Problems at Startup
 

I have a 2004 RX-8 which I bought new in the summer of 2003. The car gets VERY little use and has less than 2,000 miles. I do generally start up the car, take it out of the garage, and leave it running for a bit. If I don't start up the car for maybe 2 weeks, the car has major problems starting. The engine sputters loudly, the exhaust smells like burned oil, and the car vibrates. The engine also feels like it is about to stall and misfires. The CEL comes on and starts blinking. This all goes away though after about 10 minutes of running. I have taken the car to the dealer, and they have replaced plugs, reflashed the PCM, and supposedly performed the 4206F recall. I was told that nothing was wrong with the car. The car generally drives properly, but these start problems I feel are going to ruin the car. Has anyone had a similar experience with their RX-8?

Sitting is extrememly hard on a car. Maybe you should try driving it?

sell it to someone who will drive it. not meaning to be harsh but i have what is considered to be very light miles for an rx-8 bought in 2003(just over 29k now) 2k miles is abuse to the car. there is oil and fuel just sitting in the engine wetting the plugs between startups- when it finally fires its just as if it had been flooded(which is not far from reality) so you see all the smoke etc. but that is also ruining your cat. 2 weeks or more between starts is just way too long

You need to get that car out and beat the crap out of it a couple of times.
Then, sell it because it will fetch top dollar.

Allowing a rotary to sit is almost worse than driving it out of oil.

This car doesn't get driven often since I use mass transit for work and we have other cars in the family. The car was bougt to be an occasional fun car, not a daily driver. This was to be like my 'exotic car' and, like most exotics, people never put on much mileage. I have never had this issue with any other car that I have ever owned. I am just trying to find out is causing this and remedy it. Usually I would start the car, let it run for about 20mins, and then put it back in the garage. Actually, even if I go 2 days between starts, the car sounds like it is backfiring and vibrates terribly. It then goes away after about 10 mins of running.

we just gave you the cause and the remedy

Okay, thanks for the info. I never had this issue with any other car we owned (Miata, Cadillac, Acura). So basically, if the RX-8 isn't used a daily driver, these problems will happen. I just wish I knew this when I bought the car....

That is the issue with ANY rotary. You should do your research before you drop a dime on an "exotic". No less so when it is only 320k dimes.

BTW - keeping a Ferrari in the garage will yield the same result.

It's funny you mention Ferrari because I happened to be friends with the VP of Ferrari NA. (Maybe one day if I hit the lottery, I will buy...) Anyway, they usually RECOMMEND to do exactly what I am doing with my RX-8.

I was one of the initial buyers of the RX-8 at the time when the car was selling above MSRP. I actually asked the salesman (since I knew someone who had an RX-7 with numerous engine problems) if the Renesis would have problems if left to sit for a week or so. He assured me that it would be no problem, and that the RX-8 they had on display never exhibited any such issue. I actually never even got to test drive the car as the dealerships at the time didn't have a demonstration unit.

I am very curious though about what is actually happening. So if I understand, oil is sitting in the combustion chamber when the car is shut off and the spark plugs are sitting in the oil. As the car sits, the oil soaks the spark plugs causing a misfire. Is that the problem or is more oil entering the combustion chamber as time goes on?

rotaries hate to sit. Just a fact of rotary ownership. It's going to happen everytime- there is no fix except to drive it more.

BTW; sounds like you're also going to be prone to carbon lock because I doubt you flog your 8 very much if at all. You need to redline and beat her everyone now and then.

I let mine sit all the time.

Your problem is letting it idle for 20 minutes. Worst thing you can do.

You need to take it out and run it hard, otherwise it's not a fun car to have.

Mine sits for two weeks or more between drives.

Another thing that kill it is the clock. It drains the battery and makes it hard to start. You have to drive this car hard when you take it out.

Two weeks? Sad.
I think the OP probably lets it sit for months.
Its 4 years old and he has less than 2k miles on it.
Mine is exactly the same age and its approaching 55k miles and I don't think I drive mine hardly at all.
I have no commute and I walk/bike a lot.

I'm surprised they'd recommend that for any car. I wonder if Ferrari tunes their cars to put up with that, since I suspect a good number of Ferrari owners treat their cars like works of art rather than driving machines.

Did I understand correctly that you just let it idle for 20 minutes? You really should at least drive it for those 20 minutes.

I've had a couple of cars that got demoted to occasional beater status. If not run for a couple of weeks, they tended to run rough when first started. Sitting just isn't great for a car.

You could have problems from stale gas. 2000 miles in four years. That's a fresh tank every 4 to 6 months. Why don't you use the 8 on your next weekend excursion, put on enough miles to burn off the old gas, then add some stabilizer when you fill up.

Ken

This is a rotary engine and its requirement are different. When it idles for those few minutes it is running Rich and carbon is building up one layer on another because it never gets burnt off. How many times have you changed the oil? The service manual says change the oil every 4-6 months depending on the type of use your car gets. Don't wait for miles, there's most likely a lot of water in the all the lubrications in your car.

Thanks for the input. I would say the most the car has ever been left to sit without starting would be about 2 weeks. The car does get 'driven' when we do take it out. That was the point of it, to enjoy the sports car feel. One thing that sold me on the RX-8 versus any piston engine car was the ability to so linearly rev to 7000-8000rpms. So when we do take it out, I do rev it high especially since I bought the MazdaSpeed CAI and exhaust.

Razz1, you said that you do let your car sit for about 2 weeks between drives. Have you ever had the issues I have been having after letting it sit for a while? I have noticed that it was necessary to charge the battery from time to time as the clock/alarm does kill it.

I was thinking that maybe the ignition coils might be bad also and contributing to this. Here's the interesting part: If I leave the car sitting, start it, and then about 30 seconds later put it into gear and start driving, the car feels as though it will stall right out (no power). If I leave it running for a few mins though then start driving, it reacts much better.