Engine noise/ Power loss as engine reaches its operating temperature

[Thaik]

Hi,
I currently own a Honda Civic 2004 DX Manual and I’m experiencing a problem here.
As the engine gets warm and eventually reaches its operating temperature, I hear a knocking noise coming from the engine
from 2000-2500 RPM and it does only under load and when it’s warm.

When cold, I almost don’t hear it, the colder the engine is, the less noise you hear, there may be other noise, but it’s not knocking like when it is warm. The warmer it is, the louder you can hear it.

Also, when the noise occurs, I’m losing power, when it’s really warm, like after driving for an hour or more, the engine really feels weak and lacking power, it’s still “driveable”, but it feels like, compared to other similar vehicles, the engine isn’t behaving as it should.

Well enough talk.
Here’s a video I made:
http://www.youtube.com/watch?v=KlY6uROQ8uI (don’t know why it won’t show the link)
Paste this on youtube: /watch?v=KlY6uROQ8uI

Feedback will be very appreciated

Thank you.

Topic

[Matt]

I’m not gonna lie, that sounds pretty bad. At start-up, you have very definite valve clatter, which may be fixed by doing a valve adjustment. Eric did a video on it:

http://www.youtube.com/watch?v=P7wI4EtZSaA

There definitely is a knocking noise once the car warms up. You may want to try and pin down the area of the noise to say, the bottom end versus the top end. Was this engine every overheated or starved of oil? By starved, I mean run out of oil. It’s odd that the problem gets worse when the engine warms up. Do you have the correct engine oil in there? I THINK most Hondas use a 5w20 or even a 0w20. If you had too thick of an oil, that could have caused damage.

[ScannerDanner]

Quoted From Thaik:

Hi,
I currently own a Honda Civic 2004 DX Manual and I’m experiencing a problem here.
As the engine gets warm and eventually reaches its operating temperature, I hear a knocking noise coming from the engine
from 2000-2500 RPM and it does only under load and when it’s warm.

When cold, I almost don’t hear it, the colder the engine is, the less noise you hear, there may be other noise, but it’s not knocking like when it is warm. The warmer it is, the louder you can hear it.

Also, when the noise occurs, I’m losing power, when it’s really warm, like after driving for an hour or more, the engine really feels weak and lacking power, it’s still “driveable”, but it feels like, compared to other similar vehicles, the engine isn’t behaving as it should.

Well enough talk.
Here’s a video I made:
http://www.youtube.com/watch?v=KlY6uROQ8uI (don’t know why it won’t show the link)
Paste this on youtube: /watch?v=KlY6uROQ8uI

Feedback will be very appreciated

Thank you.

I cannot help you with where or what is causing the engine noise but your low power condition could be because of the knock sensor. It will pick up this noise and the engine computer will retard timing in an attempt to get rid of it. What this video I did on a GM with a similar complaint.
http://www.youtube.com/watch?v=vqj2YWbedsc

[college man]

is the coolant system in good order(clean flushed out) The car isn’t running hot or above normal? all fans work?

[Thaik]

First of all, thank you for all for responding
and thank you Beefy for you honesty, I appreciate it.
Well, I said it doesn’t sound that bad from a certain point of view. Because many people heard it and thought it was normal.

About the valve adjustment, we just did one last summer, and it didn’t seem to have made any difference, I think gas mileage improved a little but that’s all, knocking noise was still there. I also tried to pin point the noise, it definitely comes from the top, the engine block is totally silent.
I have to say that now the car belongs to us, it’s been very well maintained, oil level is constantly checked and replaced regularly, 5W-20 is the oil the engine is running on.
No, the car doesn’t overheat at all, which is really weird, when I say the noise gets worse, it’s not that bad, but after a long trip, the power loss and the knocking is really obvious.
Timing belt, tensionner, and water pump has been replaced and the coolant was flushed out too.

About the knocking sensor, I heard we normally get a Check Engine Light for these kind of problem, but I don’t have any! I sure would be happy if the Check Engine Light appears from time to time, at least I would have an idea about the problem, but no. It’s as if the car is pretending to be healthy when it’s not, really frustrating. Also ScannerDanner, I can’t see the link you’ve written, all I see is http://www.youtube.com, just like mine. It seems this forum is blocking links or something…
I also forgot to mention that when it’s stone cold, like once when we did the timing belt, the engine was left for two days cold, and when we started all the noises started disappearing, but when the engine picked some heat, noises started to come back all together again.

Here’s the condition of the engine:
-Engine doesn’t overheat
-Engine doesn’t burn oil (using 5W-20)
-Engine has decent fuel economy
-Engine doesn’t produce white, blue or black smoke (coming from tail pipe)
-Engine has good compression test results (around 200 psi for all cylinders)
-Engine timing has been checked and is timed (timing belt done)
-Valve adjustment has been done (0.008 for intake and 0.0010 for exhaust side)
-No check engine light has appeared since the day we have the car, and noise has been present until now(not first owner)

Considering all these, I cannot understand how the engine can be bad.

Also, I forgot to mention that engine noise/performance seems to affected by weather, on cold dry days, it runs fine, on hot humid days, it runs like crap.

Again, thank you for your feedbacks

[college man]

The only reason I asked about the coolant was I don’t know if its cylinder detonation from the cylinders getting to hot. A clogged or poorly maintained
cooling system will cause spark knock. Thats where the sensor would try to adjust the timing.C8-)also heavy carbon build up or to hot of a spark plug
can contribute to spark knock. I wonder if you bang by the sensor like scanner/danner did Then with a timing light watch the timing adjust. To prove
the knock sensor is working.

[Thaik]

Thanks!
I’m really grateful to be here, in other forums, people don’t really bother to answer even when the topic has been started a long time ago.
Sometime I just feel so fed up with the car that I want to sell it, question is, will I be able to sell it with that noise? =/

[ScannerDanner]

A knock sensor that is picking up noise (knocking) from the engine will NOT set a knock sensor code. The only time you will get a knock sensor code is when you have a sensor or wiring problem.

[Thaik]

I watched the video.
You can actually unplug a knock sensor and let the engine run without it?
I guess I will try someday, but the problem in video still seems to be originally located inside the engine.
I believe my problem is very similar to that woman’s car in the video, except that my car doesn’t drive any better at wide open throttle,
my car just doesn’t like to rev and that’s why I always shift at 3000 RPM, after that, the engine is noisy, rough, and power is there.

[ScannerDanner]

Quoted From Thaik:

I watched the video.
You can actually unplug a knock sensor and let the engine run without it?
I guess I will try someday, but the problem in video still seems to be originally located inside the engine.
I believe my problem is very similar to that woman’s car in the video, except that my car doesn’t drive any better at wide open throttle,
my car just doesn’t like to rev and that’s why I always shift at 3000 RPM, after that, the engine is noisy, rough, and power is there.

Yes you can, of course you may get a check engine light and possibly a slightly reduced timing advance curve so fuel mileage will be affected a little but at least you would be able to drive it.

[dreamer2355]

You could also use an exhaust back pressure tester or even a vacuum gauge to help diagnose an exhaust restriction.

Keep us posted.

[EricTheCarGuy]

Based on your video and description I would look for an exhaust restriction, it doesn’t sound so much like a ‘knock’ to me as it does a misfire. Try removing the O2 sensor and taking it for a drive, if the condition improves I would say you have a restricted exhaust and the most likely culprit would be the catalytic converter.

[Thaik]

Well, the funny thing is, we already replaced the exhaust manifold since it was cracked, and the catalytic converter for this car is already included with the exhaust manifold. There was no apparent difference before and after the replacement, I’m still having the same issue, sure, there is no exhaust leak now.

But I will try removing the primary oxygen sensor, if that is the one I should remove and not the secondary, and see how it runs.

I will keep you guys posted

Thanks

[college man]

keep us posted on your progressC8-)

[Thaik]

Still, this engine seems to be “knocking” quite more than the average other Civics:
http://www.youtube.com/watch?v=tKn4ublp … 8q7c2HekiA
http://www.youtube.com/watch?v=lGX-DhLS … 8q7c2HekiA

My engine doesn’t sound that nice and healthy.

[Thaik]

ScannerDanner, if I unplug the knock sensor and the car does run better, what will I be able to conclude, that the problem is indeed internal and really caused by the sensor?
But, just by hearing the knocking itself and knowing that it comes from the upper part of the engine, do you have an idea what could internally caused that knock?

Thanks

[Author]

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