The later 2 weeks I am experiencing rush morning starts with my 8. Temperatures in the morning i about 18-22 celsious.
The car now have 40,000km something.
Yesterday I replaced the battery but again this morning happened.
On 30,000km I replaced all coils and sparks.
When it starts is doing something like "boap boap boap" (like an old diesel machine :P)and it smells something like unburned gasoline but after 10-15 seconds is running smooth.
I didn't notice any power loss.
Ermm... 5-6 days ago it happened something like a flood, it didn't happened again. I was cranking for 3 times without sucess. Then I depressed full the throttle crank for 5 secs. And then crank without throttle and it started.
The mechanic who replaced the battery insists that it was a battery issue. In addition he suggested to use a Fuel system cleaner maybe the injections built dirt. I am planning to use the STP complete fuel system cleaner.
Anyway i hope that there is not anything that i shoudl worry about my 8.

 

Leaky injectors maybe?

 

at first i was not going to say anything but here it comes!!the mazda rx8 is in most cases like a very fine woman(don't hate me girls)you need to start slow and wait till she's ready to go otherwise she will turn into something you won't like.but take the time warm her up gently then run the hell outta her and she will love you forever and even be forgiving when you need it the most!!works for me and i'm happy as hell(with my 8)for the last three years and by the way 18 years with my girl and still havin fun!!!

 

Its written in the bible of the 8 about the morning/evening warm ups. No matter with the heck i have to do niddle should move to move my 8.

Anyway, i had the incident again and ended up with a clue.
Maybe is something with a thermostat or the air or the fuel management.
The car when its cold it needs to warm up. Right?
So the RPMS are about 2k or less. Right?
My car is trying to reach that 2k or something but i cannot.
Maybe is because the engine is flooded with gas or maybe because there is not sufficient air to set the burn.
Therefore the mixture of gas and air is failing.
That is because i have the bad bad smell of unburned gas.
Though, isn't it curiu that the car after 10-15secs is running smooth??

Thanks!

 

That is what the mechanic said.
Do you think "STP Complete FUel System" or similar product would work?

Thanks!

 

The car is in good health and running smoother than ever
Just for the records.
The mechanic told me that he cleaned the air flow meter and clean completely the air induction system. Something about a twister he said. I don't know..
anw.. the car now is running perfectly

 

Please ask him to explain again and then post here.

 

When I asked I insisted (just out of curiosity) to explain exactly what was the problem. He said what I report above.
Air flow meter cleaning.
Twister cleaning of the air.
Note that my car is stock.
To sum up he cleaned everything that has to do with the air induction.

 

After loads of reading (this awesome "wikirxedia" :P) I ended up that what the mechanic was talking about was the MAF sensor. The car doesn't throw a CEL at all


So now... that I know at least what he "clean" with the problem still there and getting a bit worse by the time, especially in mornings
What are the odds that while he was cleaning the MAF he messed it up.

So...
Would a damaged/faulty/messed MAF sensor cause rough morning (generally when it is cold) IDLE?

Connecting the above with the following (PLEASE CORRECT CAUSE THAT WOULD BE A NIGHTMARE TO MY WALLET)

Damaged MAF sensor caused bad air/gas mix ratio.
Loads of gas caused the Sparks to fail which subsequently caused the coils to fail
and finally the non burnt gas caused the catalytic converter to gone ( i went to another shop and have the check my cat with the emission system it seems to be OK but I have to take him out and observe, that seems to be the best method) ...

Does this make any sense?

Best Regards,

 

Which viscosity oil are you using? Here in Detroit, when it gets to zero or below, I have the same noises even while using 5W20. I may switch to 0W20 soon.

 

I am using Repsol's mineral 10W 30. I used to use Kendall's hi performance mineral 10W 30.
I am experiencing this issue since summer. Here in Cyprus is very hot (between 40-50 Celsious). Now is winter and is about 18-22celsious.
Hmmm....
Maybe I am experiencing this since I changed oil brand?
Is that possible??

 

Yeah, my bad. I glanced at the C and thought "F". The ignition coils are thought to go "bad" around 25K miles. Maybe that's the problem with burning those rich mixtures. I would start by cleaning the plugs(but I think you may have said your mechanic did that already?) with carb cleaner and an old toothbrush. No point in spending money for nuthin'.

 

Finally......

I was suspecting the CAT and I got it replaced with a straight pipe. First impression is just wow... My cat doesn't seem clogged or any damage but the car makes a difference (my butt is not dyno as MM say :P) though i feel the difference (placebo maybe :P) The smell though is very very very bad.

Anyway... the problem persisted (cold start rough idle) and after exhaustive reading on the forum and car's workshop manual I found out that the AIR PUMP is pushing air when the car is cold for to bring the cat to its operating temperature.
So.. I just unplugged the upper plug of the air pump and the problem dissapeared.

Now... I didn't understand though wether the air pump is there only to warm up the cat. Therefore if i am running without cat i don't need the air pump am i right?

Thanks for your input

 

What's a "twister cleaning" ?

 

Maybe is the "butterfly" of the the throttle body. It is hard to get some words from my mechanic, he never explains what he does, he is throwing some words...

 

as for letting the car worm up i think it is a great idea, anything you see in the owners manual written basically on every other page, i really think you should follow :P. i have pulled my parking brake down many times to push the car out of someones way rather then start it.

ex: woken up at 7 am this mourning (went to sleep at 4) rather then starting it i pushed it onto the side of the road...did i look stupid yes i was in my pj's do i care no.

after doing all this i still had to take my car in to get a new intake setup because of the infamous yellow/white crap on my dip stick. small prices to pay for having such a awesome car i guess