AAaF

I have rough response when going from fuel cut off and to where engine starts pulling. Or, if you like, from 0% to slight throttle. Its, not surprising, worst in 1&2nd gear, there it can start oscillating/jerking at low RPM.

If its of interest, it's also feels like very little power extra from 50->100% throttle, but I understand this is not unusual. Power is good though(225Hk estimated at flywheel, no CAT. For what its worth). 60k miles.

I have
- Changed spark plugs
- Cleaned MAF. Was covered in oil, and has most likely been for a long time before I checked
- replaced MAF screen(original was torn)
- tried different maps(original and MM, 1st and 2nd tune)

Any ideas what to do next?

AAaF

Boing!

twistedwankel

iTrader: (6)

The Mazda tech after a lengthy data search on car found the 3 sensor/solenoids controlling the drive by wire throttle positioners and the gas tank purge were all defective causing throttle response issues.

We also discovered the fuel pump was on it's way out by attaching a hard plumbed gage and driving the car over 5k - pressure is supposed to increase while mine dropped @ 5k to when the last injectors kicked in. I can feel the surge in power at anything over 5k in 3rd gear now.

I don't know how often you rely on the fuel cut out at 9300 where the water pump is cavitating over 8500rpm? I have a disconnected factory rpm buzzer but shift at 9k by ear prior to then. It's not good for the engine to keep doing that routinely and you aren't gaining any speed. You might want to install a shift light?

Hope this helps.

jasonrxeight

RX8 does not have dual mass flywheel and rotary engine has a lot of engine braking when off throttle.
it's just how it is. clutch in more when moving at low speed and lower gear.

AAaF

Thanks, I was suspecting some issue with the drive by wire system as well, but it seems like position feedback of throttle is correct at least, just looking at % with Cobb.

I dont understand what you mean by "gas tank purge", could you explain a bit more - pardon my english.

Not lacking power, so I do not think fuel is the problem. Lambda values are fine as well at WOT.

AAaF

Maybe, but subjectively i do not think it was quite like this when I bought it almost 5 years ago.

twistedwankel

iTrader: (6)

There is a sensor/solenoid that controls pressure inside the sealed fuel tank and releases fumes into the intake as needed. Mine was defective altering the mixture if I understood the tech right. Anyhow they replaced it along with two others.

jasonrxeight

another thing to consider is your fluids are thinning out due to wear so they don't soften the shock anymore. your bushings might be hardened or worn out sending more shock to the car. also your drivetrain is wearing down too meaning more back lash between teeth.

twistedwankel

iTrader: (6)

I was recently informed that my oil filled motor mounts are starting to leak at 74k.

So I got a new set from MazdaSpeed for 1/2 price = $204. Cost $500 installed by dealer = that sucks. I am aware that there is an angular adjustment for driveline too via mounts to keep things smooth with the driveline.

Had mine done once via Dealer. Will do again when new mounts are installed.

AAaF

The bushings/motor mounts might be a hot suspect, I have not checked these.

While logging WOT at 2nd gear I also get jerking at ign time lead coil, something i was told could come from vibrations in engine.