anything higher will give you incomplete burn, thus carbon build-up on the piston heads.

From my experience with my last car, only Berryman's Chemtool B-12 works in cleaning up carbon deposit. Pour it in the gas tank. Don't waste money on Techron, Gumout, or STP.

GM's TOPS cleaner also works, but it's way too much trouble since you have to remove the plugs and pour it into the engine. Not recommended since the rear 3 plugs are way back there.

Once you get the engine cleaned up, use only regular or mid-grade gas.

 

thx.

One more question, shouldn't the knock sensor detect a engine knock and self-adjust?

 

Polyether Amine (PEA) is proven to have carbon cleaning ability, higher % of PEA will give you better carbon deposit cleaning ability. See this link

http://www.enertechlabs.com/gasoline_problems.htm

If you research around, you will find not all fuel additives are created equal. This holds true even within the same brand since many products are marketed. It is higher PEA% you are after, the rest of the stuff is just kerosene, which acts as a carrier to PEA.

BK 44K is very strong and effective, but it is expensive and not as easily avaliable, see this thread
http://theoildrop.server101.com/foru...&Number=855661

Here is a guy that summarized PEA% from MSDS data published from various OTC brands. They are cheaper fuel additives that have various level of PEA. However, they are not as heavy duty as BK 44K, but for light cleaning duty, one can't beat the semi-annual Techron Concentrate Plus or Gumout Regane Free After Rebate offer at Autozone! Talk about free preventative maintenance and save a little on gas.

http://theoildrop.server101.com/foru...&Number=767794

My suggestion is unless you got a serious problem, 2 Gumout Regane (Autozone) or Redline SI-1 (Advanced Auto Parts) in a row should do the trick. I too suggest never go beyond octane rating 91 and above, remember higher quality gasoline for our engine does not means higher octane rating automatically.

 

Yes, but the knock sensor cannot help much here. When you have carbon deposit, two things can happen: #1 - The carbon deposit reduces the combustion chamber size, which results in premature detonation (knock or ping); #2 - The carbon deposit gets so hot, it ignites the fuel-air mixture before the spark plugs do.

The only solution is to get the carbon deposit cleaned up. Note that most "injector cleaners" simply increase the octane level to "mask" the issue, making the users think that the products work while the underlying carbon deposit problem remains. Do a Google search, you can find over 50 products that make great claims but fail to deliver in reality.

 

i've noticed some knocking on ours, but it's a 2000 with 175k miles on it. it only knocks when it's under load at low rpm's like pulling up a steep driveway. we only use 89 gas.