Engine 'Rattling' Sounds when revving under load
05-17-2010, 05:31 PM
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Engine 'Rattling' Sounds when revving under load
So today I noticed the 'lack of power' symptoms in my car in all my gears - no power at all and having trouble even accelerating to 60 km/h.
Also I'm hearing rattling sounds from my engine compartment when revving past 3500-4000 rpm under (considerable) load in any of the gears. By 'considerable' load I mean I'm gassing quite hard but not flooring it.
From stand-still I can get to about 40 kmph or so in first gear and the rattling sound isn't so bad in 1st, but once i shift to second I notice that my acceleration is suffering A LOT and I'd have a hard time getting to 60+ kmph, I'd get there eventually, but very slowly.
So my question is, is this the typical 'loss of power' symptom that the other 8s have experienced? or is this something entirely different (the rattling sound in the engine area)??
I'm bringing my 8 to scarb mazda tomorrow to check it out, but I'm not sure what i should expect.
Also I'm hearing rattling sounds from my engine compartment when revving past 3500-4000 rpm under (considerable) load in any of the gears. By 'considerable' load I mean I'm gassing quite hard but not flooring it.
From stand-still I can get to about 40 kmph or so in first gear and the rattling sound isn't so bad in 1st, but once i shift to second I notice that my acceleration is suffering A LOT and I'd have a hard time getting to 60+ kmph, I'd get there eventually, but very slowly.
So my question is, is this the typical 'loss of power' symptom that the other 8s have experienced? or is this something entirely different (the rattling sound in the engine area)??
I'm bringing my 8 to scarb mazda tomorrow to check it out, but I'm not sure what i should expect.
05-17-2010, 05:32 PM
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are you sure the rattling is coming from your engine bay and not from your catalytic converter? My aftermarket cat rattled under heavy acceleration when it was broken.
05-17-2010, 06:11 PM
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I'm running on the OEM cat and exhaust but yeah I'm pretty sure it's from the engine compartment, and the sound is LOUD. When my brother took the car to check it out, I could hear the sound a good 100-200m away
05-17-2010, 07:15 PM
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05-17-2010, 08:26 PM
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I'm getting this as well recently... however only intermittently. Exact same symptoms as you Maffu.
My mechanic cut the heatshield off as it was rusted off pretty much, so it isn't that causing the noise.
If/when they diagnose what it is, I'd be very grateful if you post what it is... so I can pry myself away from work and pay Scarboro Mazda a visit, lol.
My mechanic cut the heatshield off as it was rusted off pretty much, so it isn't that causing the noise.
If/when they diagnose what it is, I'd be very grateful if you post what it is... so I can pry myself away from work and pay Scarboro Mazda a visit, lol.
05-17-2010, 09:11 PM
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CAT!
heat shield isn't going to reduce power anything like that, it is just annoying more than anything, my beater does that and I'm to lazy to fix it, it's a beater lol
heat shield isn't going to reduce power anything like that, it is just annoying more than anything, my beater does that and I'm to lazy to fix it, it's a beater lol
05-17-2010, 09:15 PM
#11
I concur and think it's the CAT..
My car recently does this randomly too... There are pieces bouncing around in the CAT, sometimes it blocks it, sometimes it doesn't...
The CATs are notoriously weak on our cars. Glad it's covered up to 128,000km or 8 years.
My car recently does this randomly too... There are pieces bouncing around in the CAT, sometimes it blocks it, sometimes it doesn't...
The CATs are notoriously weak on our cars. Glad it's covered up to 128,000km or 8 years.
05-17-2010, 10:43 PM
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okay well thanks everyone for your input =D I'll tell scarb mazda to check the cat along with all the symptoms that I just experienced and I'll post up what they say later.
05-18-2010, 07:13 AM
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Rotaries put out some crazy exhaust. Even with the newly designed ports on the Renesis, it still creates some crazy amount of carbon.
Which is why all RX-7's (at least 3rd gens) run cat-less. On our cars there were 3 cats. 2 of which were located right beside the turbos and then the main cat near the middle of the car.
Car got ridiculously hot due to those damn cats. They were notorious for frying our turbos as well since they sat right next to them.
I think the 2nd or 3rd thing I did to my car was remove the cats. All of them! Run straight pipe into a silencer and then out the catback. You can't imagine how much smoke comes out of these rotaries!
And since she's turbo, the added flow was very noticable.
I would definitely run the RX-8 catless. Although I think 2 (or is it 1) of your sensors have to detect the stupid cats?? I can't remember. I just remember the ECU is very finicky when it comes to fooling around with the RX-8.
Which is why all RX-7's (at least 3rd gens) run cat-less. On our cars there were 3 cats. 2 of which were located right beside the turbos and then the main cat near the middle of the car.
Car got ridiculously hot due to those damn cats. They were notorious for frying our turbos as well since they sat right next to them.
I think the 2nd or 3rd thing I did to my car was remove the cats. All of them! Run straight pipe into a silencer and then out the catback. You can't imagine how much smoke comes out of these rotaries!
And since she's turbo, the added flow was very noticable.
I would definitely run the RX-8 catless. Although I think 2 (or is it 1) of your sensors have to detect the stupid cats?? I can't remember. I just remember the ECU is very finicky when it comes to fooling around with the RX-8.
Is this true? Does it also cover the heatshield? (Mine went south some time ago and the dealer said the only way to replace it was with an whole new cat)
05-18-2010, 05:17 PM
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I had some similar problems too. I took my car to the dealership and I got a new cat, but then the rattling still persisted so I took it again and they said i had a broken engine bracket mount. They fixed that and the car was fine! =D
05-18-2010, 06:13 PM
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Spend $100 and get the compression tested and request the print out. Trust me on this.
Both my replaced motors started out with the exact same symptom...at the same RPM load.
Railton
Both my replaced motors started out with the exact same symptom...at the same RPM load.
Railton
05-18-2010, 06:13 PM
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So I took her to Scarb Mazda today, and told them about the rattling sounds and the loss of power, also told them to check the cat.
Turns out that nothing was wrong with the cat, loss of power was due to dying ignition coils, ignition wires and spark plugs, all of which need to be replaced. I'll be doing that later this week =) but since yesterday night, I haven't heard the rattling sound again even though we didn't do anything to the car. I'm guessing it might be random misfiring causing the loud noise which would also explain the huge drop in fuel economy.
Once again thanks for all your suggestions and inputs!! Hopefully I can get her running at full power again before the upcoming track days =)
Turns out that nothing was wrong with the cat, loss of power was due to dying ignition coils, ignition wires and spark plugs, all of which need to be replaced. I'll be doing that later this week =) but since yesterday night, I haven't heard the rattling sound again even though we didn't do anything to the car. I'm guessing it might be random misfiring causing the loud noise which would also explain the huge drop in fuel economy.
Once again thanks for all your suggestions and inputs!! Hopefully I can get her running at full power again before the upcoming track days =)
05-18-2010, 09:06 PM
#22
I don't know. From my recent coil life research, there is no definite answer. The original revision coils in 2004 models died faster. Then there was a revised version... last two letters "9U" in the part number. Still it's inconclusive from my research. Some replaced it every 20,000 miles, some ran theirs to 100,000 miles and were fine.
If you are buying coils now, tell me where you're buying, because I want to buy them with you, perhaps we can save on shipping. I plan on installing them myself. I've never done it before, but it looks easy enough, I can give you a hand if you need help. I am confident I can do it.
If you are buying coils now, tell me where you're buying, because I want to buy them with you, perhaps we can save on shipping. I plan on installing them myself. I've never done it before, but it looks easy enough, I can give you a hand if you need help. I am confident I can do it.
05-18-2010, 09:17 PM
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Interesting.... my 8 has started to rattle as well.. but it's closer to red line (around 7k rpm). I'm pushing 98,000km though.
I'm planning to do all fluid flush and refill before I worry about it and take it to the dealer... (just bought this car used).
I'm planning to do all fluid flush and refill before I worry about it and take it to the dealer... (just bought this car used).
05-18-2010, 10:42 PM
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I don't know. From my recent coil life research, there is no definite answer. The original revision coils in 2004 models died faster. Then there was a revised version... last two letters "9U" in the part number. Still it's inconclusive from my research. Some replaced it every 20,000 miles, some ran theirs to 100,000 miles and were fine.
If you are buying coils now, tell me where you're buying, because I want to buy them with you, perhaps we can save on shipping. I plan on installing them myself. I've never done it before, but it looks easy enough, I can give you a hand if you need help. I am confident I can do it.
If you are buying coils now, tell me where you're buying, because I want to buy them with you, perhaps we can save on shipping. I plan on installing them myself. I've never done it before, but it looks easy enough, I can give you a hand if you need help. I am confident I can do it.
or do you have any idea where we can get a group buy for cheap?