Help!
09-15-2012, 07:40 AM
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Help!
We purchased our 2006 (190) RX8 7 days ago. We checked it and it was fine. Been driving perfectly with no problems starting hot or cold. Coming home from work yesterday it started to misfire with the engine check light flashing. Limped home by which time it was running very rough, smoke was pooring from the bonnet and filled the inside of the car.All levels where checked and all ok, no changed in oil level , no raise on the engine temp gauge all gauges read OK!
The smell was awfull and it was very hot.
My personal feeling is that the CAT has gone ,please help with sugestions.
The garage are collecting it today and are going to look at it, but any ideas would be greatly appreciated
Thanks guys
The smell was awfull and it was very hot.
My personal feeling is that the CAT has gone ,please help with sugestions.
The garage are collecting it today and are going to look at it, but any ideas would be greatly appreciated
Thanks guys
09-15-2012, 07:57 AM
#2
Inspect the cat, do a compression test and then replace the whole ignition system in this order.
Chances are the car was a lemon and you are going to spend some money on it in order for it to work.
Check the source of the smoke as well.
Chances are the car was a lemon and you are going to spend some money on it in order for it to work.
Check the source of the smoke as well.
09-15-2012, 08:21 AM
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You are probably at the point of cascading failures from ignition neglect. Read these two sections below, and then move into the thread to fix misfiring.
https://www.rx8club.com/rx-8-discuss...t-here-202454/
https://www.rx8club.com/rx-8-discuss...t-here-202454/
Specific Issues:
- Misfires are shown by a blinking check engine light (CEL), and are usually caused by a failing coil, failing plug wire, and/or failing spark plug. They can also be caused by cat failure, engine failure, vacuum leaks, fouled e-shaft sensor, dirty MAF, missing intake screens, aftermarket intake, failing intake valve actuators and a few other items. Start here for diagnosis: https://www.rx8club.com/tech-garage-...t-here-222280/
- Misfires are shown by a blinking check engine light (CEL), and are usually caused by a failing coil, failing plug wire, and/or failing spark plug. They can also be caused by cat failure, engine failure, vacuum leaks, fouled e-shaft sensor, dirty MAF, missing intake screens, aftermarket intake, failing intake valve actuators and a few other items. Start here for diagnosis: https://www.rx8club.com/tech-garage-...t-here-222280/
Importance of Ignition Health:
************************ READ THIS!!!! ************************
One of the most often overlooked or ignored parts of RX-8 ownership is the health of the ignition system. This includes the ignition coils, spark plug wires, and spark plugs. They fail. Often. So often as to be critical parts of regular maintenance.
Before I detail why, check out the first post of this thread here: The impact of old coils, wires, & plugs - RX8Club.com (owner's post here: [FEELER] Spring 2012 MM Tuning / Dyno Day @ Speed1 Allentown (formerly KDRotary) - Page 8 - RX8Club.com)
The owner's power dropped from 199whp to 172whp JUST from failing ignition. That's a 13.5% power loss!
Do I have your attention now? Good.
Mazda officially lists the plug wires and plugs as part of regular maintenance, but not the coils. Many dealers STILL don't know how easily the coils can fail. And they fail about the same time as the wires and plugs, which is about every 30,000 miles. Some can last longer, some shorter, and it's more related to your total RPMs than it is to your mileage. Highway cruising is easier on the coils than spending a day pounding around a race track.
When coils fail, they don't suddenly shut off. They start producing weaker pulses scattered among strong ones. The rate of weak pulses slowly increases and pulses start getting dropped entirely, which is where misfires start. All of this means that you aren't burning all the fuel and aren't using all the air that the engine pulled in for that combustion, and it unburnt fuel and air gets dumped into the exhaust, where it happily ignites with the presence of plenty of heat. This saturates the cat in both fuel and heat, and will rapidly kill the cat (A $1,300 USD replacement). Continuing to drive on a failing cat will add other problems such as engine damage and vehicle fires. I am not exaggerating, this can happen with just a single cat failure!
Plug fouling and wire failure is largely the same result, since all 3 pieces are needed for a complete spark. Foul the plug and it doesn't matter if the coil and wire are good. Break down the wire and it doesn't matter if the coil and plug are good.
Symptoms of ignition failure include: Power Loss, mileage drop, unstable idle, bad idle, inability to idle, shaking at idle, unstable high rpm, misfiring, flashing CEL, coughing engine, glowing cat, flooding, inability to start, inability to pass an emissions sniffer test, and just about anything you can think of where a weak or missing spark causes problems.
And if one fails, it will cascade to the other trio on the same rotor. A plug that can't fire will start fouling the other. A coil that can't fire a plug starts wearing out rapidly (if you want to test this, just unplug a wire from a plug and run the engine for a while. The coil will rapidly fail. Not unique to rotary engines)
Why do coils fail so easily?
This is largely because Mazda opted for cheap coils because of RX-7 owner complaints about how expensive their coils were. The RX-7 coils lasted much longer though. So Mazda went cheap, and so we have to replace regularly. And you can't compare to piston engine coils. A piston engine with the same setup of 1 coil for 1 plug has an average RPM of about 2,500rpm and the coil is firing every other revolution, so the coil is firing about 1,250 pulses per minute. Our rotary has an average RPM of more like 4,000rpm, and each coil fires every revolution, so about 4,000 pulses per minute. That's a bit over 3 times more. Even a piston max RPM of about 6,000rpm vs our 9,000rpm makes the difference 3,000 pulses per minute vs 9,000 pulses per minute, or 3 times as fast.
If our coils would last about 3 times longer, you are talking an average of 90,000 miles.
So keep your ignition healthy!
************************ READ THIS!!!! ************************
One of the most often overlooked or ignored parts of RX-8 ownership is the health of the ignition system. This includes the ignition coils, spark plug wires, and spark plugs. They fail. Often. So often as to be critical parts of regular maintenance.
Before I detail why, check out the first post of this thread here: The impact of old coils, wires, & plugs - RX8Club.com (owner's post here: [FEELER] Spring 2012 MM Tuning / Dyno Day @ Speed1 Allentown (formerly KDRotary) - Page 8 - RX8Club.com)
The owner's power dropped from 199whp to 172whp JUST from failing ignition. That's a 13.5% power loss!
Do I have your attention now? Good.
Mazda officially lists the plug wires and plugs as part of regular maintenance, but not the coils. Many dealers STILL don't know how easily the coils can fail. And they fail about the same time as the wires and plugs, which is about every 30,000 miles. Some can last longer, some shorter, and it's more related to your total RPMs than it is to your mileage. Highway cruising is easier on the coils than spending a day pounding around a race track.
When coils fail, they don't suddenly shut off. They start producing weaker pulses scattered among strong ones. The rate of weak pulses slowly increases and pulses start getting dropped entirely, which is where misfires start. All of this means that you aren't burning all the fuel and aren't using all the air that the engine pulled in for that combustion, and it unburnt fuel and air gets dumped into the exhaust, where it happily ignites with the presence of plenty of heat. This saturates the cat in both fuel and heat, and will rapidly kill the cat (A $1,300 USD replacement). Continuing to drive on a failing cat will add other problems such as engine damage and vehicle fires. I am not exaggerating, this can happen with just a single cat failure!
Plug fouling and wire failure is largely the same result, since all 3 pieces are needed for a complete spark. Foul the plug and it doesn't matter if the coil and wire are good. Break down the wire and it doesn't matter if the coil and plug are good.
Symptoms of ignition failure include: Power Loss, mileage drop, unstable idle, bad idle, inability to idle, shaking at idle, unstable high rpm, misfiring, flashing CEL, coughing engine, glowing cat, flooding, inability to start, inability to pass an emissions sniffer test, and just about anything you can think of where a weak or missing spark causes problems.
And if one fails, it will cascade to the other trio on the same rotor. A plug that can't fire will start fouling the other. A coil that can't fire a plug starts wearing out rapidly (if you want to test this, just unplug a wire from a plug and run the engine for a while. The coil will rapidly fail. Not unique to rotary engines)
Why do coils fail so easily?
This is largely because Mazda opted for cheap coils because of RX-7 owner complaints about how expensive their coils were. The RX-7 coils lasted much longer though. So Mazda went cheap, and so we have to replace regularly. And you can't compare to piston engine coils. A piston engine with the same setup of 1 coil for 1 plug has an average RPM of about 2,500rpm and the coil is firing every other revolution, so the coil is firing about 1,250 pulses per minute. Our rotary has an average RPM of more like 4,000rpm, and each coil fires every revolution, so about 4,000 pulses per minute. That's a bit over 3 times more. Even a piston max RPM of about 6,000rpm vs our 9,000rpm makes the difference 3,000 pulses per minute vs 9,000 pulses per minute, or 3 times as fast.
If our coils would last about 3 times longer, you are talking an average of 90,000 miles.
So keep your ignition healthy!
09-15-2012, 08:26 AM
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Thank you, I had read these previously, everything was cahnged in April, and had a full service with new ignition last November! We are gutted! Love the car , had an rx7 many moons ago and loved that to! Never had any issues with the 7 apart from mega expensive exhaust replacement!
09-15-2012, 08:31 AM
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Your cat may have been on the way out at that point then, and it finally failed.
I'd also say that you should let the garage know that you can have a cat failure and it not show up on the computer. So if nothing is on the computer saying that the cat failed, have him remove the cat and look inside. Should be a healthy screen visible. If he/you can see the tip of the O2 sensor inside before the screen, then it means the first one is gone, and probably packed into the 2nd one, clogging the pipe.
I'd also say that you should let the garage know that you can have a cat failure and it not show up on the computer. So if nothing is on the computer saying that the cat failed, have him remove the cat and look inside. Should be a healthy screen visible. If he/you can see the tip of the O2 sensor inside before the screen, then it means the first one is gone, and probably packed into the 2nd one, clogging the pipe.
