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My intermittent problems I’m having, are of the Pre-Ignition type.. This sound is usually of a lighter higher frequency. The sound is like splitting, or crushing marbles or small rocks. It's higher up on the engine, and is LOAD Sensitive. Or put another way, if you back off the throttle while it’s making the noise, it'll go away. My particular problem is the engine controller is giving too much ignition advance biased upon throttle position, when the engine and air temps are hot. If I vary the throttle position, it varies the timing, the load, and my 'Noise' , but this is only happening in the heat of the Summer, and for me, Only as I take off from a Stop sign or Light.

A Rod knock will go away ( depending on how bad ) if you add load (Give it throttle). Lightly loaded and fast spinning, they will KNOCK!.. A Slightly worn Rod Bearing will not knock at Idle. If the Rod Knock is severe, and the bearing is ‘Toast’, then it will just Knock, and not be load sensitive. Rod Knock is a 'Hefty' sound from lower in the engine, and if you pull the plug wire ( or how ever ) to get that cyl not to run, the sound will go away. That trick is mostly true for any of the lower cylinder related problems (not valves) .. So If you get to the injector plugs, you will be able to drop the fuel to each cyl, one at a time, and see if it's a "power train knock".. this would be pistons rods etc. This way you can tell what cylinder is the culprit.

If it’s a rod, It’ll be Number Four.. Left side of the Engine. This happens when you ( or Someone ) takes the Car for a run, and does not check the oil first. As you are setting up for that long right hand sweeper, your oil is moving to the Left side of the Oil Pan, AWAY from the Oil Pickup.. and as you start pushing out of the Corner, the engine load is increasing ( as well as the R’s ) and the Bearing Farthest away from the oil pump is now starved!.. It’s wounded.. but not totally screwed. It can be saved but will require parts and a place to work. Here is my Link to the ‘Preemptive Strike’ I did on my Spyder.
http://spyderchat.com/forums/showthread.php?30881-My-100-000-Mi-Inspection-amp-Service&highligh=
Broken piston ( unless severe ) is usually a temperature sensitive thing. Usually worse when cold, better when hot .. never quite goes away.. If it's just the piston skirt that is broken, usually no increase in oil consumption will be evident. Broken piston noise will increase with load and speed, and not 'Go Away' at higher speeds.

Bad Wrist pins will sound like a rod knock.. but a lot lighter is sound..
Bad main bearings are a load and speed related. ( like a broken piston ) usually the 'harder' the engine works the worse the sound is.. Is rare to be able to hear a main bearing knock unless it' WAY out, and usually you will have an oil pressure problem, because all the oil is leaking out the loose mains.. and the Rod Bearings will not usually survive this.

Valve train noise will be only speed related and not load related.. tend to be a 'Lighter' noise and higher up on the engine, and it's only HALF of the engine speed. Tridionally the Valves in the Spyder do not need adjusting. The wear on all the Components is ‘Balanced’ so the Clearances to not change radically over time. If you are coming up with a Valve ‘Clatter’, then something might be ‘Amiss’ in the Oil System, and Cam wear might have occurred. Or Someone has done replacement cams and not adjusted them properly in the beginning.
The Valves in the Spyder are ‘Direct Acted’ ( No rocker Arms ), and are a Pain to adjust. Adjusting requires the removal of the Cam Top Cover, then measuring AND RECORDING, the Clearance between ALL 16 ‘Bucket’s’ ( Or Pucks ), and the Cam. The Buckets come in different sizes ( Thicknesses ) that is stamped on the Bottom of them. The Buckets are then removed, and checked for the size they are is Recorded next the Corresponding Valve Clearance on your Paperwork. Then the Calculations are done to see what size buckets you need to Re-install, to get the clearances proper. After all the Buckets are moved around ( and with the Likely Addition of a few Spares from another SC Member ), the Cams are re-installed, and the Clearances are check to see how good your math was. Usually you can move the buckets around to different valves, and tighten some and loosen others, and only have to really add a few ‘New’ Buckets to the Mix.. These buckets are then saved, then offered for another Spyderchat member to use..
A problem that has plagued some of the VVTi engines, is the VVTi Actuator rattling. This Actuator is located on the Front of the Intake Cam ( Firewall side on the Spyder ), and is ‘Oil Controlled’. The Actuator is a ‘Rotary Piston Assembly’ that will change the Position of the Cam, in relation to the Timing Chain Sprocket. This way the Intake Cam Timing, can be changed to suit the Load and RPM variations the Engine will see. This Oil Controlled Actuator, is fed by an ‘Oil Control Valve’ (OCV) that is located on the Firewall Side of the Head ( Hard to get to ). This Oil Control Valve has a Contaminant Screen, that SOMETIMES gets Plugged up. This will cause the VVTi Actuator not to get Full Oil Pressure ( Volume ) while the Engine is at Lower Speeds. This Causes the Actuator to ‘Wiggle Internally’, and make a Sounds that has been referred to an ‘Idling Diesel Truck’. This Sound can sometimes be eliminated by cleaning the ‘OCV Screen’ .. Here is the Link..
http://spyderchat.com/forums/showthread.php?24305-Oil-Control-Valve-Cleaning-How-To
Another odd noise to diagnose, is the piston hitting the Head. This will happen when you have over revved and engine with week rods, or installed a thinner head gasket from the one the engine was set up for. It can tend to act like a 'Rod Knock' happening greater on the deceleration side of the rev curve, and as the engine slows it'll reduce or go away.. Unless it's just clobbering the head.. then you cant get to the key fast enough!
One Spyderchat Member accidentally had his Pistons installed Backwards during his Turbo Build. This engine had a ‘Bad Noise’ that was ‘un-diagnosable’. It was Repeatable, but seemingly not Fatal. As the Engine progressed in Miles, the Noise subsided into just another ‘Engine Noise’.. This Problem was not found until the Engine was removed and Disassembled for a change in ‘The Turbo Build’. Then it was not immediately obvious. These pistons have ‘Cut Outs’ in the tops of them for the Intake Valves to be open ( Slightly ) at piston Top Dead Center. These ‘Cut Outs’ were on the Wrong Side of the Piston as they were installed backwards. The Intake Valves were Slightly hitting the Piston Tops and had made new ‘Relief’s’ . The VVTi had something to do with the Noise not always being there at all RPM ranges. This is because the VVTi will change the Relationship of the Valve Timing to the Piston being at Top Dead Center, biased upon engine load and Speed. This shows you how good the Valves and Components are on the 1ZZ Engine.

Heat Shields.!! < Arggg>
The Worst!.. Heat Shields will kick your But!.. It’s a ‘Rattley, Tinny’ noise, that is USUALLY engine speed sensitive.. The sound is lighter than most of the other noises, and USUALLY not load sensitive.. The Heat Shields on the Pre-Cat Covers are the Likely Culprit. The ones on the Inside ( Of Course ) next to the Engine, OR the one that is welded to the Down Pipe, facing the Road, as the Pipe makes the Turn past the ‘Three Amigos’ headed for the back of the Car. If that weld Breaks ( it Will!! ) it can be ‘Snugged Up’ be using a Screw Type Hose Clamp. ( How do I know This? )..

Exhaust Leaks..
Exhaust Leaks usually sound like a Low ‘Woof, or Puff’, but can have a ‘Bite or Crack’ to the sound.. Usually Load Sensitive, as the harder the engine works, the higher the pressure ‘Puff’ in the exhaust.
My Favorite Trick to finding Exhaust Leaks, is to use a ‘Shop Vac’ hooked up to ‘Blow’. Take the hose from the Shop Vac, and Tape it to the COLD outlet of the Exhaust Pipe. When you turn on the Shop Vac ( Now a Leaf Blower ) it will pressurize the Exhaust System. You can now , at your leisure, crawl around under, over or inside of your car, Feeling for exhaust leaks, and not get burned. I have found MANY exhaust leaks that way..
Some Members have chastised me for telling people to blow krap into the engine by way of the Exhaust Pipe. Granted one Exhaust Valve will be open while you are doing this, but the corresponding intake valve will not likely be open. And if it is, it’s not by much ( Valve Overlap ).. All I can say is I’ve been doing it for a long time, and not had any problems ( That I Know of ) yet..

Hope this Helps..

Cap
 

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I'm having an issue with the "pre-ignition" symptom. I use a DASTEK chip set at Map #2 and use mid-grade fuel.

Any advice on how to treat this symptom? reset ECU? unplug DASTEK and go back to Regular fuel (don't want to)??
 

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<div class='quotetop'>QUOTE (Cap Weir @ Jun 23 2008, 03:43 PM) <{POST_SNAPBACK}></div>
My intermittent problems are of the Pre-Ignition type.. That sound us usually of a lighter higher frequency that sounds like splitting or crushing marbles or small rocks. And it's higher up on the engine. It is LOAD Sensitive.. Or put another way. If you back off the throttle it'll usually go away. My particular problem ( I surmise ) is the engine controller is giving too much ignition advance biased upon throttle position..So as I vary throttle position, it varies the timing.. and my 'Noise'[/b]
I am not an expert per say, but I'd like to point out here that it sounds like you are using the term pre-ignition incorrectly. What you are describing is "pinging" or "spark knock," which is a symptom of detonation, not pre-ignition.

Pre-ignition usually is audibly indetectable and by the time you know it occurs, the engine is usually toast. The only warning is usually a rapidly rising cylinder head temp (which snowballs the effect) and the aftermath is often a hole in your piston.

Here's a good article that discusses more than you could ever want to know on the subject http://www.streetrodstuff.com/Articles/Engine/Detonation/
 

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Discussion Starter #4
I agree.. I am using the Inaccurate Generic Term .. Pre-Ignition Ping .. it a term that most people know of..
Cap
 

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Got another one for ya.

Over the last week I developed a knock that happened when I let up on the brake. Turns out the suspension arm bushings were wearing out. Two bushings and an alignment cost me just under $300.



I chased a heat shield rattle for a year. Fixed a lot of other stuff along the way. The rattle was the plate on the bottom facing the road. Yes, a hose clamp fixed it.


Now then, how do I get the acorns out of the body panel (they came in through the side vents)? Talk about an annoying rattle...


Dave
 

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Heat Shields.!! < Arggg>
The Worst!.. Heat Shields will kick your But!.. It’s a ‘Rattley, Tinny’ noise, that is USUALLY engine speed sensitive.. The sound is lighter than most of the other noises, and USUALLY not load sensitive.. The Heat Shields on the Pre-Cat Covers are the Likely Culprit. The ones on the Inside ( Of Course ) next to the Engine, OR the one that is welded to the Down Pipe, facing the Road, as the Pipe makes the Turn past the ‘Three Amigos’ headed for the back of the Car. If that weld Breaks ( it Will!! ) it can be ‘Snugged Up’ be using a Screw Type Hose Clamp. ( How do I know This? )..
I got a couple pics of that area for anyone who needs them, they are from slightly different angles, basically jack your back end up slide under the center of the car and look up tough to miss, i saw a few questions awhile back about finding these welds, my welds finally broke, i got the pipe clamp in and it stopped the noise for the most part but i needed a bigger one, one to fit past the elbow





 

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I'm having a syncopated rattle at idle, as in absolutely no rhythm to it, I thought it would be a heat shield but this catalytic converter is new and I dont have the upper heat shield installed, the lower shield around the base of the pre-cat is still on but it doesnt sound like the noise comes from that area. ill record a video later but it sounds like its coming from the lower right hand/passenger side of the engine, around the belt area, It's done this with the 3 engines i've had in the car to the best of my knowledge. The engine is still in its break-in, and it seems to go away above 2k rpm. it could be the engine noise drowning it out. The A/C is dry, theres absolutely no fluid in it, I'm thinking that might be the culprit? will a dry compressor rattle like that at low speed?
 

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Thank you for this write up Cap. Can you offer any direction on identifying two noises I've been having?

One is a semi high pitched rattling sound. I was convinced it was a heat shield, or a dust cover over the brake rotors, but everything seems to be tight. The noise is not always present, but typically shows up under low engine speed, high engine load (commonly when I'm too lazy to downshift when going uphill). I think it may be exhaust related?

The second is a bit of a ticking noise when I'm at warm idle. The previous owner said his mechanic diagnosed it as something pertaining to the timing chain (possibly a tensioner of some sort). Does this sound reasonable, or is it more likely something else? The noise is only present at idle.

Thank you in advance for any help you can offer. Please describe things in a as much detail as possible, with as little jargon as possible. I'm not very experienced with cars (I can change oil and flat tires, but not a whole lot else).

Thanks.
 

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First post-please be kind! I did search some, but there seem to be a few different possibilities. I'm getting a sound out of the engine bay that sounds like a woodpecker tapping on metal (or that weird clicking noise the Predator aliens make). It's intermittent, but usually shows up at about 2600 and 3600 rpms. Oh, black 2001 MT, btw. 91k miles, not sure if the pre-cats have been cleaned out yet. :p

My Toyota mechanic said I had a heat shield with a broken tack weld, so I had a muffler shop reweld that up. Noise is still there. The possibilities that I've been reading about/listening to YouTube videos for include: a leaking exhaust manifold gasket, some other heat shield I'm missing somewhere, or potentially a serpentine belt tensioner. :confused:

I know I don't have a recording of the sound, but can anyone help point me towards common heat-shield rattle points? Remember, I'm used to the layout of my old '87 MkI T-top MT, so bear with me and type in big simple words. Thanks! :cool:
 

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not really a rattle, but my engine makes sort of a hissing/bearing dragging sound. Anyone know if this is common or just the sound of the 1zz-fe trying to do it's best?
 

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I'm having the same problem as you

First post-please be kind! I did search some, but there seem to be a few different possibilities. I'm getting a sound out of the engine bay that sounds like a woodpecker tapping on metal (or that weird clicking noise the Predator aliens make). It's intermittent, but usually shows up at about 2600 and 3600 rpms. Oh, black 2001 MT, btw. 91k miles, not sure if the pre-cats have been cleaned out yet. :p

My Toyota mechanic said I had a heat shield with a broken tack weld, so I had a muffler shop reweld that up. Noise is still there. The possibilities that I've been reading about/listening to YouTube videos for include: a leaking exhaust manifold gasket, some other heat shield I'm missing somewhere, or potentially a serpentine belt tensioner. :confused:

I know I don't have a recording of the sound, but can anyone help point me towards common heat-shield rattle points? Remember, I'm used to the layout of my old '87 MkI T-top MT, so bear with me and type in big simple words. Thanks! :cool:
Hey I'm just curious but did you ever solve this problem? I think I'm having the exact same issue
 

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2001 mr2

I'm having a series of weird sounds with my 1zz motor. Its all stock.
A rattling sound comes on usually between 3,200 and 3,600 rpm. And Sometimes theres a Sharp Cracking sound around 3,900 rpm. I noticed that they both go away as I press harder on the Accelerator.
The Noise only happens when I rev it up quickly or when Im giving it a low amount of throttle. HELP!
 

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Car won't start

ooo sorry wrong section
 

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I've read over Cap's original post several times now, but I'm still not sure what is causing the knocking I'm hearing. I am not at all mechanical, though. I'm hoping someone can ID what's wrong or at least narrow the list, so I can take it in and say "Look at this thing."

Here's what happened: A few weeks ago, I started the car after work and by the time I got the the exit of the garage, the check engine light started flashing and the car was violently shaking at idle. I limped into a shop a friend had recommended to me nearby, and long story short, two ignition coils had gone bad. I had them replace all four, new spark plugs and also the valve cover gasket, since it was leaking. Since it was in the shop anyway, I had them replace the struts, too; they were overdue.

When I got it back from the shop, I noticed the knocking. Took it back, and two techs couldn't hear it until I drove with one of them. He said it sounded like valve noise and added Lucas oil treatment to quiet it down. Didn't work, and it seemed to get louder. Took it to another shop specializing in foreign cars. Three techs drove it and couldn't hear it. Again, I drove one of them around and pointed it out. He said he heard it but didn't know what it was. Said to wait until it threw an engine code and bring it back.

The knocking doesn't happen when the car is in neutral, no matter how high I rev it. Even in first, it's not noticeable. But in higher gears and under load, I definitely hear it. Accelerating, going up a hill, etc.

Like I said, I know nothing about fixing cars, but I've had my MR2 since I bought it new in 2001. Best car I've ever owned and a lot of sentimental value, so I want to get whatever is wrong fixed before it does serious damage (if it hasn't already). I'm hoping someone here can help.

And if you are in Cincinnati and have a recommendation for a repair shop that knows MR2s, please let me know!

Thanks in advance for any help!

My intermittent problems I’m having, are of the Pre-Ignition type.. This sound is usually of a lighter higher frequency. The sound is like splitting, or crushing marbles or small rocks. It's higher up on the engine, and is LOAD Sensitive. Or put another way, if you back off the throttle while it’s making the noise, it'll go away. My particular problem is the engine controller is giving too much ignition advance biased upon throttle position, when the engine and air temps are hot. If I vary the throttle position, it varies the timing, the load, and my 'Noise' , but this is only happening in the heat of the Summer, and for me, Only as I take off from a Stop sign or Light.

Broken piston ( unless severe ) is usually a temperature sensitive thing. Usually worse when cold, better when hot .. never quite goes away.. If it's just the piston skirt that is broken, usually no increase in oil consumption will be evident. Broken piston noise will increase with load and speed, and not 'Go Away' at higher speeds.


Bad Wrist pins will sound like a rod knock.. but a lot lighter is sound..
Bad main bearings are a load and speed related. ( like a broken piston ) usually the 'harder' the engine works the worse the sound is.. Is rare to be able to hear a main bearing knock unless it' WAY out, and usually you will have an oil pressure problem, because all the oil is leaking out the loose mains.. and the Rod Bearings will not usually survive this.

Valve train noise will be only speed related and not load related.. tend to be a 'Lighter' noise and higher up on the engine, and it's only HALF of the engine speed. Tridionally the Valves in the Spyder do not need adjusting. The wear on all the Components is ‘Balanced’ so the Clearances to not change radically over time. If you are coming up with a Valve ‘Clatter’, then something might be ‘Amiss’ in the Oil System, and Cam wear might have occurred. Or Someone has done replacement cams and not adjusted them properly in the beginning.
The Valves in the Spyder are ‘Direct Acted’ ( No rocker Arms ), and are a Pain to adjust. Adjusting requires the removal of the Cam Top Cover, then measuring AND RECORDING, the Clearance between ALL 16 ‘Bucket’s’ ( Or Pucks ), and the Cam. The Buckets come in different sizes ( Thicknesses ) that is stamped on the Bottom of them. The Buckets are then removed, and checked for the size they are is Recorded next the Corresponding Valve Clearance on your Paperwork. Then the Calculations are done to see what size buckets you need to Re-install, to get the clearances proper. After all the Buckets are moved around ( and with the Likely Addition of a few Spares from another SC Member ), the Cams are re-installed, and the Clearances are check to see how good your math was. Usually you can move the buckets around to different valves, and tighten some and loosen others, and only have to really add a few ‘New’ Buckets to the Mix.. These buckets are then saved, then offered for another Spyderchat member to use..
A problem that has plagued some of the VVTi engines, is the VVTi Actuator rattling. This Actuator is located on the Front of the Intake Cam ( Firewall side on the Spyder ), and is ‘Oil Controlled’. The Actuator is a ‘Rotary Piston Assembly’ that will change the Position of the Cam, in relation to the Timing Chain Sprocket. This way the Intake Cam Timing, can be changed to suit the Load and RPM variations the Engine will see. This Oil Controlled Actuator, is fed by an ‘Oil Control Valve’ (OCV) that is located on the Firewall Side of the Head ( Hard to get to ). This Oil Control Valve has a Contaminant Screen, that SOMETIMES gets Plugged up. This will cause the VVTi Actuator not to get Full Oil Pressure ( Volume ) while the Engine is at Lower Speeds. This Causes the Actuator to ‘Wiggle Internally’, and make a Sounds that has been referred to an ‘Idling Diesel Truck’. This Sound can sometimes be eliminated by cleaning the ‘OCV Screen’ .. Here is the Link..
http://spyderchat.com/forums/showthread.php?24305-Oil-Control-Valve-Cleaning-How-To

Another odd noise to diagnose, is the piston hitting the Head. This will happen when you have over revved and engine with week rods, or installed a thinner head gasket from the one the engine was set up for. It can tend to act like a 'Rod Knock' happening greater on the deceleration side of the rev curve, and as the engine slows it'll reduce or go away.. Unless it's just clobbering the head.. then you cant get to the key fast enough!


Hope this Helps..

Cap
 
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