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Discussion Starter · #1 ·
For a while now, I've heard what I believe to be pinging under lower rpm acceleration especially on warm days. I asked the independent Honda/Acura shop where I get my oil changed about it. He took it for a ride and thought he heard it a little but couldn't tell for sure. It was a cool morning (mid 60's) and I didn't hear it when I left either. He asked what gas I used and I told him Mobil and Chevron 91 octane. He said that was good, to avoid Arco and no-name stations, and suggested running a couple of bottles of Techron through it. While Chevron gas does contain Techron, its so diluted as to be almost useless. He also said that Techron is the ONLY fuel or oil additive recommended by Honda. My engine might have some carbon deposits that might be enough to push the compression too high on warmer days. So I've got a couple of bottles of Techron in the trunk waiting for the next fill up. I'll keep you posted.
 

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Discussion Starter · #2 ·
Update:

Burned just over 2/3 tank with a 12oz bottle of Techron in it. The weather has been in the 70's. DAMN! All of a sudden it feels way more powerful. Quieter too. I can lug it up a hill in 5th at 40mph with much less pinging than before. Shifting also feels smoother. That's the first thing I noticed. Its like the engine can better handle the sudden jump in load when the next higer gear engages. Feels like a new car. We've got some hotter weather coming up so it should be a good test. Can't wait to see how it runs after the 2nd bottle.
 

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Hmm - how many miles do you have on your CL?

And I wonder if the non-CA-crap-gas we get here is better on deposits, etc?
 

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mdaniel said:
I have 38k but have had the problem for a long time. Mark had the same problem in AZ.
And it's gone, just like that?! :dunno:
 

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Excuse me for sounding like a dummy, but what does 'pinging' mean?
 

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Iridium130 said:
Excuse me for sounding like a dummy, but what does 'pinging' mean?
Pinging happens when your engine "predetonates" - when the cylinder gets so hot that it explodes the air-fuel mix BEFORE the spark fires. Here's a link I found on timing adjustments that has some good info on predetonation:

http://www.geocities.com/bayourovers/trick19.html

Specifically the following exerpt:

"First, a bit of theory. Ignition timing is important because it is the spark from the spark plugs that causes the fuel to combust, giving force to the piston, which in turn gives revolution to the crankshaft, which through a series of gears makes you go down the road. If that spark occurs at the wrong time, you loose power. Usually the spark should occur a bit prior to the piston being at the top of it's stroke. Like a hunter leading a duck, you want the maximum explosion to occur as the piston reaches it's pinacle. If it occurs to early, the exploding fuel tries to push down a piston that is on it's way up. If it occurs to late, the force is lost on a piston already on it's way down.

The other factor that comes into play is fuel quality. Higher octane fuel is less combustible at a given pressure. This allows timing to be set farther in advance, giving good power at high RPM's. This is drag racing stuff. Octane of 85-90 is fine for the 2.25 engine, anything more is a waste of money. Higher octane fuel does NOT burn cleaner. In fact the lowest octane that you can run on places less stress on your engine, but it will be more prone to preignition. Preignition occurs when the fuel/air mixture in the cylinder ignites prior to the spark plug firing. This can be caused by sharp edges in the combustion chamber, carbon build up, low octane gasoline, or other factors. It manifests as a rattling noise when the engine is under load, often called pinging. Preignition is bad. It wears an engine out quickly, can damage piston heads, rings, valves, etc... "
 

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Discussion Starter · #8 ·
mffdvr said:

And it's gone, just like that?! :dunno:
Not quite. The problem was worse on hotter days and its been cool here. It makes sense that I'd see improvement first on cooler days. The first thing I noticed was the smoother shifts. Then the next day it felt like it had more power. Maybe it works on the deposits then suddenly "breaks through" and they go out the pipe. I just dropped in my 2nd bottle tonight. Should be interesting. Oh, and its shifting at redline like it used to too.
 

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That story = Too sweet!!

:bigok:
 

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Discussion Starter · #10 ·
Alright. Now the bad news. My car is running so great I can't stay off the gas any my mileage is sucking harder than usual. Too bad I didn't dyno it before the treatment because I'd really like to know how much power I was losing. Any stock CL's with 30-40k miles and want to send me a graph?
 
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