Did a search and read other threads about Accords pinging or knocking, but didn't see resolutions to issues.
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My 2011 Accord Coupe EX 4 cylinder AT w/ only 5,000 miles has developed a very slight knock or pinging upon moderate acceleration. Been noticing it for about 3 weeks. When it happens, it's in 2nd gear around 2k rpms, then 3rd gear, same rpm. It can occur for several seconds. Soon as it shifts to 4th, sound goes away. does not happen at cruise or harder acceleration.

Been using Shell 87 pump octane since January, same station. Switched stations on 11/2. Put in 3.5 gal of 76 brand 89 octane. Doing the things the owners manual suggests ... change stations or brands of gas.

still has 2/3 tank of gas. Tried to siphon gas out, but tube stops and won't go into fuel.

I know the sound of knocking or pinging, kind of like a dieseling sound when there's too much load at too low of rpms. This sounds like that. It is very slight, so slight the dealer may not hear it. I've talked to them over phone so far. I'm keeping an ear on it.

>>>> Honda sent a letter first of October - Product update - Software update to improve fuel injector and VTC timing. .... some 08-11 Accords, FI timing and VTC timing at cold start my create deposits on oil control rings .....

>>> I had the software update to Powertrain control module on 10/18/11.. OP#1255A2 .2

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I'm not 100% sure this started occuring right after the software update. I'm certain I would have noticed this much earlier since I bought car new in January.

Seems quite suspicious the S/W update might have induced this.

I know myself well enough this will continue to bother me until it's resolved. Any sounds like that cannot be good for the powertrain at all.

This stinks. One of those slight, but, to me, noticeable conditions

 

2 thoughts:

1) you're being too immediate to run a good test. 3.5 gallons of mid-grade and you expect a change?
Wait until you're down to 1/4 tank and then fill up full with 92 octane premium for the test; it's only a $1.75 more and
you want a good test to see if higher gas octane is a solution.

2) In meantime you won't be hurting your car in 300 miles. Just slight pinging sounds like.
Also, in my young and poor days I ran a compression enhanced VW (don't ask why)
for 60,000 miles pinging all the time 'cuz I put in cheapest regular gas I could find.
No problems developed and I ran it all the way to 100,000 before selling it.

 

Well if it doesn't clear up after a few fill ups I would take it in under warranty.

If you car says you can put in 87 octane then there is something else wrong. I wouldn't be a slave to higher priced gasoline.

 

Plan is to fill up with 76 brand 89 octane. I wouldn't be surprised if the gas change does not help. Next step would be to find a reliable route near the dealer where I can clearly demonstrate the noise.

 

I'm going to roll with this advice. Will switch brands to 76 which is also Top Tier gas, but will only fill up with 87 pump octane.

 

What does honda recommend for gasoline in the 2011 accord? If you are using the proper gasoline, I would take it to the dealership, so that the problem is documented early.

 

2011 Accord Coupe 4 cyl runs on 87 pump octane or higher.

Stopped by dealership yesterday. They were backed up. Ran it on the roads nearby. This will be tough because the sound is faint.

I put in 76 gas yesterday (87). Might go to dealer this morning.