jonr-

hello! I've got one , hopefully easy questions..

:

when I drive my car i 1. gear from 2k to about 9k rpm, I feel like the motor is struggling to go "smooth" all the way up to the redline. I mean, not all the way, but in some areas.

from 0k - 3k its "ok- smooth", but from 3 to 5500rpm its like an "on and off" struggling to go smooth.. dont know the english word for it.. its not 100% similar to real bad sparkplugs, but its still a motor that dont go 100% clean.

a better explanation is: the engine is simply holding back a little bit.. The "struggle" dont make any bad noises from the exhaust, neither does it make the car shake or jump.

and of course when Im passing 6k its a little bit un-smooth, but thats becouse its opening some more ports (or something like that). with other words - its normal.

When Im in 7k to 9k its feels like its no problem at all.. at least its much more smoother than it is from 4k to 5500rpm.


"edited": important info is that this is NOT with the gaspedal fully in.. I have the gaspedal slightly in so that its like 0-60 kph in 6-10 seconds.. When I have the gas fully pressed, its not easy to notice this problem at all.. strange?


In 2. gear and the rest of the gears, I cant seem to notice this problem.. Its just in 1.gear its easy noticeable

Edited: It's actually possible to experience this problem in 2.gear to, but with a a much lower "problem - intensity".


Why is that? this little problem is killing me... It makes me think that I lost some power and makes me think stupid thoughts like "the car wont go as fast as it once did" bla bla bla..
Usually I have tendencies to think the car are loosing power after I have "gotten used to the number of horse power when Im driving"... (this might be hard for you to understand- the way I write,I mean). - when talking about horsepower - much want more.



I really hope someone got a good answer for this one...

rotary.enthusiast

There are small dips in power when the extra intake ports open up at 3750 and 6250 RPM. The dips in power are very small, but first gear is so steep that you can feel them pretty easily. Could this be what you're describing?

nycgps

iTrader: (1)

how old is your car again ?

It could be your fuel pump. they're known to fail prematurely.

mine started to give me problems when I was maybe 35,000 miles. I finally replaced it myself @ 43,000 miles. no more "choke/not smooth".

jonr-

this is describing almost 70% of my problem! but one thing thats sad, is that it also happens in the whole register from 3750rpm to 5500 rpm..

so therefore it might be more like the problem mention under.

thanks for a nice answer though.

jonr-

its a 2004, thats gone 43 000 kilometres, thats about 25000 - 30 000 miles i think.

So... I may have to change the fuel pump...hmmh.. can u describe a little bit detailed? U said it chokes and not will go smooth with problems with the fuel pump.

nycgps

iTrader: (1)

in normal driving, your butt dyno should not feel any dip in power.

First off do you always wait until your fuel pump light to turn on(very low fuel) before you Re-fuel your tank? if u do, your pump will die a lot faster. *Even if you dont, the stock Fuel pump suck, probably last another 10-20 miles before its giving you problems*

This Fuel pump has 2 modes, one is low and the other one is High (duh...)

If it has a problem, when in "high speed mode" the pump might not be able to provide enough pressure for the needs. So the result is, your engine has not received enough fuel. AFR rate gets super lean and u will feel the "choke" at any RPM after 3750.

oh try this, go find a long road, Go like 6-7,000 rpm, let your gas go for a second or 2. then Step on it Fully again until 9000. if you feel ANY choke. your fuel pump has a problem.

Outkast187

coils can do weird stuff like this as well, but start simple first. Plugs/wires can also being going bad, I have had them do odd things as well that I wouldnt have guessed (run fine at certain RPM, and not at other).

jonr-

hmm... the thing is that the car dont choke/go un-smooth when I hit full gas. its only when I'm driving like grandma up to the redline.
Im going out and re-check that now, but Im sure that I wont feel any choking when I rev i up.
that should be a good thing, right? :P but still im hoping that it isnt anything wrong, and its all in my head, but this time Im pretty sure it is real... buu huu

jonr-

this is annoying! I really hate it when my cars wont go 100% clean.

As far, this is the final conclusion:

My car/motor is kinda holding back when I rev it up slow and easy in 1.gear. I can also see/feel the same symptoms in 2.gear as well.


When I rev it up with full throttle, there's almost impossible to notice the problem.





Is there any solutions to my little problem?

could it be a "medium- dirty" maf sensor?
I dont wanna clean it if its not necessary.. with my luck It may do things even worse:P

could it be spark plugs? - shouldnt that also make choking when I got full throttle as well?



- jon

nycgps

iTrader: (1)

then its probably ur cat.

jonr-

my catalysator?

if so, im pretty sure its a minor exhaust leak from the cat (or somewhere near the cat) , but I asked a mazda mechanic, and he said it was normal, but still I doubted it...

so that could be the problem?

nycgps

iTrader: (1)

have you check the coils, plugs and wires ?

when the mazda tech check ur cat, did he take it down and look at the inside ?

jonr-

no.

it was like this:

- hello! mazda mechanic. is this an exhaust leak?
(he comes besides the car and Im starting the engine and rev it up to 3000rpm. (the exhaust leak is only "hear-able" when I rev it up and its on its way down passing about 2000rpm. then U hear a little "farting" sound.

- welL! thats just normal he answered.

Thats why I hoped the leak was just in my head.. but apparantly its not... im like 70% sure that its a leak



so.. a little leak in the catalysator will make you're car go "un-smooth" ? I didnt know that... but its sure many other things I dont know either.. so.. :P

Outkast187

No, an exhaust leak wont do that. No service engine light on?

nycgps

iTrader: (1)

an exhaust leak wont bog ur car down. think of running a car without exhaust, more free flowing, u think it will bog the car down ?

its either ur CAT going dead or coils/plugs. Worst case is ur engine is simply bad.

Outkast187

If the cat is bad, it will usually have a rotten smell to it when the car is running. But, if it revs out clean at high RPM, its not likely its the problem.

Could be bad leading or trailing plugs or coils, that would explain why it runs better at certain RPM.

nycgps

iTrader: (1)

I had a clogged cat b4, I had no rotten egg smell.

got that smell after the CAT completely burned out tho.

if his tech said its not cat, then maybe have him check other stuff.

jonr-

I dont understand...?

CAT = catalysator in the exhaust?

or is "CAT" something else I dont know about?


Becouse, ur keep telling me that the CAT might give me the problem.. ?

?

And worth mention:

its not like its the engine thats poor - i really hope.

dont you guys think its strange that I only can experience the engine "holding slightly back" in 1. gear, and only with the gas pedal half in (50% full throttle). `??

If it was anything wrong with my engine, I should experience this problem in all gears? especially in higher gear with FULL throttle all the way to 9000rpm? dont you think?



and.. I've also experienced bad spark plugs, but its not fully comparable with this little problem I've got now.. neither is the coilproblem I also had on one of my 200sx for while ago...



and just for repeating myself, again, : this is not like the engine is holding back/bug/choke big time, it is actually likely that if my dad tryed the car, he wouldnt notice - at least not within the first 5 minutes... (its not worse than that, just to get things in a little perspective.


woaw.. this is making me nervous.. hehe.. and my visit to the mechanic mazda isnt before 2 weeks.... thats to long with this problem making me insane :P

thanks for all help though

Spinning Sushi

iTrader: (21)

Yes, CAT is short for the Catalytic Converter. It is what you referred to as the Catalysator in the exhaust in your previous post.

neXib

Well in my opinion the RX-8 has a pretty sensitive gas pedal, so it will jerk a bit sometimes if accelerating slowly in 1st, but it shouldn't hesitate.

My solution is simple, if it only happens when you drive slowly, stop driving slowly :P

shaunv74

This problem is consistent with bad coils or plug wires/plugs.

Change your plugs, wires and ignition coils and you'll be good as new.

jonr-

=) are you sure that's the problem?
It coulndt be a slighlty leaking cat thats making this?

rotary.enthusiast

The thing that I find odd is that if it were either the cat, or coils/plugs I would think that the problem would be more pronounced at higher RPMs, but you say it runs fine from 7k-9k? Still, an ignition problem is the most likely culprit... the first thing I would do is pull the spark plugs and see what they look like.

jonr-

yeah.. I think thats strange to...the motor never struggle anything at 7 to 9000 rpm. its around 3-4k and 5-6k rpm the trouble comes.

perhaps its the ignition problem, but still strange that it wont make problems with full gas....

If it where as easy to change plugs on this car, like it is on any 200sx, I could have done it within 10 minutes, but to be honest.. i'm actually not 100% sure where the plugs is in this rotary engine.. (yes, i've tryed to understand the DIY "how to change spark plugs".) - and yes, im not a mechanic..

and I cant seem to wait for over 1 week to the day I have a schedule at the mazda mechanics...Im not even sure they can check this problem at my schedule either..becouse they are going to change my bearing in the transmission on the warranty.. dont know if they got time for it..


again. thanks for good answers.

jonr-

still hoping that someone that experienced the same as I describe, would give me an solution, or at least give me some comforting facts regarding my !hopefully! - insignificant problem!





.............oh man... this is killing me:P why cant I be like everybody else, and just accept and realize that its a problem with my car and live on without even think about it once.

I think about it 3 times each hour and its starting to be irritating:P