pamdam

Hi my 8 has been a pain in the ***, i bought her a non starter with a new engine so far i have replaced;

The coil packs ands leads
spark plugs
Metering oil pump
maf sensor
removed the inlet checked for leaks and reassembled
replaced CAT and both O2 sensors
compression is good

there is a slight oil leak but nothing big.

Can anyone help with why my 8 is running rough still?

There was a missfire code which has now gone since i replaced the bugger MAF and Temperature sensor.

So no codes no lights drives like a dream but wont sit still nicely.


thanks

Cliffjumper126

There's a lot of things it could still be. I'd suggest you do a search, there's a thread that lists stuff that causes rough idle/msfires..I also suggest you look into your ESS sensor

pamdam

Thanks none of the other threads really help thats how i have got where i am now with all the other bits done.

just an extra note it idles at 800 rpm which is low.

HiFlite999

iTrader: (2)

Have you done the "brake stomp" ESS reset? If not, do that and see if it improves after a few drive cycles. If it doesn't, dismount the crank position sensor and clean it and the electrical connections leading from it.

pamdam

I have done the ess reset afew times thus far but only once since maf sensor replaced, should it need doing more than once or should the car just pick up on it?

I will give it a go taking it off sometime during the week.

anything else? i will literally try any thing accept dancing around it naked gave that a go aready and nothing sadly.

Cliffjumper126

Yeah the ESS (aka crank sensor) is what was giving me issues..just clean it and clean the connections and see if it helps. Is 800 low? mine idles at 750-800.

pamdam

really i thought it should idle at 1000 if 800 is ok then perhaps its not the idle that is a problem could be the engine mounts especially as the garage who put the new engine in for the previous owner didnt know their ***** from there elbows.

pamdam

I am still having a problem! Still getting misfire 0300 or p0301 or 0302 different each time i check. Also showing lean condition post cat code aswell on occasions.

Smoke from surface of the new cat. Also i have slight oil leak down the back of the engine and moisture in my oil but loosing no water at all?

This is really bugging me now as ive been on for. Month and no change.

Any help would be very welcome!!

wcs

iTrader: (2)

What year and model is your car.
Can you post the compression numbers, please.

800 rpm is the correct idle speed

Have you check the motor mounts. A bad motor mount will cause a rough idle, you know all shaky and lots of vibration.

What is it you are determining that you have a rough idle?
Noise, shakes, just the misfire codes you are getting?

Can you post a video?

edit:
Lean condition post cat would mean either the cat is bad or the sensor is bad.
Did you replace the cat with a OEM replacement or use some other solution?

pamdam

it is a 54 plate 231psi.

the cat was replaced with an aftermarket one the company good rep so i dont believe that has a problem and the o2 sensors were also replaced.

I dont have compression results as i havent tested yet as im hoping its not that coz it was a new engine. And the testers for rotary are expensive and so is the labour at mazda. it is a last resort.

during idle the exhaust pops and the car shakes also the needle move up and down slightly its not consistant.

Also the car misses between 4200 - 4700 rpm. this is a violent jerk when it is cold and almost unoticable when its warmed up.

pamdam

with regards to the misfire code i have been told that these can be erased with a normal obd sensor but unless they are done the devise used by mazda they will stay stored in the ecu and will comeback even though there may be no fault, is there any truth to this?

NV RAM code or something need to be done by mazda??

wcs

iTrader: (2)

I don't understand what a 54plate 231psi is?
You mean 231 high power model?

Still sounds like the Cat isn't up to handling the RX8 emissions, it's part of the reason the OEM is so expensive.

Pops and jerks sure does sound bad .. what kind of ignition parts did you buy?
I hope they are Mazda parts.

I'm not trying to be nasty but if you can't afford a compression test then you can't afford this car. The RX8 is well known for it's high cost in maintenance.

You mean a ODBII Scanner and yes most of them can and I believe the Android Torque app can as well. You need a bluetooth odbII dongle device to go with it.

You can clear the code as well by disconnecting the battery and then holding your foot on the brake for a minute. Then wait a few more minutes before reconnecting the battery

No I don't believe there is any truth to that statement (if I understand it) but I'm not a Mazda Tech so I don't have access to all their fancy stuff.

NVRam can be reset by using the 20 brake stomp procedure.

pamdam

i can afford the test thanks, however i would like to avoid it if it is not required. the other parts are all mazda the sensors the plugs and the coil packs.

They arent that expensive to be honest but cost needs to be kept down on this one as i bought it to repair and sell on. I have another which is mine and has no issues.

its is 54 plate which means it is a late 2004 mazda rx8 and yes 231psi means it is the 231 high power model.

the exhaust fumes are coming out in bursts not constant it doesnt make a popping sound and the car is shakey and vibrates.

I know it sounds bad hense why i need some helpfull information on what is could be.

simply put the car is vibrating at idle and the exhaust fumes come out in puffs, there is a misfire code and the car misses between 4200 and 4700 rpm but only when in gear.

anyone who has helpful tips other information is listed throughout the thread so far.

pamdam

could this be a stuck ssv??

pamdam

Oh and yes of course i mean obdII but i didnt think i needed to say that i plugged my blue tooth obdII scanner that i bought on ebay and i connect to my samsung galaxy sIII mobile phone and use it to read and clear fault codes. as it is abit long winded? As this is a forum about cars i assumed people would know what i meant sorry.

nycgps

iTrader: (1)

so many noobs ... who just wanna spoon fed them ...

what happened to humanity these days ? ...

pamdam

I hope the spoon fed comment is not aimed at me as i have been the only one in my own thread where im aking for help from others actually posting ssuggestions as to what the problem may be, sorry for thinking this was forum for technical advice.


If had known it was a ask 20 pointless questions and give no help forum i would have posted else where. lol

Can anyone who is able to give me helpful advice please feel free to post I and not a noob I am experienced in other forums such as vpcuk mx5 and bmw and they are all most helpful with my other cars.