oggie_

Hello to all RX-8 luvers out there! It is sooo nice to know that there is so big community around this car.

I fell in love with this car few years ago and I knew im goanna have it someday.
After few months of searching i found the perfect one. It is a 2007 231ps black beaty in a perfect condition and motor running flawless.

I paid the car and started my journey from dealership to home (approx. 180km)
Half way home strange things started happening. CEL started to blink and car lost power, than the blinking stopped and car was running normal again. This repeated few times and then came big surprise. I heard strange noise and smell of something burning.
Car lost power completely. I had to stop on the side of autobahn. When I looked under the hood I saw some water coming from a/c air intake. Then I looked under the car and saw some liquid. I touched it and smelled it, it was pure water. I started the car and I seemed to work fine. When I stepped on gas pedal I heard same strange noise. I got out of the car looked under it and pressed gas pedal with my hand. I could locate the sound source, it was a joint between CAT and rear exhaust leaking air gases on the sides.

I had to tow the car back to dealership. They told me that CAT filed, parts of it clogged the rear exhaust and the air could not escape causing the car to lose power. They told me they will replace the CAT for free and that I can have my car in few days.

My question is, what caused the CAT to fail? Could that be sign of much bigger motor problem coming soon? Should I ask for my money back and look for other rex???

Regards from Germany...

BigCajun

iTrader: (1)

Welcome.
Bad beginning for you.
Misfires kill the cat.
Flashing CEL means misfires.
Usually bad coils are the culprit. Coils plug wires (leads, cables) & plugs changes are recommended every 30k miles. Have you read the new owner stickies? Lots of info there.

It's a hard call, if it was partially blocked and the previous owner ignored the CEL, & continued to drive it, the engine could be damaged, shortening it's life or it could already be dead.
I would lean towards a refund, and try to find one that has a better, known history.
Be sure to get a rotary specific compression test on any 8 you consider.
No test, no deal.
Good luck!

BigCajun

iTrader: (1)

I bought my O4 GT 2 1/2 years ago with only 18k miles on it. 4 days later the CEL came on, checked it, PO420 cat below threshold.
I had a lot of experience with piston engines & thought it was running too good for a bad cat. I stupidly ignored it for quite a long time, then I started getting the flashing CEL & it would run rough at high RPM, then scanned it & got a misfire code, replaced the coils, plugs, & wires, still had the flashing CEL.
I finally dropped the cat & discovered the front half had broken up, clogging the back half.
Put a new midpipe on, problem solved.

Which leads me to believe that if the previous owner drove it long enough for the cat to completely break up, there's a higher chance the engine was damaged.

gwilliams6

Get your money back and look for a better RX with known history as BigCajun recommends. Don't let them talk you into keeping it. If the law is on your side to get a refund this early after purchase, then do that. Your engine could be dying and that could cost thousands.

ken-x8

Getting your money back is the best plan.

If you do decide to keep it, make it conditional on passing a rotary compression test. Also, insist that the new cat is a genuine Mazda part and that they replace the coils and plugs. A common cause of cat failure is ignition failure, which lets raw gas flow into the cat. The burning smell would have been the cat overheating from the gas burning.

Ken

oggie_

Thank you all for fast answer. I was holding my thumbs for positive info from you because i really fall in love with this car. It has only 80000km and it is literary like new (6/2007). Black color, chrome rims, beige leather, Bose, satnav, cruse, PERFECT condition. It drove perfect on test drive and first 100km.
I goggled a lot regarding misfire problem and found somewhere that CAT alone could be the source of misfiring, and that replacing CAT could solve the problem. The thing is I got for really good price and investing 1000eur more would still be acceptable for me, but new motor (around 4000-5000eur here) would be way too much to invest. I will definitely ask them to measure compression on rotors.

Is there any chance, in your opinion, that after replacing CAT everything stays ok for at least next 20k kilometers???
Finding good rex is almost impossible in Germany could be because there is no speed limits on autobahn

ken-x8

If compression is good, then with a new cat and ignition I'd expect it to last 20 km.

I'm basing that on one data point, my own experience with bad coils and cat. At 43000 miles, with no warning I got a flashing CEL and loss of power. Made it home, running badly. Drove to the dealer and barely made it. Misfiring, stalling unless I kept on the gas, sounded horrible. Barely made it. Coasted into the service bay with smoke wafting from under the car.

Both coils for the rear rotor had failed. Took out the cat and one of the O2 sensors. They replaced the cat, sensor, plugs, wires and coils. Ran fine, and is still running great at 65,000 miles. No deeper cause than the coils failing, which does happen with 8s.

It will come down to having faith in the dealer to fix it right. And wondering what else might have caused the last owner to get rid of it. The water thing sounds odd. Do you think it might have just been the usual condensate?

Ken

BigCajun

iTrader: (1)

The bad cat causes misfires due to the exhaust being restricted.
The cat went bad because of the bad ignition components.
If the cat is replaced without fixing the ignition, the same problems will occur.
You could replace the ignition parts & the cat & it could appear to run fine when in reality the engine could already be failing, and it's just a matter of time before you have to replace it.
There is a good chance it's already failed.
Get a rotary specific compression test no matter what.
Then you will know if you have to replace it, costing you many thousands of dollars.

If you don't do that then you're taking a HUGE gamble.
Only you can decide if it's worth it.
I don't think it's worth it unless it passes a compression test.
Then you have to maintain it religiously, or you can expect more trouble.

oggie_

Thank you a lot, your tips are of great value to me! I will take all this information in consideration when I go to dealership again, and then write how it all went.