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nagykaldi

Slight Engine Knock/rattle At High Speeds And Uphill

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Hi guys,

 

My 2002 Corolla CE gradually developed a slight and intermittent knock/rattle sound almost only at high speeds (60+) and upon increased load (e.g. even slightly uphill). Very rarely it happened lately at lower speeds when I had to push the car hard to merge uphill. The noise is faint and it sounds like when someone is churning a chain against a metal surface. It comes most noticeably when I push the gas pedal down just slightly when going uphill (narrow throttle). It almost goes away at wider throttles and disappears when I reach the top of the "hill". I keep the car in a really good shape, just did a 100 K service on it myself. I have 1.5 year old iridium plugs in it and run oil and injector cleaner through the engine several times a year. I did not see a significant carbon buildup last time I checked, but it is not easy to see though the plug holes. I read a lot about engine knock and carbon buildup and various removal techniques (e.g. SeaFoaming your engine). I don't agree with those who try to make the case that a knock is "normal" for any good car. It think it shouldn't be. I also read about possible pulley and belt issues that may cause similar noises, but usually at all speeds. Most of my driving is on the highway and I am quite gentle with the car. I just wanted to pick your brain before I start taking things apart. Any input is much appreciated.

 

Zsolt

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Did you notice if the "knocking" or "rattling" noise happens at a particular RPM?

 

On the 1ZZ-FE with VVTi - they do make a slight knocking noise as they pass a certain RPM point, which happens to coincide with a particular valve timing. Usually they just happen to be noticed when there is a change in engine load/speed were the VVT adjusts the timing in response. Since the noise doesn't seem to be present at low speed / light loads and lessens at higher throttle inputs - smells exactly like a VVT operation. Coupled with normal carbon buildup, enough miles on the engine, piston design, VVTi design, and the inherent noisy nature of the 1ZZ-FE engine design - can be quite noticeable in some engines.

 

There is actually a TSB on this exact issue - TSB EG009-03. Not sure if it will help - this TSB will covered under the standard powertrain warranty, outside of that period (5yr/60K miles) - it will come out of pocket.

 

Some have had good luck with replacing the little oil filter that is part of the VVT system. Usually not a maintenance item - there could be a chance that it is clogged with something that got loosened with the additives that have been added to the oil system. This would lead to reduced oil pressure to the solenoid that controls the VVT and might cause it to react slowly or not advance/retard the valve timing correctly.

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I have no codes associated with a VVTi problem. If timing is that much out so that I can hear the result, shouldn't I have a code indicating the malfunction? Can it be still a carbon deposit issue? I don't know about the RPM, but it comes almost always at highway speeds (60+) which for me is usually between 2500 and 3000 RPM. (I never rev my engine up that much, so I don't know if it's the speed or the RPM).

 

Zsolt

 

 

 

Did you notice if the "knocking" or "rattling" noise happens at a particular RPM?

 

On the 1ZZ-FE with VVTi - they do make a slight knocking noise as they pass a certain RPM point, which happens to coincide with a particular valve timing. Usually they just happen to be noticed when there is a change in engine load/speed were the VVT adjusts the timing in response. Since the noise doesn't seem to be present at low speed / light loads and lessens at higher throttle inputs - smells exactly like a VVT operation. Coupled with normal carbon buildup, enough miles on the engine, piston design, VVTi design, and the inherent noisy nature of the 1ZZ-FE engine design - can be quite noticeable in some engines.

 

There is actually a TSB on this exact issue - TSB EG009-03. Not sure if it will help - this TSB will covered under the standard powertrain warranty, outside of that period (5yr/60K miles) - it will come out of pocket.

 

Some have had good luck with replacing the little oil filter that is part of the VVT system. Usually not a maintenance item - there could be a chance that it is clogged with something that got loosened with the additives that have been added to the oil system. This would lead to reduced oil pressure to the solenoid that controls the VVT and might cause it to react slowly or not advance/retard the valve timing correctly.

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Not so much of a timing issue - just the nature of the VVTi system. Carbon deposits, especially with 100K on the clock, could be the biggest culprit here. I get the same thing on my 2002 - 150K on it right now. Runs pretty good, except for some pinging on heavy loads - but quiet everywhere else.

 

Quick test - try a tank of higher octane fuel and note the noise and fuel mileage. If the rattling, knocking is quite reduced and you may even see a slight increase in fuel economy - then I would chalk this up to carbon deposits. Might be a simple case of running the engine through its rev range a couple of times on the highway - couple of WOT apps probably couldn't hurt to help clear the plugs and loosen some of the deposits.

 

If there is no change - then I would do some more digging - I would not rule out a VVTi issue, even if there were no DTC set. The problem happening at higher RPMs (relatively speaking) should seem to point at that as a potential issue. Could be that case where the system is not quite to the point of tripping the code.

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I SeaFoam -ed my Corolla a week ago. I did have a bunch of smoke after 30 min of introducing SeaFoam through the brake booster vacuum line as directed. I actually got the spark plugs out before and after SeaFoaming and I have not seen a major effect in the engine, the cylinder looked even more covered, it received a very fine dark coating as a result of using the SeaFoam. This may result in a "smoothing" effect rather than getting rid of the stuff. I still have the intermittent rattle though.

 

Where was that small oil filter you mentioned that is connected to the VVT solenoid? How can I replace or clean that?

 

Thanks.

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Filter is on the front of the engine (exhaust side), closest to the #1 cylinder - filter can be cleaned, o-ring needs to be replaced, cannot be reused or it WILL leak. Definitely need a copy of the factory service manual or at the minimum, a Haynes/Chiltons repair manual - one of those tings that is hard to describe with words. Sometimes, a dealership will give you a copy of the FSM and a exploded view of components - when you purchase the o-ring - can't hurt to ask.

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Hi there! I removed and cleaned the VVT oil control solenoid filter. IT was almost completely clean, there was barely any dirt on it. I cleaned the contacts really good and put the screw back with the old O-ring. It did not leak at all. I also removed the solenoid itself and it looked as good as new. I still keep getting the same rattle sound right above 60 mph over 2500 rpm at light loads. The rattle seems to be actually worse now than it was before I inspected the filter and the solenoid. Any other ideas?

 

What would happen if I unplugged the solenoid for a test drive (apart from an error code or two)?

 

Zsolt

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Exactly like you said - probably just get a CEL - the engine itself will go into a "limp" home mode, so no risk of damage there.

 

Hmm. Any modifications - ie, aftermarket intake/exhaust, non-OEM sparkplugs?

What kind of engine oil are you running?

Did you try and run a some premium to see if the noise goes away or changes?

 

Another possiblity is a leaky exhaust - actually fairly common on our generation of Corolla. Can make for some unusual, intermittent rattling.

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Just a thought.....

 

Could it be the serpentine belt tensioner?? Mine had the same kind of symptoms a few years ago, made a noise that sounded like spark knock ended up being the tensioner.

 

Have not had the problem for years now.

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My dad had an 88 sentra that would ping on hills and under load when he ran 87 in it. Using a higher grade eliminated the ping. Have you tried running 89 or 93? Might be a simple solution.

Edited by brian28

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Just a thought.....

 

Could it be the serpentine belt tensioner?? Mine had the same kind of symptoms a few years ago, made a noise that sounded like spark knock ended up being the tensioner.

 

Have not had the problem for years now.

 

Totally agree. Had that problem and it's common in 2002-2003. There is even TSB, but mine was outside warranty and I did it myself. Easy $50 repair if you google for instructions. Good opportunity to replace the belt in the process.

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Of course it is not the tensioner! That would not give you noise only in a very narrow and sensitive RPM/load range now would it? That noise would be all over the map. Instead, I just pulled the plug on the VVT solenoid and voila' the noise completely disappeared. Not a tick! In fact my engine sounded like when I have first driven the car! And there was not even a significant change in pickup! Who needs VVT-i??

 

Seriously, do you guys think I can soak this thing in something to clean the inside of the mechanical part? The solenoid engages all right (hence the problem), but either at the wrong time (I hope not) or it is worn or dirty and can't deliver the full spiel.

 

Any ideas?

 

Zsolt

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Tensioners can cause problems at certain speeds / engine RPMs - just depends on what is wrong with them. Though the tensioners seemed to be more of an issue with the 9th gen than the 8th gen Corollas.

 

Disconnecting the VVT-i solenoid results in no pinging = interesting.

 

That means that either there is a heavy build up of carbon inside the combustion chambers (taper squish design is more prone to this, causes the cylinder to rock slightly within the bore), the VVT-i solenoid is smoked, the cam sprocket is damaged, or the ECM is getting incorrect sensor readings from any number of sensors (bad sensors or bad ECM).

 

Have you tried filling with premium gas and see if the noise goise away or not? If it does then I would lean toward a carbon buildup issue. Otherwise, disconnecting the solenoid would show that the car doesn't run well with a specific valve timing/overlap - that could point to many potential issues.

 

First, lets try and verify that carbon is not the major cause. This can done with regular or premium gas in the tank, though running with premium - you can knock off two items to check on your list at once. The 1ZZ-FE engine unique piston design helps with combustion efficiency, but also makes it much easier to foul up with carbon deposits at lower engine speeds. One quick way to burn these off is to run the engine at WOT at highway speeds.

 

Easiest method (highway) is to run the car at a steady 45-50MPH with O/D switched off or even in 2nd gear (4-speed automatic) of 3rd gear pulls with a standard 5-speed manual. Then punch the gas and accelerate to 60-65MPH+ (no need to go crazy, no need to risk a speeding ticket or reckless driving here), then let it coast down to 45-50MPH via engine braking. Repeat several times. This will help blow loose debris right off the tops of the pistons, and will pull enough vacuum to help clean the rings as well. Should be part of every engine break-in procedure - both of my current cars have seen this, all my cars have had this over the years and all performed well.

 

For the solenoid and VVT-i sprocket assembly - will need more equipment and time to address those. My suggestion is to take it to a well respected dealership and let them run the test on it for you - the amount of time and labor going into it will be worth the $85 diagnostic fee, IMO. They will be able to run test with a Toyota scanner - enabling and disabling the solenoid and sensor readings electronically and seeing how the car reacts.

 

As for additives, I think at this point, the engine actually sounds pretty clean - could be a case of not driving the car hard enough. Sounds kind of strange - but I've seen weirder things happen. Used to work on older GM Northstar engines, those showed similar behavior, just took them out for a couple of WOT apps - 8 out of 10 times that fixed the issue. This particular engine is also very sensitive to electrical noise - if any additional electical load was recently added, it could cause weird issues in the sensors and ECM. Poor engine/chassis grounding could also be a possibility. Also, this engine has a 10:1 compression with a very tight piston to head tolerance (taper squish) - 1ZZ-FE engine is known to be very noisy and have certain "features" like a weird stumble at 3500-4000 RPM in some cars, tapping and rattling at startup and idle, and lots of piston slap in cases of heavy carbon buildup. Lots of times, motor oil choice can minimize or aggravate this behavior. Good example is Royal Purple in the 1ZZ-FE/2ZZ-GE engine family - many have found that the engine sounds like someone poured a bunch of nuts and bolts into the engine. Can be scary sounding - but the engine oil still did its job and UOAs looked clean. I've noticed that as well - with Mobil 1 compared to Pennsoil Platinum - the Pennsoil is known to be a little thicker, engine runs well on both, but the PP quiets things down considerably (though fuel economy suffers very slightly).

 

What's the mileage and type/weight of oil you run on this engine?

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Thanks for the exhaustive explanation fishexpo! I usually take it to a small shop down the street for oil change, I assume they put the regular 5W in these cars. Royal Purple is pretty expensive! I don't think it is carbon buildup, I just SeaFoamed the car and regularly run cleaners through it. It seems OK when I look down the spark plug holes. With the VVT solenoid unplugged, the engine completely stopped rattling, and it also runs very nice and smooth at any RPM and load - not really what excessive buildup sounds like.

 

My theory is that there might be some sludge and dirt in those solenoid valve passages and they interfer with proper valve operation. This may result in bad valve timing. Again, the sound is not really like engine pinging. It is much more a rattle, like when a chain is turned and it hits the side of a metal plate. Sort of what valves could do, I guess. In any case, I will try to clean the solenoid valves first and report back. I will also try to bring myself to torture my car according to the method you suggested. Although again, you would expect a similar effect from a good SeaFoam treatment which I did.

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Yeah, really doesn't sound like a carbon buildup - especially from what you already done so far. I was just hoping for a simple problem, vs something protentially gumming up the VVT-i actuator/valve. Don't worry about the "torture" runs - won't hurt any of these engines one bit - I've seen demonstration tests of Toyota engines running on a test stand 24/7 jumping from idle to redline over a one week period - exhaust header was cherry red, engine teardown shown little to no wear.

 

Most shops have big drums of oil that they use for oil changes, some places use retail packaged quart containers - depends on the shop. The shop closest to me uses whatever they can get their hands one - sometimes its Kedall, or Pennsoil, or Mobil, or some "mystery" brand. Shops doesn't always know in some cases. For potential sludge issues, I'd suggest either running a sythetic motor oil in there (slowly cleans the engine), or some popular additives like Lucas, Rislone, MMO, and some others. Gunk engine flush works incredibly fast - but I would worry that loosening that potential sludge or deposits all at once would be more dangerous than the sludge/deposits themselves. Some have used AutoRX with good results - though I haven't tried it myself, so I can't really comment on it.

 

I also have some pics of the engine when the valvecover is off - there are some shots of the VVT-i actuator assembly in there. Don't mind the dirty looking engine - opened it up after a 14K run on snythetic oil - just wanted to see what it looked like and check clearances on the vlaves - before I changed it. Link to my photobucket site in my sig.

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