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I think you are actually supposed to use premium 93 Pump Octane gas!!
What you are describing sounds like Low Speed Knock and the best remedy is in fact shifting back so you get higher rpm. This should eliminate the pinging.
Using a lower gear will not eliminate pinging...it may make it worse...and pinging at higher RPM's is even worse.
Check the car out...I also have the same problem with my engine and I'm using 91...it should work with 91.
Originally posted by Speedster I guess I've been in the wrong gear. By not putting much load of trying to accelerate hard, it was adequate to be in 4th gear doing a lazy 3000-3300 RPM. I will try 3rd gear today, and look at changing gas stations as well.
Cheers,
Speedster
Pinging will not occur under heavy throttle...it will be worse at partial throttle situations under load as you are exhibiting....why? Because it's at this point where the car is running lean and under load...the management system is trying it's best to stay at the magic 14.7 ratio...which is the worst possible point for avoiding knocking/pinging. My car's compression ratio is 10.5 or 11 to 1..I think.
Sorry us CA Surfers only have 91 for premium. Finding anything above 91 octane is CA is like once in a blue moon. The only alternative Bay area folks have is race gas. There maybe some hidden mom and pops gas that sells higher, but its a needle in a hay stack
Our CRV is rated 86 octane minimum, and we've always used 87. However, since about 35,000 miles there is light pinging going uphill, light throttle, even though the auto tranny is in a reasonably low gearing. On a humid day it won't do it, only on a dry day.
To alleviate the problem, we use 89 octane and the noise completely goes away.
It might not be engine knock, it might be the vibration of the heat shield next to the engine. There was a thread about this in September. Go down about 33 posts to the photo of the engine compartment to see what might be causing the noise.
Or I could just repeat it here:
Yes, I now know what was/is causing the noise. On the passenger side of the engine is a black metal heat shield. It vibrates at certain engine speeds. There is a metal pin sticking out of the heater thermostat that is a bit too close and sometimes contacts the heat shield when the vibrations hit the correct frequency. I bent the shield back a bit once to mostly get rid of the sound, but it seems to have returned to its original shape and is back like before. The black paint is worn where it contacts the pin, but this is not something I spend time worrying about. It doesn't hurt anything.
My car makes the noise between 2500 and 3000 rpms with very light throttle. Let off the throttle or give it more and the sound goes away.
A 25% grade is really steep. You need to be in a lower gear with higher revs. Any car would ping under the conditions you describe. Down shifting will cure the problem and you will be putting less wear on your engine. One simple test used when going up hills if you should be in a lower gear is throttle position. If you downshift and you then need less throttle you should be in the lower gear. When towing heavy loads its the standard test in a truck. There is nothing wrong with your car, just downshift!
Holy crap, glad you posted that. While it may/may not solve the thread starter's problem, I think it will solve mine. I started noticing that ringing around 3-4000 rpm and it's only under light throttle or cruising...thought it was something in my AEM install and never got the chance to track it down. I'll have to bend the shield later today
