No big deal, I thought I would throw in a simple reply to your post. I have a ScanGauge II on the '12 TCH. I used to watch the ignition timing trying to figure out which gas it best. From my finding I could not detect any difference between 4 tanks of different top tier brands, Chevron, Shell, Phillips 66 and Texaco. I did see the ignition kick up to about 43 degrees at times.

I did find a tanker operator filling the tanks at a Texaco station. He said it's the same gas as Chevron. Actually they are the same company like Conoco/Phillips and their 76 stations.

I never used anything other than regular grade fuel. I have replaced the external gas filters around 75K miles but those were a 87 Cavalier and a 92 Cavalier. I didn't see any performance difference other then I felt better knowing it was replaced.

I eliminated some cold weather starting problems when I found I had not used the original AC brand of plugs in a Chevy. I bought champion plugs just to give em a try. That was my only change and made the car harder to start and warm up on cold mornings. I decided to go back with the original AC spark plug number. That cured my cold engine problem so from then on I only use the exact plug number that came in the engine when new. I think these new iridium plugs in the hybrids use a closer gap due to the extreme high voltages from the independent coils fired individually from the ECU.

I know engine sounds out of the ordinary or ping under sight acceleration is frustrating. I fought they with a year old '77 Olds Cutlass I had. I tried gas additives and other brands of fuel and nothing helped.

I called three different GM shop foreman and asked what did they do to clear this problem. Two told me to add water to the carb while revving the fully heated engine. It worked although I had to change oil and spark plugs after. You guessed it, a few months late it was doing the same thing. I think I mentioned earlier this was back when they first started bringing in the new no-lead gas.

You mentioning driving lots of miles in the car due to your job. Highway miles is the best way ever to clean a engine, especially if you using a top tier brand of gas.

 

Did you ever run the scan gauge and look at the timing on your old car? Not the 2012. I may have to go ahead and get one of those...

 

I used the scan gauge more on the '07 TCH I had. I don't recall the ignition details other then seeing the timing would at times advance lots higher (well over 40 degrees) than what I thought it would for a stock engine.

I still use the scan gauge II to watch the actual water temp as the engine heats up while driving away from the house on a cold winter day.

I like it's trip features which are many. My favorite is the trip mpg set to daily. It auto resets after I park the car overnight. This way I can drive to town, eat out, shop and drive the 8 miles back to our house. The scan gauge will now show me my mpg for the day. I can compare my driving speeds vs the daily weather to see if I have improved my mpg from the day before. The SC auto resets to zero anytime the car sits overnight.

The Scan Gauge's fuel setting has to be set to hybrid or the SC will shut off when your driving in the EV mode. I mounted mine on the steering column just in front of the dash/speedometer. It's nice to have the many extra readouts from the ECU. Over the six years of driving the TCH I learned to simply slow down to increase my mpg. I drive 50 to 60 highway, 38 to 40 in town does it for me. I always use the cruise.

 

I have 2006 Prius with 200k miles and has very small oil consumption. Probably only 1/2 quarts per 5000 miles with a lot 75mph cruise. It pings like nuts in the peak of summer but does less in florida winter. Coincidentally my Nissan altima 2002 with QR25DE engine also pings a lot with similar characteristic. Have changed, the colder sparkplugs, a lot of techron/PEA, MAF, etc but

LIGHT LOAD, AC ON, 30-40mph or about 1500rpm, it pings/rattles

The scanner read about 40 deg advance during the pinging. It has been pinging for more than 70k miles since I bought it used 6 years ago. Suddenly the Crankshaft position sensor died, after check and replace it with $20 sensor from Advance Autopart 40% coupon, the pinging is reduced a lot, probably only about 10% left and it is very mild only when the weather is hot and dry.

If you check the weather, during the rain, or cold cloudy humid weather, the pinging is gone because the mixture is more humid/ water in the combution chamber also absorb the heat.

 

May I ask what brand of gas do you use in the Prius and your Altima.

It sounds like your trying to doctor the real cause by using the colder spark plugs. I did the same think in a old Chevy 6-cyl Van I once had.

The oxygen sensor use to be the culprit that went out or became weak over time causing the earlier engines to act up. These newer engines have 3 or 4 sensors and just one could be your problem.

I don't know if a free Autozone scan would help if you instrument panel is not showing a fault or error code. Your scan gauge also has a error code readout if they are any.

I would sure use the correct heat range for the cold winter months. 40-degrees sounds really high under any load. My '07 and later '12 TCH both would pull the timing down to around 30 to 35 degrees when I accelerated to prevent any pinging.

I'm wondering if your knock sensors are working properly or how to test them. I think they are two on these 4-cyl engines. They sense a knock or ping should retard the timing on those two cylinders.

I don't know if the knock sensors are tested or would be shown bad with a error code or not.

I also wonder if their is a pinging TSB out on your engine but being a 2006 may be to many years old for the dealer to do any TSB updates. I don't know the rules Toyota about TSB's on older models.

The Techron should help the pinging unless their is some faulty sensor causing your problem.

I would suggest you use a www.toptiergas.com list. First watch the video then click Retailers for the list of brands.

Here used www.gasbuddy.com to choose a top-tier station with the consistent lowest price of the other top-tier brands in your city. Simply type in your zip code and press search to see your city gas prices.

Using top-tier brands of gas will keep you sensors, valves, rings and pistons clean of any deposits.

 

I used shell or top tier gas, the scanner is NDS for nissan that still can advance and retard idle timing by 2 degrees. I Tried retarding it but no different besides lower mpg. This altima indeed change the timing and at D 1500 rpm is the highest about 40 deg. It is normal based on I heard from nissan forum. Oxygen sensors are fine, I can see it directly the voltage reading during warmup and at normal temp. Practically, it is almost not pinging anymore. I do not change the sparkplugs since it does not have deposit with colder temp.

For the PRIUS I put shell gas for the last 10 tanks and 2 gumout reganes. It does not change the pinging behavior but the weather in fall helps reducing the pinging. I think it is normal because it is not KNOCKING, just pinging or dieseling noise from light throttle when the timing is advance, closed loop with enough load and air-fuel ratio close to 14/ideal combustion. If it is lean, I believe it will rattle even more.

 

You did the right thing using 10 tanks of Shell gas. Usually about 3 tanks will clear up any bad gas problems.

I think it's called a throttle body. I remember cleaning the intake on my gas only older 185k mile Corolla using a toothbrush, a lint free cloth and carb cleaner. I located mine just where the larger air intake hose comes up from the air cleaner connects to the metal fuel injection air intake. Mine had a large radiator type clamp which was easy to remove so I could clean that area.

Just inside their is a metal type plate that's controlled by a servo. I don't know the exact symptoms when these get dirty and don't work as they should. I have read these may need cleaning maybe once ever 100k miles or so.

I would recommend using Toyota/ Nippon spark plugs. I got that from a good certified hybrid tech that works at the local dealership here in town.

Since you having this pinging problem I would tend to stick with the oem toyota air filters or use the puroloator brand which years ago was making the filters for Toyota.

My other thought would be if you could have your fuel pump shop tested to see if it's putting out the correct gas pressure for you model Prius. The pump in the tank has a screen over it that can get dirty. One would think using the cleaners, Techron and etc would also clean the filter screen.

I don't know if they are any other in-line gas filters that could slow the fuel supply to the engine.

I remember a young man that bought a older Buick that pings and the engine also had low power output. He found his gas line pressure was very low. He had the pump replace and told me the old Buick then ran like new.

 

I have been waiting the campus bus for 25 minutes and watching the cars that stop and go in the 4 stops intersections. More than a half cars have similar pinging noise. It makes me believe that most car are pinging lightly to get the maximum efficiency (highest timing, close loop, 14.3 fuel-air ratio/ideal combution) and 10% alcohol just enough to touch the limit.

I do not worry anymore with my prius that reaching 200k miles today and never give me any problem. Oil consumption is low 1 quarts/5k miles and the mpg is good, power is OK, no complaint. I did changed the air filter, clean the air mass flow sensor, change the coolant, and full synthetic oil with 10k miles intervals, drain and filled ATF and laser iridium NGK sparkplugs (OEM toyota) every 100k miles.

I am sure our prius will keep going and going for another 500k miles if we maintain it.

 

Today a certified TCH tech put extra nitrogen in my tires for the winter. I ask him about pinging on over 200K hybrid engines. He said it the engine was well maintained it could be piston slap due to wear.

I also ask what if a knock sensor was bad. He said if the ECU does not receive a signal from the knock sensors the ECU will send out a error code and check engine to alert the driver.

 

Piston slap usually occurs when the engine is cold since the piston does not expand enough. If the pinging after the engine is warm in close loop, it is not piston slap. It is just at the right fuel-air mixture, advance timing, and slight pinging is normal to get the highest effeciency.

Toyota does not have piston slap issue. Many american car have one.