EK45VTi

Hi

I have this rattling noise that I cannot identify and couple of mechanics also didn't know what is it...

So let me try to describe it...

The noise is not valve ticking or anything like that... it is more like KNOCKING SOUND but alot quieter...

You know that sound that happens when you start the car on cold winter mornings and something knocks a few seconds and then stops after oil gets to the head and valve train...

Well, this noise that I get is very very very similar to that but QUIETER...

Now, let me try to describe when it happens:

It happens between 3500-5500 rpm ONLY on-throttle

So like this... if I drive and start to easily accelerate, when engine reaches 3500rpm this noise starts (rattle) and goes away when VTEC kicks in (at least I don't hear it anymore)...

Now, if I just depress a pedal when this noise occurs, even a SLIGHT depress and the noise goes away... if I press the pedal again (even slightly) there it is again...

So another words, I can drive 3500-5500rpm's without that rattle/knocking noise if I slightly depress the pedal when it occurs...

Even a slight press on the pedal and noise comes back... the noise is there for few thousand miles (10-20)

And very important, it is very hard to get that sound when the car is not moving... if you try to rev it when in neutral, the sound WON'T BE THERE... you literally have to FLOOR IT if reving in neutral to get even a slight noise... so I guess the engine must be under load...

The engine is B16A2 from 1997. with 150.000 miles...
- mantained regularly every 5000 miles
- it does not burn oil (a quart every 3000-4000 miles)
- it doesn't smoke at all
- it pulls very well and doesnot hesitate
- it doesn't throw any CEL codes
- timing is correct and valve job is done (no change)
- VTEC kicks in every time
- oil is on the MAX on dipstick

Last week I did the regular maintenance:
- oil w/ filter
- tranny fluid
- air filter element
- fuel filter
- PS fluid
- sparkplugs
- complete OEM clutch kit w/ oil seal
- timing belt, waterpump, tensioner, thermostat and seals under pulleys
- coolant
- belts (alternator, AC and PS)
- did a valve adjustment

I thought it's either a valve lash problem or LMA (lost motion assembly) but the mechanic told me that he checked LMA's when he adjusted valves and that they are all OK... after valve job, nothing changed... valves tick a little quieter, but the "problem noise" is still here...

So please help me my friends

In my head, it has to do something with air flow...

Can valves KNOCK/RATTLE (even when adjusted)?

Please help because it gets very annoying and I like to have a top-notch engine ratlle/squeek free...

Thank you


Modified by KKVTi at 9:16 PM 4/29/2007

EK45VTi

Anyone?

csblack

Very interesting, cause I have the same thing happening to my civic. Unfortunately I cannot tell you what the RPM range is, cause I don't have a tach, but that is probably about the same range, as odd as that would be. I like you know that it is not really knocking, but does slightly sound like it. One of my jobs is at a car dealer and an old-timer mechanic told me to uses 89 octane instead of 87 and see if it made any difference. I have used it ever since I tried it a year ago, and it seems to do the trick. Now granted I know that it is not really solving the problem exactly, but apparently satisfies the engine enough to get it to stop. So you might give that a try and see if it does anything at all. As far as valves knocking even after being adjusted, its certinally possible. It all has to do with getting the right balance of air and fuel (as I am sure you know) so if for some reason it is getting messed up somewhere (maybe a sensor going bad) then it will cause knock no matter what.

EK45VTi

I tried the highr octane gas, but nothing changes...

And that noise was there BEFORE AND AFTER adjustment...

The sound can be described like this... take a screwdriver and slightly hit the engine blok with it... that's the sound...

And it's coming from the intake side of the valvetrain...

The main problem is that it is very hard to pin-point the problem because you can't really get the engine to make that noise when the car is revved in the garage... the car must be driven - the engine must be under load

I will try once again with even higher octane gas, but I doubt it will help...

Thank you for your input

EK45VTi

How does it sound when the intake manifold gasket is shot???

or if the intake mani is not tightened properly???

Rainy City

You sure it isn't your injectors? Does it sound like a diesel. You can definately hear it click on a diesel but more feint on our little gasoline engines. I had a 94 accord that made a slight ticking tapping sound and I pinpointed it to the injectors.

EK45VTi

it's not the injectors...

It0s very UNUSUAL NOISE for the engine...

Its not like valve tick, or like injectors tick...

It's very DULL RATTLE

Very similar to ROD KNOCK but a lot quieter...

And I think if I had a rod knock, I doubt that I would drive 15.000 miles... it wouldn't last 1500 miles...

And this sound is present for 15.000-20.000miles

Does not hurt performance, just ANNOYS ME!!!!!

sauceja

Get a stethoscope to try and pinpoint the noise a little closer to narrow it down. Could be worn rockers.

Otherwise tough to say without physically looking at it.

EK45VTi

well, it would be hard to use the stetoscope going 40-50mph

Like I said, it is very hard to produce that noise when the car is not moving...

the engine must be under load...

Even ih I manage to get the noise in the garage, it is very very short, not even close enough to make a pin-point...

That's why I am so frustrated cos it only happens whilel DRIVING...

So I said to myself, maybe someone had the similar case...

But let's put it this way:

Which elements on the valvetrain OR HEAD can cause noises?

- valves
- rockers
- LMA

anything else?????

instructor74

everything you describe sounds like detonation. Very light pinging but only under load and certain rpms. It can be caused by carbon build up in the combustion chamber creating hot spots and the fuel ignites before the piston is at the top of its stroke. Try having a fuel injection cleaning done then give the car a full tune up including checking the timing. You could also try to advance the timing a bit to that can help.

EK45VTi

I already did a full tune-up last week...

i don't know if there is anything fuller than this

C/P from first post

Last week I did the regular maintenance:
- oil w/ filter
- tranny fluid
- air filter element
- fuel filter
- PS fluid
- sparkplugs
- complete OEM clutch kit w/ oil seal
- timing belt, waterpump, tensioner, thermostat and seals under pulleys
- coolant
- belts (alternator, AC and PS)
- did a valve adjustment

About a sound... I don't know how a detonation sounds, but I doubt it is it... this is more like MECHANICAL NOISE... like metal-metal rattle sound but DULL

But I will try to that injection cleaning stuff

Timing is checked when valves are adjusted and it's perfect...

And I will try to play with timing a bit to see if it helps...

thanky ou

instructor74

You need to take it to a shop that has a fuel system flush machine. They will hook up to the fuel system of your car and run a cleaning agent through the engine and fuel system with the car running. This will clean the rings pistons valves injectors ect. It takes about an hour to do. then you should change the plugs and engine oil. Also If running higher octane fuel makes it go away the it is def detonation that you are hearing.

EK45VTi

Thanx...

I won't do system flush cos it is not necessary... cos when I worked on my car, I inspected everythiung and everything is clean and how it should be... valvetrain is clean, oil is clean and all cleaning the engine needs, it will get with oil...

I simply don't trust those chemicals...

All fuel system cleaning I am ready to do is put some injector cleaner...

And I am close to 100% sure that it is not detonation... cos detonation sounds completely differently... I didn't understand at first what you were talking about when you mentioned DETONATION... you meant PREDETONATION??? If it is it, I know how it sounds like and this noise is not even close to that sound

I will see what I will do...

In the meantime, if someone thinks of something, please share it

TreyDM

Lost motion assemblies

End of Discussion, go fix them

They start making noise after the 150k mark

EK45VTi

but the mechanic INSPECTED THEM and said they were fine...

And according to his words, LMA's would make noise all the time, NOT depending on how much the gas pedal is pressed or not...

But my engine makes noise ONLY WHEN the gas pedal is pushed... if I let of a gas pedal even slightly, the noise goes away...

And according to mechanic, LMA's would make noise ALL THE TIME, with pedal pressed, not pressed, every time...

I also heard a sound file of one of the guys from this forum that he recorded when he had bad LMA's and I can tell you IT IS NOT THAT SOUND...

LMA's tick very clearly...

My noise is DULL...

Unfortunately, I cannot record it...

The only way to decribe it is VERY SIMILAR TO ROD-KNOCKING SOUND but it is alot quieter than rod knock...

EK45VTi

Any ideas???