my 99 doesthis: , BUT if I turn off my A/C, it quits, makes me think my A/C is putting a load on my engine what do you think??

I found this:

LSPI and lubricant formulation

In addition to investigating the causes of LSPI, Infineum is studying the effects of lubricant composition to better understand how it might contribute to the suppression of LSPI events. Work has already been undertaken to investigate the effects of using different types and levels of base stocks and additives.

The initial focus of the research has been to evaluate the effect of using different detergent chemistries, Zinc dialkyl dithiophosphate (ZDDP) types as well as varying the levels of other additives.

This research has been very challenging. The destructive nature and random occurrence of LSPI has necessitated the development of sophisticated testing and simulation methods in an attempt to fully investigate the phenomenon. Despite the challenge, the initial findings from this research have identified a number of lubricant and fuel chemistries and hardware and operational conditions that can suppress or increase LSPI activity.

 

Any service or repairs performed immediately prior to knocking?

Otherwise did noise occur gradually or suddenly?

Did you ask a mechanic to diagnose noise??

 

My thoughts, at these higher miles may be time to switch the oil to a high miles formulation and see if this condition continues. Between oil changes are you needing to add oil? The low speed/RPM's was fine when the engine was young and tight, different now that they are in that 200K miles range. Ours isn't as happy to be down there either so trying to get the tranny/RPMS in a better range works for me. At those times in the usual LA/OC parking lot traffic (freeway) I will manually shift down to 1'st or 2'nd.

A pretty complex situation with direct injection engines and when carbon buildup factors in too. Have been reading about VW DI engines as well as some cases of the IS250 issues.

This may be of some interest if not for additional background:

 

A LSI video:
Why you should never lug your engine (Especially turbos)

 

Mike:
in my old days, I would have carbon buildup on the pistons, and I would remove the air cleaner, hold it about 2500 to 3000 rpm and pour water into the carb to choke it down but not stall it, about a coffee can full, and it would have no more carbon build up... but how to do that now ?? I thought maybe pulling it down into first gear and driving it up to 5000 or 5500 for a ways to see if any would blow out (never used any seafoam)
thoughts?

 

I was thinking it could be the bearing in the compressor's crankshaft that is making a noise when the clutch is engaged.

But if you take the AC out of the equation, do you think it could be related to bad fuel? Are any of your coil packs bad or cracked? Spark plugs all in good condition?

Maybe take a stethoscope to different parts of the engine and see if you can isolate it into a specific cylinder.

 

I have mixed feelings about the various cleaners like seafoam. Some instances they can remove trace buildup and others are unaffected. The A/C is a normal operational feature so this shouldn't cause a LSPI incident unless there is some other running situation as Losiracer2 is thinking too. Same gas from the same station? The other thought is an O2 sensor. Yamae might have more insight about whether this could be a bank 1 or 2 that would adjust the fuel ratio for this type of ignition issue.

 

all fuel is from costco.. low or high octane ... same pinging/knocking, (it is not BAD, just there most of the time),
like slowing down to turn and accelerating back to normal.. that is when I hear it..

 

I worry that you have the pre-ignition problem. It is initiated by an ignition source other than the spark, such as hot spots in the combustion chamber. The ECU has no idea to control it retarding the fire timing because the combustion is already started. There are several reasons why hot spots are made. One of typical reasons is the carbon build up in the cylinder or valves.

 

I agree with you, read my #5 above...

 

Billy, what has been attempted so far? Any changes to the LSPI following? Does the car get some good longish runs in?

 

This happens when AC compressor is actuated?

The compressor works off an electric clutch, so a large current draw.....and if the rest of battery storage and charging system and grounding cables not in good shape then perhaps sensors directing engine ECU present false positives from voltage drop.

 

we added some "lucas stuff" when I changed oil (their idea)..
I drive about an hour at 70-80 mph .. at most.. usually 15-20 minutes 30-50 range..

that is about it..

 

The manual in my 06 RX400h calls for 87 regular.

 

Update Billy?

The LS400 will run on 87, very different engine architecture, the manual and filler door both are for premium fuel fills.