I have an '06 6spd with 120k. I experience engine knocking at 4k rpm at half throttle. If I give it more, the knocking seems to go away, or maybe is just less noticeable. I used to run 93 octane, until I moved to Cali. Now I'm limited to 91. The knocking happened with both grades of fuel and isn't much worse on the 91 octane.

Any suggestions on where I should start checking?

 

Anyone? Would love some insight, if anyone knows.

 

Have you changed your spark plugs? I had pinging as recently as 2 weeks ago and after 3 tank fulls of 93 octane and a bottle of techron chevron my pinging is now gone. I will now be going back down to 91 octane.

 

How long ago did you move to Cali and what brand of gas are you using? I knew a guy that tore the engine out of his turbo car that he took from Texas to Cali because of drivability problems he couldn't fix. It turned out after he had pulled the engine apart that it was just the gas. This gas sucks.

If the car hasn't been run on a top tier fuel it's whole life, a can or two of injector cleaner can help. Plugs won't make a difference unless you have the wrong ones in there. Oxygen sensors can get lazy and start to wander over time, sometimes not enough to throw a code but enough to make the car act weird. These cars are very sensitive to battery voltage, is the car starting normally?

If I had to guess, if it knocks at part throttle but not at full throttle, it's probably not a fuel system issue or at least not a pump or regulator issue. What happens if you drive it hard for a few minutes to get everything good and hot, does the pinging get better or worse or the same?

 

I moved out here about 1.5 years ago. But it was pinging before I moved to Cali, and I was running 93 exclusively. I typically run Shell gas, or Chevron and 76.

I have had the plugs changed, before Cali, but I can't recall if the detonation started before that. I'll check the plugs.

Pinging stays the same regardless of heat.

Thanks for the help!

 

What kind of plugs?

 

I haven't checked yet, but Honda only uses oem plugs.

(I used to work for Honda Manufacturing, and it was just too convenient not to use the Service Center.)

 

Plugs will only cause detonation at part throttle if they're several heat ranges too hot. You want them hot enough so they're self cleaning but not so hot they cause preignition. Going to go out on a limb and say its much better to run too cold than too hot. I ran a heat range colder for several years (regular copper) and had no problems. With the EFI and closed loop feedback control, plug fouling is not much of a problem like it was on carbureted cars.

 

Hmmm, this is tough...I'd be thinking (in sort of this order):

Gas / plugs / O2 sensors / timing - angle sensor / fuel pump / exhaust valves (IHC, am I close?)

You may have to break down an have an experienced tech look at it.

 

Perhaps this is too obvious, but my '05 TL was knocking under full throttle. This problem was easily fixed by replacing a very dirty air filter. As you are probably an enthusiast, I doubt you have neglected your air filter, but you never know......

 

You're saying replacing an air filter cured a pinging problem? It's not possible. I'm not trying to be a jerk or calling you out but you changed something else at the same time or there's a variable you're missing. I can personally vouch that the factory air filter will go 60k without becoming a restriction and I live in a very dirty area. I don't change mine very often because the filters filter better as they age and I've measured intake restriction and there was almost no change in restriction after nearly 60k even at full throttle. There was zero change in restriction at anything under full throttle. The kind of restriction I was dealing with was not worth even 5hp.

Restricting airflow does not cause pinging. The throttlebody's sole purpose in life is the severely restrict airflow so again, if replacing the air filter fixed the problem, your car would ping like crazy at idle and ping less the more throttle you gave it since the restriction lowers with lots of throttle. What else did you do that day that you replaced the filter? I hope this doesn't come across the wrong way, it's not meant to be harsh.