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Old 01-06-2008, 01:52 PM   #1
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Default Light engine knock during heavy acceleration

I'm noticing a light knocking coming from my engine during heavy acceleration. Is this normal or does this mean the engine can't handle heavy acceleration and i should drive like a grandma?
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Old 01-06-2008, 02:05 PM   #2
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What have you modified on it, if anything?
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Old 01-06-2008, 02:20 PM   #3
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Are you using Premium gas? If not, switch. That should help.
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Old 01-06-2008, 05:30 PM   #4
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Quote:
Originally Posted by vital49
What have you modified on it, if anything?
I'm curious of this too...and if you have an Aeroforce Scan Gauge or another way of monitoring KR.
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Old 01-06-2008, 05:48 PM   #5
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Quote:
Originally Posted by bonnie94ssei
Quote:
Originally Posted by vital49
What have you modified on it, if anything?
I'm curious of this too...and if you have an Aeroforce Scan Gauge or another way of monitoring KR.
i think he means that he can actually hear a "knocking" sound.

or, are you viewing live data, and picking up kr on a scanner?
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Old 01-06-2008, 08:17 PM   #6
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Quote:
Originally Posted by samueljackson
I think he means that he can actually hear a "knocking" sound.
This is correct. I can hear a light knocking sound during heavy acceleration. No mods, everything is 100% stock. I don't ever accelerate heavily (pedal to the floor) so that'* why i never noticed it. And i always use premium fuel.

*Edit* I guess it could be spark knock as the plugs and wires are in need of changing. Think that could be it? Is there a way to tell with an OBD II scanner?
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Old 01-07-2008, 12:02 AM   #7
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if the scanner has live data, then yes
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Old 01-07-2008, 08:38 AM   #8
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Quote:
Originally Posted by samueljackson
Quote:
Originally Posted by bonnie94ssei
Quote:
Originally Posted by vital49
What have you modified on it, if anything?
I'm curious of this too...and if you have an Aeroforce Scan Gauge or another way of monitoring KR.
i think he means that he can actually hear a "knocking" sound.
That'* what I meant too.
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Old 01-07-2008, 10:24 AM   #9
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Your description does sound like detonation or spark knock. I wonder if the knock sensors or the PCM they are connected to are not doing their job. They should hear that knock and retard the timing before it is loud enough for you to hear. If the sensors were covered with a thick layer of cooling system sludge, that might mask their efficiency, but that doesn't seem too likely in a car as new as yours. Are the radiator and recovery tank nice and clean?

Even if the knocking were coming from a piston pin or a rod, or some other mechanical source, the sensors should hear it and the PCM should react by retarding spark.

You can test the knock sensors with a scan tool by tapping on the block and watching for the response of the knock counter. A scan tool will also tell you if timing is being retarded, although, if it were, you would probably be able to feel it.
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Old 01-07-2008, 10:37 AM   #10
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Quote:
Originally Posted by samueljackson
Quote:
Originally Posted by bonnie94ssei
Quote:
Originally Posted by vital49
What have you modified on it, if anything?
I'm curious of this too...and if you have an Aeroforce Scan Gauge or another way of monitoring KR.
i think he means that he can actually hear a "knocking" sound.
Exactly, and if he can hear a knocking sound with his own ears I'm wondering what a knock sensor can hear. It'* just always a good idea to monitor KR whether stock or modified.
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