strange engine sound

[ochy38]

so i have had this sound comin from my car for the last year or so. whenever the engine is under a load, say very heavy accelerating or accelerating up a hill (not normal acceleration or "dry revving"), i get this rattling sound comin from the passenger side of the engine. i would assume a pump or the tensioner, but im just curious because its only when the engine has a load on it, i would assume a pump or the like would sound all of the time. any ideas?

[Tonglebeak]

While we're on the subject of engine rattles, I get a rattling anytime the car is 30mph or over, foot off the accelerator. I thought maybe it's my egr valve trying to fire, but I have that unhooked (harness and vacuum).

[CieraSL92]

Mine has abnormally loud fuel injector click under the conditions you describe. If that's what it is, don't worry about it. There are TSB's about this. Replace them once they go bad. It could also be spark knock, but these have knock sensors that retard the timing if that's detected. Do you notice a loss of power?

EGR's make no sound at all. Unless it's leaking vacuum, then it's a hiss.

You said it comes from the passenger side, if it's none of the above, which I suspect is is something above, then timing chain slop would be suspect. How many miles? What engine?

[ochy38]

i dont really notice any loss of power as far as i know. i will pay more attention next time it happens. btw its a 2.8 with 95 grand on the clock

[Burgundy Ciera]

Have a good mechanic listen to it it could be as serious as timing chain/guides or as minor as a pully.

[ochy38]

well i was driving it today and thinking about a better way to explain the noise.. here goes: so, you know when you are driving up a hill? ok lets say you are in 4th going up a steep hill, lets say the rpm is 2500. if i continue to press the gas, but the hill is too steep, eventually the car will shift to third. but until that point, ok, you know how the rpm will drop? (say i i press the gas, and the rpm is dropping right before it decides to shift), if i press the gas in the noise will start, but only when the accelerator is at a certain point. the noise correlates with me pressing down the accelerator, not the rpm. but its strange because it doesn't happen unless the engine is under a load, which is why the fuel injector problem sounds both probable, but at the same time strange, to me.

[CieraSL92]

Can you compare it to a noise we are familar with? Like marbles in a can, the sound of birds chirping etc.

[Tuddi]

Can you compare it to a noise we are familar with? Like marbles in a can, the sound of birds chirping etc.

Or like a mother-in-law pretending to be nice, or sounding like your ex-mother-in-law the first time she saw you with your new gf.... :D

I'm sorry, couldn't help myself ....

[ochy38]

lol

sounds kinda like marbles in a can, imagine this: think of how popcorn sounds when your cooking it, if it was in a metal container, and instead of being popcorn it was ball bearings, kidna like that lol. idk its hard to explain.

[CieraSL92]

That makes me think the timing chain. Do this for no longer than two minutes, since the water pump will cause it to overheat, but not terribly quickly. Take off the belt and try to reproduce the problem. If it goes away, its one of the belt driven acc. If not, timing chain or some random loose bolt rattling. Do not run the engine longer than nessecary since it will overheat and you'll have to deal with more problems than a rattle.

[ochy38]

alright ill give it a shot sometime when i have time

[85_Ciera_Rebuild]

well i was driving it today and thinking about a better way to explain the noise.


EGR Valve (or clogged passage way).

Ping Sensor In-op....

[85_Ciera_Rebuild]

That makes me think the timing chain.


At less than 100,000 miles...no...more like Ping Sensor or EGR Circuit.


Ping Sensor is on FireWall side on 2.8 motor...if you could tap on block near it when engine is idling, you might be able to see if it works...engine RPM will change...at least on SBC it does.

I wonder if any trouble codes exist.

[ochy38]

could it really be the egr valve if there is no hesitation in the engine? also, the ping sensor, where on the firewall side of the engine is it

[85_Ciera_Rebuild]

could it really be the egr valve if there is no hesitation in the engine? also, the ping sensor, where on the firewall side of the engine is it

EGR is not related to hesitation, in the sense you might experience....function of EGR is to cool down combustion chamber...with extra heat there, you get pinging under acceleration.

If you have 2.8/3.1 motor...Knock sensor is right hand side of block (firewall side), below the exhaust headers...it is larger and round in shape with a single wire (think)...it has a heat shield on top of it.

Diagnosing Digital EGR Valves
(http://www.wellsmfgcorp.com/pdf/Counterpoint3_4.pdf)

Off hand...it points to your Knock sensor...if you can tap gently with a hammer near this sensor while engine is running, the engine RPM should change.

[centurycoupe]

sounds like harmonic balancer,mine made that "bearings in a can sound"only at a certain rpm.

[ochy38]

yea but the problem is it isnt related whatsoever to rpm.. just throttle position. say im at 1500 rpms and coasting, there is nothing. but if im in overdrive and press the pedal in, the rpms are at 1500 and because it hasnt downshifted yet it isnt a getting any higher, the noise comes in.

[85_Ciera_Rebuild]

the noise comes in.

Knock Sensor

Question: 2001 Chevrolet Impala mileage: 84,000 (http://www.2carpros.com/topics/knocks.htm). I've got a knocking problem with my car that is driving me nuts. The knocking occurs when about 1/3 to 1/2 of the throttle is engaged. I've tried different brands of fuel, different grades of fuel, replaced the EGR, and run 2 bottles of complete fuel system cleaner with little results. The fuel system cleaner helped some, but the knock is still exists. When I mash the throttle and downshift, the knock ceases. Under almost no engine load, there is no knock. Under high Rpms and engine load, the knock ceases to exist, probably because my ECU doesn't look for EGR at wide-open throttle. I do not suspect a fuel delivery problem because I plenty of power at high load/RPM. I do not suspect an ignition problem either because I've been told that if my opti-spark is bad, I'd have lots of problems at high Rpms, which I don't. I'm frustrated at this point because when my engine knocks. The check engine light is not on. I'm afraid that eventually I'm going to damage something. Can you shed some light on this mystery knock problem?

Answer: Change the knock sensor. What happens is the sensor as far as the PCM is ok but in reality the knock sensor has lost its ability to detect minor knocks and only sees the larger one therefore not triggering the" Check Engine" lamp.

[85_Ciera_Rebuild]

92 Buick Regal knock sensor location?
(http://answers.yahoo.com/question/index?qid=20070918164625AA1KKsm)
Hello, I am trying to locate the Knock sensor on my 92 Buick Regal GS, It has the 3800 engine. I know they are commonly on the rear of the engine near a cylinder or water jacket but I cant seem to find it. Any one know?
Thanks in advance

Best Answer - Chosen By Voters

I own a shop, and think this: The knock sensor is located in the engine block, one under the right bank cylinder head, and one under the left bank cylinder head. Yours may only have one, and if it is it will be on the passenger side or right bank. To control "Spark Knock", the knock control system detects "abnormal vibration" in the engine. This system is designed to reduce spark knock up to 10 degrees during periods of heavy detonation. This allows the engine to use maximum spark advance to improve driveability. The knock sensor produces an AC output voltage which increases with the severity of the knock. The signal is fed to the (computer) PCM and the timing is retarded up to 10 degrees to compensate for the severe detonation. Any problem with the knock sensor circuit will set a code 43. Spark knock is not the only thing that will set the code. A bad timing chain is a common problem that causes the timing to go out far enough to cause severe detonation. Most any knock in the engine will do this. You must look down both sides of the block just below the heads for the sensors. Hard to find? Yes! Hard to get to? Yes! Check: Disconnect the electrical connector for the knock sensor and with the ignition key on (engine not running), check the reference voltage from the computer using a voltmeter. It sould be approximately 5.0 volts. Now, check the resistance of the sensor (connector disconnected) using an ohmmeter, it should be approximately 8,200 ohms. If the knock sensor resistance is correct, but there is no reference volatge available, then check the wiring back to the computer, and suspect the computer as the problem. If you can get to it, you can check the sensor by banging on the block with a long extension, or hammer near the sensor (with engine running) and the engine should stumble as you do it, as this should cause a change in the ignition timing.
Glad to help out, Good Luck!!!

[ochy38]

hey thanks for the info.. now i just gotta decide what im gonna do lol

[85_Ciera_Rebuild]

...what im gonna do lol

1. Timing Chain - Might remove belt and see how much it turns...

2. Knock Sensor - Instructions here above - 92 Buick Regal knock sensor location?