F.W.I.W.

Background: Early 2004 MT GT, 30K miles, all recalls/updates done, regular maintenance done, never flooded, no problems to date.

I was riding on the Interstate (65-70 mph) when all of a sudden I got a blinking Check Engine Light and a loss of power. I pulled off and checked the book, which says that for a CEL "If the check engine light remains on or flashes continuously, do not drive at high speeds and consult an Authorized Mazda Dealer as soon as possible." So I drove my RX-8 slowly (45 mph or less) and left it at the dealer's overnight drop. FYI, I noted a lot of heat from under the car when I dropped it off and asked them to check the Cat.

The next day I get a call saying that two coils had failed and I needed them replaced along with all four plugs ($499.93) but that the Cat was OK. I told them to go ahead and do the repair. When I picked up the car I immediately took it out for a test drive and found it ran fine except for hard acceleration over 6K rpm. Acceleration up to 9K has always been baby smooth and now it was stumbling when running above 6K. I took it straight back to the dealer.

Two days later I get a call that the Cat needed to be replaced but that Mazda USA would cover the cost. When I got the car back it was a little rough over 6K and that eventually smoothed out. Now, the only residual from the episode is a light rattle in the exhaust from pieces of the Cat liner that got blown into the muffler.

Warning: If this ever happens to you I recommend that get all 4 coils replaced (I didn't and regret it). The incremental cost is small and if 2 fail, the other 2 may not be far behind. Also, apparently another side effect from coil failure is to get small dings in the driver side door so be forewarned if your coils should fail.

Bottom line ... I understand about RX-8 coils and accept that they routinely fail. However, coil failure having a downstream side effect of burning-up the Cat really frosts me. There is no way to protect yourself short of replacing all four coils every 10K miles (a bit extreme). You would think the PCM would protect then engine/exhaust by cutting fuel to the rotor with coil failure.

 

first off, you got ripped by your dealership.

2 coils and 4 plugs + labor cost 499 bux? wow.

Let me guess, you dont push your car hard often do u?

Cuz if u did, Im sure u would notice the "coil's early dying symptoms"

Anyway, no the ECU will not know that the coils are going to "die", when it finally sense that its dead (not firing), then its usually too late.

for your "why coils will effect cat", thats because a under-performing/dead coil will have a weak/no spark. the result is a lot of unburnt fuel will go to your CAT, so yeah it kills your CAT like that.

From your words, your SSV is not working well, you might want to tell them to check it.

 

I don't disagree. Unfortunately I don't have time to do the work myself.


Wrong! I do push the car regularly and there were no symptoms prior to the failure on the interstate. If there had been symptoms I would have taken it to the dealer sooner.


Please read more carefully next time before you respond. I didn't ask why "coils effect cat" (I understand about the effects of unburnt fuel on the Cat). I said (basically IMHO) that it frosts me that coils can destroy the Cat and that the engine/exhaust wasn't designed to better protect itself.

 

How much is your time worth? coils and plus take about 2-3 hours with beer breaks.

And being "frosted" about the 500 dollar bill is nothing compared to the $1200 that they could have charged you for the cat if they decided not to cover it. (that's just for the cat, not installation, which takes about an hour)

You can always upgrade to BHR coils if you don't feel like changing out your coils ever again.

 

You must take a lot of beer breaks for a 2-3 hour coil/plug job

 

500 bucks is nothing, try getting a BMW repaired or Toyota.

 

You've seen me work...

 

I confess I didn't sweat the coil/plug cost because I was mostly concerned about maybe having to pay to replace the Cat.

The cost breakdown was:
$249 - parts
$218 - labor
$32 - tax and shop fees

Yes, the parts cost are inflated by 25%-30% over an Internet purchase of "genuine" Mazda parts. However, the labor includes diagnostic time as well as repair time so it wasn't that unreasonable, particularly since I wasn't in a position to do it myself and haven't found a small repair shop in Richmond that speaks RX-8.

 

I had to call today about a new Cat. It is running $1,600 from the dealer & $150 in labor for an install.