Types of motor failures and related symptoms
05-05-2010, 09:04 AM
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Types of motor failures and related symptoms
Hey everyone,
Can anyone give a quick list of the types of common RX-8 motor failures and the associated symptoms? My experience with a blown rotary ('93 RX-7) involved bad water seals due to overheating...the car became hard to start, was burning coolant (white smoke), etc. This is pretty clearly NOT what is happening with my car right now, so I'm curious if my symptoms match other types of relatively common motor failures.
FWIW, my current primary symptom is at low rpm under load the car has NO power. If I give it much gas it completely bogs down and goes nowhere, I have to very slowly let the revs build, or else rev it up while not under load, put it in gear and go. Over about 3K rpms the car feels more or less normal. I'm not seeing smoke or anything like that. I've been told by the dealer that they suspect a bad motor but I haven't yet done a compression test.
jds
Can anyone give a quick list of the types of common RX-8 motor failures and the associated symptoms? My experience with a blown rotary ('93 RX-7) involved bad water seals due to overheating...the car became hard to start, was burning coolant (white smoke), etc. This is pretty clearly NOT what is happening with my car right now, so I'm curious if my symptoms match other types of relatively common motor failures.
FWIW, my current primary symptom is at low rpm under load the car has NO power. If I give it much gas it completely bogs down and goes nowhere, I have to very slowly let the revs build, or else rev it up while not under load, put it in gear and go. Over about 3K rpms the car feels more or less normal. I'm not seeing smoke or anything like that. I've been told by the dealer that they suspect a bad motor but I haven't yet done a compression test.
jds
05-05-2010, 09:26 AM
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New Engine Club Thread - is a must read. Thought it couldn't, wouldn't happen to me and got a new engine and got my car back yesterday. 2004 RX8 65k well maintained miles
05-05-2010, 09:30 AM
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Yeah, that's what the dealer said as well. In fact, they ran tests that showed a small handful of misfires but not what they would expect from ignition problems, and the cat tested out fine.
The engine has 45K on it, nothing major in terms of mods, just Racing Beat CAI and cat-back exhaust.
As I moaned about in my other thread, because I've been doing my own service (i.e. oil changes) the dealer pretty much told me they're going to bend me over unless I have all my receipts, which of course I will never be able to find.
So my symptoms seem consistent with low compression? Dammit...I was hoping the dealer was lying or incompetent about that... :-(
The engine has 45K on it, nothing major in terms of mods, just Racing Beat CAI and cat-back exhaust.
As I moaned about in my other thread, because I've been doing my own service (i.e. oil changes) the dealer pretty much told me they're going to bend me over unless I have all my receipts, which of course I will never be able to find.
So my symptoms seem consistent with low compression? Dammit...I was hoping the dealer was lying or incompetent about that... :-(
05-05-2010, 09:56 AM
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Thanks, this sounds like good advice to me. I have Mazda North America's address handy as well, should I need to start firing off letters. I guess I should schedule that compression check, first off, just to be sure.
Bureau, try this;
Tell your dealer that you have meticulously self-maintained your vehicle, as that is your right under the Magnuson-Moss Act, and did not think you would have to take a defensive and paranoid posture with regard to Mazda's warranty compliance since they are a reputable company doing business in America. Then tell them that you will have NO PROBLEM finding hundreds and hundreds of other owners of 2004 and 2005 models who have had low compression issues when reaching 50K miles or above and that your engine falls into that category.
You have low compression, no signs of abuse of the car/engine, and it is well known that the RX-8 has several predictable problems, yours being one of them.
Tell your dealer that you have meticulously self-maintained your vehicle, as that is your right under the Magnuson-Moss Act, and did not think you would have to take a defensive and paranoid posture with regard to Mazda's warranty compliance since they are a reputable company doing business in America. Then tell them that you will have NO PROBLEM finding hundreds and hundreds of other owners of 2004 and 2005 models who have had low compression issues when reaching 50K miles or above and that your engine falls into that category.
You have low compression, no signs of abuse of the car/engine, and it is well known that the RX-8 has several predictable problems, yours being one of them.
05-30-2010, 12:06 AM
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Hey Ray,
What about this. When I start my car everything runs fine. After I'm driving for a while. My car seems a little bogged down if I hit the gas and the exhaust makes a deep toned noise. If I slow to a stop and try to take of fast its a little slower than usual. Do you happen to know what this could be? I have an 04 with 65k miles
What about this. When I start my car everything runs fine. After I'm driving for a while. My car seems a little bogged down if I hit the gas and the exhaust makes a deep toned noise. If I slow to a stop and try to take of fast its a little slower than usual. Do you happen to know what this could be? I have an 04 with 65k miles
06-01-2010, 12:39 PM
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Wondering if anyone can shine some light on this...
2004 MT with about 63k miles
Noticed about a week ago that my car was starting to shake while driving, especially at around 65mph or higher. Thought it may just be that I need my tires balanced, but the other day while idling at a stop light, the rpm's dropped below 1000 and the car started shaking almost like it was going to stall. I'm not sure if these 2 things are related or not? Also now the car seems to be shaking even when going slower than before. So much as I can't even see out of my rear view because its shaking so bad. The higher the rpm's the more the shaking it seems. The car also seems louder than normal. My gf asked if my car was going to take off like a plane because that's what it sounded like.
Also, had my cat, coils, plugs, and wires all replaced by Mazda last year.
2004 MT with about 63k miles
Noticed about a week ago that my car was starting to shake while driving, especially at around 65mph or higher. Thought it may just be that I need my tires balanced, but the other day while idling at a stop light, the rpm's dropped below 1000 and the car started shaking almost like it was going to stall. I'm not sure if these 2 things are related or not? Also now the car seems to be shaking even when going slower than before. So much as I can't even see out of my rear view because its shaking so bad. The higher the rpm's the more the shaking it seems. The car also seems louder than normal. My gf asked if my car was going to take off like a plane because that's what it sounded like.
Also, had my cat, coils, plugs, and wires all replaced by Mazda last year.
06-03-2010, 05:33 PM
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the e-shaft is the center shaft that the rotors rotate around, spinning it, which provides power to the transmission. The e-shaft sensor determines what the orientation of that shaft is, and thus, the position of the rotors. This then drives the ECU to know when to open which ports, which to provide a spark, etc...
Over time, this sensor profile can become slightly uncalibrated, and the resulting change in (effective) timing, ports not opening and closing the right positions, etc..., can cause power loss and other symptoms.
To reset the e-shaft profile, get in the car, insert the key into the ignition, turn to ON but not START. Immediately pump the brakes quickly. Keep pumping them until you see the oil pressure gauge sweep to the right and then back. It usually takes around 20 times. You only need to trip the brake light sensor I believe, no need to mash it to the floor. Once the gauge makes it sweep, turn the key to OFF, wait a few seconds, and you are good to go. This also resets the fuel trims and a few other learned tables, so your idle will be unstable and nearly stalling for at least 1 drive cycle. This method is referred to as the "20-brake-pedal-stomp" around here, although I've noticed that it is sometimes more and sometimes less than 20 stomps, though how much of that is just not recognizing the stomps, I don't know.
Over time, this sensor profile can become slightly uncalibrated, and the resulting change in (effective) timing, ports not opening and closing the right positions, etc..., can cause power loss and other symptoms.
To reset the e-shaft profile, get in the car, insert the key into the ignition, turn to ON but not START. Immediately pump the brakes quickly. Keep pumping them until you see the oil pressure gauge sweep to the right and then back. It usually takes around 20 times. You only need to trip the brake light sensor I believe, no need to mash it to the floor. Once the gauge makes it sweep, turn the key to OFF, wait a few seconds, and you are good to go. This also resets the fuel trims and a few other learned tables, so your idle will be unstable and nearly stalling for at least 1 drive cycle. This method is referred to as the "20-brake-pedal-stomp" around here, although I've noticed that it is sometimes more and sometimes less than 20 stomps, though how much of that is just not recognizing the stomps, I don't know.
06-04-2010, 08:34 PM
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FWIW, my current primary symptom is at low rpm under load the car has NO power. If I give it much gas it completely bogs down and goes nowhere, I have to very slowly let the revs build, or else rev it up while not under load, put it in gear and go. Over about 3K rpms the car feels more or less normal. I'm not seeing smoke or anything like that. I've been told by the dealer that they suspect a bad motor but I haven't yet done a compression test.
This is exactly what my car was doing as well. Compression test didnt indicate low compression and a spark plug/wire change basically completely rememdied the situation. I think it was basically two of the wires were loose fitting on one rotor causing misfires. Went from basically 11-12 sec 0-60s to solid 8-9 sec times even make scratches off the line! I have also been told poor compression would be reflected in all rpms not just down low.
06-07-2010, 08:38 AM
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My hard start/low power problems turned out to be coils/wires...BHR kit fixed it. The stalling out problem appears to be something different that gets triggered or fixed by messing with stuff...that makes it sound electrical but I'm not sure what. For now I'm not having that problem so out of sight out of mind :D
06-07-2010, 11:10 AM
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Wondering if anyone can shine some light on this...
2004 MT with about 63k miles
Noticed about a week ago that my car was starting to shake while driving, especially at around 65mph or higher. Thought it may just be that I need my tires balanced, but the other day while idling at a stop light, the rpm's dropped below 1000 and the car started shaking almost like it was going to stall. I'm not sure if these 2 things are related or not? Also now the car seems to be shaking even when going slower than before. So much as I can't even see out of my rear view because its shaking so bad. The higher the rpm's the more the shaking it seems. The car also seems louder than normal. My gf asked if my car was going to take off like a plane because that's what it sounded like.
Also, had my cat, coils, plugs, and wires all replaced by Mazda last year.
2004 MT with about 63k miles
Noticed about a week ago that my car was starting to shake while driving, especially at around 65mph or higher. Thought it may just be that I need my tires balanced, but the other day while idling at a stop light, the rpm's dropped below 1000 and the car started shaking almost like it was going to stall. I'm not sure if these 2 things are related or not? Also now the car seems to be shaking even when going slower than before. So much as I can't even see out of my rear view because its shaking so bad. The higher the rpm's the more the shaking it seems. The car also seems louder than normal. My gf asked if my car was going to take off like a plane because that's what it sounded like.
Also, had my cat, coils, plugs, and wires all replaced by Mazda last year.
You might want to rule out the engine mounts, after you are done checking the things Charles mentioned. Just give it a quick look, see if any of the two mount brackets are cracked, or if the rubber mounts are deformed. Some of the older models, '04&'05, had that problem and the symptoms are usually excessive shacking.
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