Won't rev past 6500
 

The last 2 weeks when I start the car in the morning ( about 4:30 am, 50 degrees outside ) the car immediately revs up to about 3500 and sits there for about 10 seconds before coming down to 2000 or so. It has never done that before?

The last 2 mornings when I go to leave and pull out on to the street the car won't rev past 6500 rpms in 1st gear and feels as though it is hitting the rev limiter? After shifting to 2nd, it'll rev up just fine all the way up to 9k. It just happened again this afternoon when I left for lunch ( the car's been sitting since 5 this morning and it was 1 pm when I left ). Any ideas? Thanks.

Car is cold..let it warm up and it will be fine. the ECU controls the max RPM/load until the coolant temp is warm

I've been having a similar problem - kinda of putters out at exactly 5500 rpm and only the first time (sometimes the second) time accelerating. After that it's fine. It started happening just recently - so I figured it was the cold weather setting in as well - I'll need to try letting it warm up a bit and see if that helps.

danno is correct: the ECU won't let you rev really high when the engine is cold. It's not very good for your engine so the ECU doesn't let you do it.

If the car is still not up to full operating temp, do not try to take it up high or get on it very hard. Mazda has a failsafe to help prevent this. by holding you below a certain spot until it is warmed up.

Now to scare you... ;)

Since the engine is made from alternating metals with the rotor housings being aluminum, this means that each metal does not expand or contract at the same rate. With normal warmup this isn't an issue. It's sudden heating that can really affect it though, specifically the aluminum rotor housings. Remember that the internal chamber temps can hit 2000*F at full throttle but due to the water jackets the actual housings may get up to about 400*F or so. If you get on it really hard and pass all of this heat out the bottom of the engine, but the top of the engine is still only at 100*F or so, that's a severe expansion difference in the housings itself. Aluminum flanges warp easily when welding due to severe heating so they must be done slowly to avoid this. Same thing here. Warm it up slowly. You don't want to replace an engine that blew a coolant seal from warping.

Cool, thanks for the quick response and easy explanation.

Can you get warping even though Mazda tries to prevent this by rev-limiting?
If it doesn't prevent it, then I think maybe rev-limit at lower RPM's or Mazda should think of a fix. After all, this car was intended to be sold to the expert drivers that will race with it at the track as well as the every-day commuter. Therefore, not everybody will wait until the car warms up.

There isn't an engine I can think of that you want to just drive the shit out of it when it is cold and not up to operating temp.

Anyone noticed that the rotary seems to be more powerfull low in the rev range when it is cold ?

Yes, you can still damage the engine if you make a habit of winding it up high (even to 6500 rpm) from a cold start. I don't think a fix is necessary as it's a bad idea to rev ANY car high while it's cold. This is something you should know as the owner of any car. Mazda just put the limiter there because the 8 is capable of heating up much more quickly, and to higher temps than your average piston engine.

Bottom line: give your car a few minutes to warm up before revving the crap out of it.

just to keep all everyone informed:

This car also drinks oil on a pretty regular basis.

What's that got to do with waiting for engine warm up?

think about it. when you get hot, wouldn't you like a drink?

:beer: