BOWTIE 3

My wife's 2000 RX300 [ 54,000 miles ] has had a periodic gas knock for the past year or so. We've always used 89 octane fuel in it and generally get it from BP/Amoco or Shell. I've had it in to the dealer several times in the past year for this problem and always leave dissatisfied. They continue to tell me that it's the fuel we're using. I've even used 93 octane several times and had the same result. It used to happen right after a fill-up, but lately it will do it at a half-full tank. Everything is normal and then taking off from a traffic light and BINGO, there is the gas-knock again. When it happens I pull the ECU-B fuse for a few minutes and that solves the problem til the next time. I put a bottle of Chevron Pro-Guard in it about every 3 months. Does anyone have any ideas about this problem? Thanks.

HarrierAWD

It could be carbon deposit. I had that problem with my last car. Only Chemtool B-12 cleared it up. Don't waste money on other additives. They don't work.

BOWTIE 3

I've heard of that. Does any auto parts store carry it? Maybe NAPA?

HarrierAWD

I bought it from AutoZone. It's been at least 6 years so I don't know if they still carry it.

flipside909

Definitely carbon build up. If you can find it, some places use the Bilstein RU2000 engine flush system. I highly recommend it if it's available in your area. Try to stay consistent with gas brands...preferably one.

HarrierAWD

Engine flush won't help because it won't get into the combustion chambers to clean up the carbon deposit. Chemtool B12 mixed in gas will. It took only one bottle to do the work for me. Prior to that, I tried several bottles of EACH big name stuff - such as Chevron Techron, Gumout, and STP Injector Cleaner. They didn't do jack.

Brands of gas doesn't matter. I use mostly BP because I get rebates, but I occasionally use just about all major brands of gas. I use octane 87, never had a single knock in my RX300. No more knock in my old car either after I cleaned it up with Chemtool B12.

flipside909

Well i'm speaking from experience on my 1990 Toyota Corolla LE. After trying to bump up the octane, the engine would still ping going up hill obviously and regular acceleration w/the a/c on. After the flush was done, we stuck back on 87 on the same conditions and the little 1.6L 4A-FE ran beautifully. Since that point, i've used Chevron strictly and quit using Arco, Shell and 76 since those were the stations we usually filled up with at the time. If the other things didn't work for you, then fine. You already made your points before, i've made mine.

I've never had pinging problems with my 1MZ-FE V6 Avalon and 1MZ-FE V6 Solara. The Avalon had well over 100k and my Solara currently has 97k.

SCV8

Anyone have problems with the engine running on after you shut it off?

HarrierAWD

You may have confused engine flush with fuel injector cleaning service. Anyhow it's nice to know your problem was resolved.

The $3 Chemtool does the work vs. $60-$100 auto shops may charge for such service.

JDMHARRIER

the berryman b12 chemtool TOTAL FUEL SYSTEM CLEAN-UP. works pretty good .. i got a box three months ago from autozone..i use a bottle every 3,000 miles or every oil change... you can find them at ur local autozone

flipside909

The $3 bottle of Chemtool is just a temp fix for a minor problem. If you have major carbon build up, thats when a machine flush should be used. The 4cyl in the Corolla was more prone to pinging, smaller displacement, low hp motor. I've rarely come acros a pinging V6 unless it was overheating or really had poor maintenance.

flipside909

Every 3k is overkill. The chemicals used in any over the counter fuel cleaner will damage your fuel pump diapragm if overused. Beware.

Jeff92se

Alot of these chemcials have ingredients that contain octane boosters. So if you noticed less knock, it could have been the result of the slight octane boost, not from any actual cleaning.

The only way to really tell is to take out one plug and shine a light down and notice the top of the piston. Use the Chemtool, Seafoam or etc and then take out the plug and note any changes.

But using this method won't clean out the dirty intake manifold resulting from the EGR or PCV. Some opt for using Seafoam though a VERY small intake manifold vacuum hose, shutting the engine off for 5-10 min than running it. Then note the huge white smoke show. haha

parula

I haven't had a knock on my Lexus 300 but thanks for the tip, my Honda could use it, Chemtool B12!

lexus114

Also BG44K works extremely well.