Is your 8 having issues with vibration at idle?

I had a new right (passenger-side) engine mount installed on my car today. I was told by the mechanic at my dealership that there is a known issue with this mount that a tech support bulletin had recently been released on. He said according to the notice it was affecting cars at approximately 18,000 to 25,000 miles and was caused on the passenger side only because of the close proximity of the mount to the exhaust ports on that side of the engine. The problem can be seen if you remove the wheel and pull back the rubber splash gaurd and inspect the top portion of the engine mount for cracks. If you have the problem you would notice the car vibrating at idle. The problem was not noticeable once you have the car above 1500 RPM and where moving. The new part number for the updated mount is F151-39-040C. The original was 39-040.

That's interesting. I have a vibration problem at idle that is very annoying, especially when the A/C compressor kicks on. I don't see a TSB posted for it yet, so thanks for the heads-up. I'm taking my car in soon, and now I have one more thing they can check. How's your vibration problem since the mount was replaced? Mine is always worse after the car has been running a long time.

There is a new mount..with varied results.

The new one has a heat shield to protect the mount from the exhaust.

If your vibration is more noticable now then when you bought the car this may be for you.

Well, I pulled my wheel to try to look at the engine mount. I could not pry the boot up with a screwdriver - it was almost like it was glued, and I didn't want to be accused of 'ruining it' by the dealership. Anyway, watching the mount with a flashlight during idle, I was getting about 1/8" of travel. I didn't jack up the driver's side to see if it was the same, but I'm betting it's not.

interesting. I don't see a tsb on finishline performance, but this is good to know. Maybe snap on has more info? Atl8 has this helped?

there is no tsb but there is an "mri" its one step below a tsb. what snap-on said is abouty all there is to know. some vibrations have been found to be caused by a broken motor mount. the new version has a heat shield.

Is your 8 having issues with vibration at idle?

I had a new right (passenger-side) engine mount installed on my car today. I was told by the mechanic at my dealership that there is a known issue with this mount that a tech support bulletin had recently been released on. He said according to the notice it was affecting cars at approximately 18,000 to 25,000 miles and was caused on the passenger side only because of the close proximity of the mount to the exhaust ports on that side of the engine. The problem can be seen if you remove the wheel and pull back the rubber splash gaurd and inspect the top portion of the engine mount for cracks. If you have the problem you would notice the car vibrating at idle. The problem was not noticeable once you have the car above 1500 RPM and where moving. The new part number for the updated mount is F151-39-040C. The original was 39-040.

Glad my buds were able to help out! Wording gets it done everytime. Mines over there right now getting all the goods.

Charlie

out of curiousity, I took my right wheel off and checked the mount as best I could. I fired up the car and watched and I didn't see anything that looked like a crack, and while I could feel the vibration, it wasn't huge. I did find it interesting that the subframe where the mount is attached didn't seem to vibrate at all, yet the brake caliper on the wheel you could feel the vibration from the engine. I'm guessing that the subframe is mounted in such a way that its to stiff to move much, while the wheel and brakes would be the exact opposite.

The little rubber splash guard atl8 is refering too is not on the engine mount, it hangs vertically near the brake lines. The cracks would be visible on the mount without moving anything.

The little rubber splash guard atl8 is refering too is not on the engine mount, it hangs vertically near the brake lines. The cracks would be visible on the mount without moving anything.
.....not that I am freaking out or anything, just out of plain curiosity....would anyone have a photo of where to look. Yes...I know :o but I am a very graphic oriented person. :p

Yeah, a photo would be great.
I'm wondering if a heat shield could be installed to the original motor mount to prevent it from cracking...

Thanks need to go out to Charlie (Marietta8) for informing me about this and other issues that need to be updated when I was at his shop the other day. I dropped my car off yesterday to have this procedure done with hopes of getting it back today but we will see. I guess it is a pretty big issue they are having because the sevice manager told me that Mazda was sending them the motor mounts via fedex overnight which is not very common.

Thanks need to go out to Charlie (Marietta8) for informing me about this and other issues that need to be updated when I was at his shop the other day. I dropped my car off yesterday to have this procedure done with hopes of getting it back today but we will see. I guess it is a pretty big issue they are having because the sevice manager told me that Mazda was sending them the motor mounts via fedex overnight which is not very common.
It's not that uncommon for the dealers to order overnight delivery of parts. When I need parts that are not in stock, they always ask if I need it tomorrow.

pictures as requested. one w/ splash shield on, 2nd with it pulled away. 3rd is a not quite focused close-up. The piece with the yellow dot is the new heat shield.

What I've noticed with the mount replaced is no more vibration felt by my hands on the steering wheel. Before the car would shudder every 10-15 seconds or so and I'd notice it there.

pictures as requested. one w/ splash shield on, 2nd with it pulled away. 3rd is a not quite focused close-up. The piece with the yellow dot is the new heat shield.

What I've noticed with the mount replaced is no more vibration felt by my hands on the steering wheel. Before the car would shudder every 10-15 seconds or so and I'd notice it there.
Hats-off to you!

Interesting... that doesn't really look like a heat shield but like a bracket or clamp to make it tight.

Ya know. Methinks Tamas is correct. I just jacked up the driver side on my car and inspected it's motor mount and it looks exactly the same as the new one that was just installed. I even crawled underneath the car and looked at the new mount from the engine side. I don't see anything that looks like a heat shield to me. Also, the mechanic at Mazda didn't mention it had that, someone in this thread said that and I ASSumed it was the case. Regardless, it has helped with the vibration I was experiencing at idle, and for that I need to thank Charlie at Mazcare for pointing me to someone that was really helpful at my dealership's service department.

I have been having the exact problem and been driving 2 of my local dealers nuts with it! just so happens my car is there today so I just called them to check that out for me and they had absolutly no clue or info about the issue. They are going to check it anyway, but at least they won't tell me it's just the computer" breakin in" anymore! I will repost when I get the car back tonight, But awesome info....Thanks :D

My 9/30/03 build engine mount looks just like the one in your picture, except I have more than one yellow dot. I'm still gonne try to get it replaced on my next service.

Just got an answer back from my dealer today, and they confirmed that my passenger side mount is cracked!!! This rough idle/vibration thing has been driving me nuts, I have had the same symptoms as everyone else in this thread and the dealer kept telling me it will smooth out when the computer breaks in????
The big difference on my 8 is that it only has 7,000 miles on it. :eek:

Just as a tip to everyone else, if you have a rough idle/vibration tell your dealer about this, because as in my case they had no clue and were very curiuos as to how I even knew about it!
Big thanks to atl8, snap-on and all else on this thread, you have saved me from trading back my beloved 8 :D

my '05 came with the new motor mounts installed

bump

The parts system shows the mounts have been modified 3 times.

F151-39-040C (HP)
F151-39-050C (SP)

The latest mount should have a heat shield to protect the rubber from the exhaust heat.

I sat in a 05 and let it warm up, I could feel the vibration, just not as much as mine. I wonder if that car had these mounts, I would guess not, prolly one of them in between the original and this new design.

Without the build date it would be had to tell. The new mount shows the latest revision in Jan 05.

VIN: JM1FE173150151406 - Thats what I tested

I have a simular issue. My steering wheel doesn't vibrate, but the car makes a rattle noise at idle whrn the a/c is on. I don't hear it from inside. When I pull up to a inclosed place where noise can eco, I can really hear it. I'm taking mine in tomorrow to see if I can get this fixed. It sounds like this could be the same problem.

Without the build date it would be had to tell. The new mount shows the latest revision in Jan 05.


mine is 12/04, I don't have any idle vibration issue, I would tend to believe these parts would go into production vehicles before TSB service

Hmm, very interesting, a durability issue with the mounts. The fact that Mazda released a new part with a heat shield indicates that engineering screwed this one up. Sounds to me like Mazda needs to add some requirements their mount design specifications.

I don't think my car has a failed mount. Every car vibrates to some extent while the engine is running. If the vibration feels severe, you should have the mount checked out. If it doesn't feel severe, please accept the fact that it is normal and save Mazda the warranty cost.

The new one has a heat shield to protect the mount from the exhaust.

If your vibration is more noticable now then when you bought the car this may be for you.


Great!!
This can't be good for Greddy turbo owners. Bought my car in Jan '04 and I mine has 3 dots on it. I haven't had a noticeable vibration at idle, yet. As you can see from one of my install pics, that turbo is adding alot more heat to that area and could present problems over time.
Anyone have a price on the new design ones, just in case.

About 100 bucks..

I wonder if someone can make a heatshield better than the factory one?

It shouldn't be too tough to fabricate.

I dropped my car off today for the new part as I was heading out on vacation, so we'll see how it works when I get back in from D.C. on Sunday.

My 8 has 17711 miles on it.. so I'm pretty close to the 18k threshold listed in the original post.

I bought the car used w/ about 16200 miles on it. I've noticed that sitting at a stop light or whatever (especially w/ the A/C and/or defroster on) the 6 speed MT stick vibrates something aweful. The idle according to the tac is rock solid at just under 1k. Ever once and a while it feels like the whole car shudders.. but it's mostly in the stick.

Are these the symptoms of the broken motor mount? (It's raining outside, or I'd attempt to pull the splash guard back and take a picture..)

My 8 has 17711 miles on it.. so I'm pretty close to the 18k threshold listed in the original post.

I bought the car used w/ about 16200 miles on it. I've noticed that sitting at a stop light or whatever (especially w/ the A/C and/or defroster on) the 6 speed MT stick vibrates something aweful. The idle according to the tac is rock solid at just under 1k. Ever once and a while it feels like the whole car shudders.. but it's mostly in the stick.

Are these the symptoms of the broken motor mount? (It's raining outside, or I'd attempt to pull the splash guard back and take a picture..)Absolutely not. The shifter mechanism is directly attached to the transmission, so it's always going to vibrate quite a bit. The occasional vehicle shudder at idle is also normal. This is caused by sudden drops in engine speed that cause high amplitude vibration of the engine on its mounts, some of which is transmitted to the body. The tachometer in the instrument cluster measures only average engine speed. In actuality, the instantaneous idle speed of the engine fluctuates around +/- 30 rpm of average speed. The sudden "dips" in speed are not picked up by the tach in the instrument cluster.

Ok, then I'm confused from reading the description of the problem.. what are the symptoms of a "rough idle" then?

For what it's worth fray, my car has done 15000 miles and my shifter NEVER moves more than 1/8" at idle. A 1/16" in movement is average.

I have a different PCM calibration to you though.

Gomez.

do you like get a ruler out and hold it next to your shifter, film its movement, upload it to your computer, then slow it down to see how much its moving?!?

I don't need to. It moves SFA...and SFA is about 1/16".

i feel really dumb...whats SFA?

Sweet F*** All.

oh, right, i knew that >.>

Displacement is only one measure of vibration, and not the best. Displacement can be small while dynamic velocity and acceleration are high, depending on the frequency components of the vibration. When you touch the shifter lightly you're always going to feel vibration. It is not a sympton of rough idle.

A sympton of rough idle is excessive shake or vibration felt in the seat, floorpan, and entire vehicle body. However, as I mentioned before, even a car with perfectly fine engine mounts may occassionally have periods of rough idle, due to sudden drops in engine speed which create engine movement that can't be fully isolated by the mounts.

Just an FYI, I inspected the motor mounts on my 8 (17k miles, 05/03 build date). There are three yellow dots on it.. but as far as I can tell no cracks.

I have pictures of the mount if anyone cares.

So speaking of the cracks where are they present? At the weld of the two support posts and the metal ring?

Has anyone made solid aluminum/other type of mounts for these cars yet? For everything, motor and drivetrain?

I put solid aluminum motor/tranny mounts on my 2nd gen rx7, and solid steel front differential mount with solid delrin rear differential mounts and am much happier with them. Some people don't find the motor/tranny mounts to be streetable since you can get vibration at higher speeds and in 5th gear, but you'll most likely never break them. When I went to replace my mounts I had both tranny mounts cracked and one motor mount broken completely in half. For me it's just for piece of mind and I was curious if this had been done for the rx8 yet.

Has anyone made solid aluminum/other type of mounts for these cars yet? For everything, motor and drivetrain?

I put solid aluminum motor/tranny mounts on my 2nd gen rx7, and solid steel front differential mount with solid delrin rear differential mounts and am much happier with them. Some people don't find the motor/tranny mounts to be streetable since you can get vibration at higher speeds and in 5th gear, but you'll most likely never break them. When I went to replace my mounts I had both tranny mounts cracked and one motor mount broken completely in half. For me it's just for piece of mind and I was curious if this had been done for the rx8 yet.Hehe, would definitely not recommend solid metal engine mounts for a daily driver, unless you don't mind drastic increases in vibration and interior noise levels. Some people really don't care, others would be horrified at the results.

yeah true buckeye, for a weekend car it would be much safer, but it would probably drive you nuts as a daily driver

yeah true buckeye, for a weekend car it would be much safer, but it would probably drive you nuts as a daily driverThe primary reason someone would go to a solid engine mount is to handle the increased loads from an engine with major horsepower/torque upgrades, or if someone takes the car to a track a lot. The stiffer the engine mount, the less the dynamics of the car are negatively affected by the engine bouncing, rolling, and pitching on its mounts. The added safety/reliability is really an afterthought.

Absolutely not. The shifter mechanism is directly attached to the transmission, so it's always going to vibrate quite a bit. The occasional vehicle shudder at idle is also normal. This is caused by sudden drops in engine speed that cause high amplitude vibration of the engine on its mounts, some of which is transmitted to the body. The tachometer in the instrument cluster measures only average engine speed. In actuality, the instantaneous idle speed of the engine fluctuates around +/- 30 rpm of average speed. The sudden "dips" in speed are not picked up by the tach in the instrument cluster.

>>>>I have had this issue myself. Been to 3 different mazda dealers, 3 times each and have not had any resolution found. Theyy have only tried fuel injector cleaner and reflashing my PCM to "P" (which we all know has nothing to do with rough idle). The thing is, I seem to have noticed it as soon as my engine flooded in January.

>>>>>Only at a stop. I get a consistant vibration, that goes in and out about 8 seconds apart. Constant vibration is experienced when opening a window or the sunroof though. None while moving and RPMs are constant, no fluctuation.

>>>>>So this is normal then?

>>>>>Only at a stop. I get a consistant vibration, that goes in and out about 8 seconds apart. Constant vibration is experienced when opening a window or the sunroof though. None while moving and RPMs are constant, no fluctuation.
If you are saying that whenever you put an electrical load on the system at idle the car idle drops and you get increased vibration, then you may want to replace the battery with a more capable one like the Mazda recommended replacement, the Interstate MTP-35. The OEM battery is not up to the task.

If you are saying that whenever you put an electrical load on the system at idle the car idle drops and you get increased vibration, then you may want to replace the battery with a more capable one like the Mazda recommended replacement, the Interstate MTP-35. The OEM battery is not up to the task.

They already did, a month ago. The vibration increase is not severe, just noticable. Would that still be an issue?

My mount was just replaced, and my vibration went from obnoxious to moderately irritating :)

i have this problem too. consulted my mech, he claim that by changing the mount will not solve the vibration. it might be due to other factors. changing the mount will cost ard 400. if it does not solve the prob its not money well spend. he recommend a full diagnose at 120. any comments?

i have this problem too. consulted my mech, he claim that by changing the mount will not solve the vibration. it might be due to other factors. changing the mount will cost ard 400. if it does not solve the prob its not money well spend. he recommend a full diagnose at 120. any comments?If your idle vibration is severe, the tech is obligated to check the mount for damage. If the mount looks fine, then there's no reason to replace it. If it's cracked, warranty will cover replacement and it WILL improve your idle vibration. You should not pay for a full diagnosis at $120 until he at least visually inspects your mount!

The engine mounts on the RX-8 are OIL filled so they act kind of like a hydraulic damper.If the rubber 'cracks' you will observe oil run out.I have not seen a leaking mount on an RX-8 yet but I have seen one on a Mazda3.Oil is very obvious,so if you don't see oil there is unlikely to be a problem with the mount.

i've had the same vibrating issues. my car was in an accident so that probably contributed to damaged mounts. i brought it to the dealer and they replaced both left and right engine mounts under warranty and the vibration was gone. it actually felt like i was driving a brand new rx8 again. smoooooooooooth.

The part numbers have changed again. Have the dealer call the tech line for the latest and greatest.

I think the rough idle is only ok when your car is tuned with a Turbo or SC. I dont think its normal when your car is stock. Something is wrong with the idle from the re-flash program. My 8 never had this rough idle untill I got flashed like over 10 times.

My car has had a rough idle since new, but is worse since the latest flash in June. I commented on it when I picked up the car, but the mechanic had no explanation. I checked the motor mount last night, and it looks fine. I'm going to call the dealer to see if they have another idea. The latest flash is great except for the idle. The soot in the exhaust pipes is almost gone, more power, gas mileage has improved about 1 mpg. If they straighten out the vibration at idle, the car will be fantastic.

I had the problem with my car vibrating way too much at idle. I have an automatic, not manual. I took it in for service today and they fixed it up with no problem. They replaced the motor mounts and the receipt said that the old ones were "distorted". I was glad they had the parts in stock so I didn't have to wait for them.

.. If they straighten out the vibration at idle, the car will be fantastic.

When I first got my car (July '03) I had absolutely NO vibration - since all these flashes the shifter always has some vibration and will rock 'n roll some at a red light!
Bugs the heck outta me.

I think we're talking about the whole car, nut just the shift knob, which is normal.

Yea dont let the lill' shifter get to ya ;)

My car also has that problem? so what do i tell the dealer? do i say Yea its doing this fix it or something? their probably just going to say its normal and not check it out, my dealer is an ass

I had same problem, and they replaced the mount but problem still persists.

I took it in again, and they said that was normal (then I made them sit in it with me, and they confirmed that there was a vibration. It took me 15 seconds to get them notice it and they had the car for hours!!!)

Next time I took it in, they said the motor mount is fine and it was my gas!!!! What??!? They asked me if I was using lower octane gas and I told them I always used premium (93) and they said they experienced similar problem and fixed it by putting chevron 93 gas!
I don't think whole engine would shake because of bad gas! B**lSh*t!

If I can't get this problem fixed in next couple of months (I don't have time to spend all my time in the dealership), I am trading mine in, not because I hate the car but because of MAZDA's inability to service RX-8 properly. I will call this a failed experiment if I do say good bye.

Next time I took it in, they said the motor mount is fine and it was my gas!!!! What??!? They asked me if I was using lower octane gas and I told them I always used premium (93) and they said they experienced similar problem and fixed it by putting chevron 93 gas!
I don't think whole engine would shake because of bad gas! B**lSh*t!


I remember reading one of the posts that said lower octane gas caused vibration/rough idle. So there might be some truth to it.

My car vibrates too. And I use 91 all the time. So, I guess there is definitely more than one reason....

I will bring my car to the dealer and see what they have to say, but won't hold my breath on them fixing it.

Just an FYI, I inspected the motor mounts on my 8 (17k miles, 05/03 build date). There are three yellow dots on it.. but as far as I can tell no cracks.

I have pictures of the mount if anyone cares.

So speaking of the cracks where are they present? At the weld of the two support posts and the metal ring?

I know this is an old post but, the 3 yellow dots means that your Mazda dealer mechanic has inspected your mount on more than one occasion...they are doing their job correctly..
Whenever there is a mechanical inspection on an external mechanical part required by Mazda Japan a "good" dealer will always mark it with a yellow dot to visually prove the job is done.

As we know the engine mounts have been modified a few times by the factory, they wont be doing a recall as such, but repair at service schedule for owners who complain of excessive vibration.

As a suggestion to satisfy your mind and to know what mount is in your car and the Part Number, get friendly with your Mazda Parts Guy, they can look up exactly what part(s) are fitted to your 8 at production and give you the part number(s). Don't rely on the info from mechanics or even Service Managers, the parts guys know more on what parts are installed on your 8 before any TSB is issued.
Take your model chassis number into the Parts Department with you.
Remember to ask the parts guy for the part number that was installed on YOUR CAR at production, then ask has it been modified since.

You can then talk to your techs and if required get the new (modified) parts installed., or, at least you will know that you have the lastest parts already in your RX-8.

A modified Mazda part will always have a slight change to the part number at the end..ie -39-040, then -39-040A, then -39-040C, the "C" is the latest part.

Does anyone have a cracked motor mount they don't want? I would like to tear it apart and fill with some 90A durometer urethane that I have left over.

The vibration problem is a result of the car running to lean at idle. I know because I've run the car off of a standalone for fuel only and I can make the problem go away if I richen the afr up at idle. I think the injectors struggle to keep it lean at idle and their constant dance of cycling on and off is what causes the idle to be rough. The negative timing might also contribute, I'm not sure since I haven't messed with that yet.

Why it gets worse with the A/C on I'm not sure.

The vibration problem is a result of the car running to lean at idle. I know because I've run the car off of a standalone for fuel only and I can make the problem go away if I richen the afr up at idle. I think the injectors struggle to keep it lean at idle and their constant dance of cycling on and off is what causes the idle to be rough. The negative timing might also contribute, I'm not sure since I haven't messed with that yet.

Why it gets worse with the A/C on I'm not sure.
Quite obvious, if you get a richer mixture, it reduces cycle-by-cycle combustion variations. You'll get the same improvement if you increase idle speed, or load. The fact is, the engine must run at lambda = 1 in idle condition for emission purposes.

The best solution would be, in my opinion, to increase idle speed by 100 - 150 rpm.

Fabrice

I have about 18K miles on my Auto RX-8, everytime I stop at a light, the car shakes like no other and it is probably the most annoying thing thats happened to my RX-8, what should i tell the dealership so they can fix this, someone please help me, and if there is any way you can email me at Ryan.Q@godirectlending.com with the information, thanks a lot.

I'm fed up with it too. I'm now working on an auxiliary electronic device (yes, yet another "box") that will enable to raise the idle speed and therefore making it more stable. No need to reprogram the PCM (nobody can for the moment anyway), it wil connect to 3 wires from the engine loom, plus 12V and ground.
Will work on any ECU controlled gasoline engine.

Fabrice

I had the problem with my car vibrating way too much at idle. I have an automatic, not manual. I took it in for service today and they fixed it up with no problem. They replaced the motor mounts and the receipt said that the old ones were "distorted". I was glad they had the parts in stock so I didn't have to wait for them.

NOW that's how a GOOD dealer should operate...hassle free for the owner/customer..they have a good experience.

I am being presumptuous here, but, at a guess this dealer "services" their clients the way they should, they probably have an adequate spare parts store with switched on staff/good inventory, and a service department that gets the job done.

ie. parts in stock and the job is done with little fuss, and because the parts were there the customer did not have to come back..
which is a cost saving for the customer and the dealer., not to mention the great word of mouth advertising by the owner.

As an ex Mazda parts and fixed operations manager this experience is what all dealers should strive for....sorry for being a little self indulgent here...its the Mazda blood in me.

The parts system shows the mounts have been modified 3 times.

F151-39-040C (HP)
F151-39-050C (SP)

The latest mount should have a heat shield to protect the rubber from the exhaust heat.
Looking at the parts designations, this does not look like a revised mount, but just the second shoe dropping. (HP) would be the mount for the high power engine, (SP) for standard power.
Mitch (owner of a standard power (auto) that has the rattle at idle symptoms. My dealer found nothing when I brought it up before; now, thanks to you guys, I can make him take me seriously.
Mitch

checked my car today,

when i started my car. it does not have any vibration. but when i am driving, after i drive over 15 minutes and idle. the small vibration came out. when i stop on traffice lights.

is this normal for Type E, 4AT?

what is the octane level of Shell super (RED), and shell unleaded (green)?