Cleaning carbon deposits

I don't care for your confrontational attitude........again.

The point IS that what you are trying to "fix" is the stuck rings......if that is the cause.
If it is because of worn out rings, none of that will do any good......and might actually make matters worse.

Trying to "fix" carbon build-up simply be removing the carbon is a fools errand.

Actually I have no problem with directly treating the rings to SEE if it will help or not.
I did an "intake feed" with MMO on an old pickup years ago with remarkable results.
I don't know if it also had "carbon buildup" or not; didn't care.

What I have a problem with is twofold:
1) Putting "crap" into your oil hoping for a miracle cure that almost NEVER happens
2) Treating carbon buildup just for the sake of getting rid of the carbon......when there is no evidence that it is really causing any trouble.

 

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What about when the engine is warmed up and at high RPM: what unusual engine sounds if any do you hear? Does this knocking sound occur only when the engine is warmed up and at idle speed?

 

I have a question to ask Patrick Wong. I have a 2011 Prius Two that I bought new 3 years ago. About 2 years ago my wife and I departed on a trip. After about 2 1/2 hours into the trip I smelled a very bad odor. I discovered my wife had laid a light jacket on the back seat which blocked the vent for the hybrid batteries. When I removed the jacket the odor from the batteries almost immediately disappeared. I have had no problems as a result of this incident. My question is this. Do you think this overheating of the hybrid batteries might possibly cause the batteries to have a shorter than normal lifespan?

 

Since this happened two years ago, was a one-time event, and you have not had any driveability issues since then, I think your traction battery is and will remain fine.

 

Thanks Patrick. I appreciate your opinion.

 

If the knocking sound only occurs at low speed RPM then it is not likely that any mechanical part is actually broken.

Using Mini VCI, I would suggest you look at the engine ignition timing at the RPM where the engine knocks. Compare to ignition timing at the lowest RPM where the engine sound is normal. Maybe the spark timing is too advanced, causing the knocking.

The engine has a knock sensor which is monitored by the engine ECU. The ECU is supposed to retard ignition timing as necessary to prevent knocking. DTC P0325, P0327 and P0328 are related to that circuit. I haven't noticed anyone complaining about having problems with those DTC.

Also you might try refueling with 91 octane premium unleaded fuel when you've used up the current tank. Just add 4 gallons as an experiment, and see if that makes any difference to the knocking issue.

 

Would you mind uploading a recording to youtube?

A lot of things can sound like engine knock including bad belt, pulley, or tensioner. I had that problem in subaru and corolla.

Mechanic's stethoscope should be your friend.

Mechanic's Stethoscope

 

Also, pls remind us of the model year and odometer reading of the car with this problem, since you own too many Prius for us to keep track of...

 

Congrats on the purchase, you worked hard to make the transaxle swap a success so it is reasonable for you to buy the car and get some value out of it.

Guess you need to update your signature block... I hope you are keeping battery tenders or battery chargers on all of the 12V batteries in your Prius fleet.