Unable to rev, lack of accelerator pedal response
 

Hi, I am fairly new to this forum and do not know if this has already been answered or not but it's worth a shot..

I have a 2005 Rx8 70471 miles all stock 6spd manual....I recently had a belt snap and took it to the dealership via a tow truck to have it repaired, after the repair I have noticed immediately (on the way home to be precise) that when I press the accelerator the car will not go! It is strange, it idles fine and doesnt sputter or have starting issues... Just putting it in first gear and giving it gas it takes approx. 15 seconds to hit 10mph and stops going around 3k rpm, then shift to 2nd and it gets upto 20mph or so but acts like its pulling a huge hill with no power and also won't go above about 3500 rpm! It's showing a CEL but i have had it checked on 3 separate machines all showing no codes! Any suggestions?

P.S. also will not rev above 4500 rpm even while idling in neutral...

sounds like you went into limp mode'
When is the last time you changed plugs/coils? Check your CAT to see if it glows red after a hard drive.

Plugs changed about 200 miles ago, had new coils put on with the belts that I just had put on, probably should have added that in.... I had the CAT checked with an emmission inspection at local mazda dealer about two months ago and they said it was fine, of course it has been sitting most of the winter so any of that could change...

Check the wiring to the MOP...the belt may have taken out the plug when it went off....

Tháts what i think is going on with mine....Goin to adjust that switch today and find out....

Check the wiring first. Otherwise you could end up with 2 problems at once...... The positioning switch is a bit more protected than the wiring for the the stepper motor. The poisitioning switch should have a white paint hash mark on it

Make sure the scanners you tried to use are running the CAN protocol and not just OBD. If they are just OBD capable, you won't get a reading. If the computer triggered a CEL, and the CEL is still lit right now, there should be a code stored for it. If the CEL has now disappeared after a couple of drive cycles, then no biggie. If the CEL is still there and you cannot get a reading on the triggering code with a good CAN protocol scanner then your real issue may be the computer itself.

Ok, well for one I can't quite place the MOP or any of its wiring as I know little of these engines...but a few things I did notice, the vacuum hose on top of the rubber boot between the air box and the intake is broke, but taped back together, and also when the dealership put my new coils on, they cut one of the bolts that holds a coil down and didnt replace it so there is nothing bolting the coil to the plate that it is on, although it is still plugged in....would either of these throw the car into limp mode? also, when i first start it a few times I have been able to rev normally, but it makes a backfiring type of noise very slightly from the exhaust and it is louder than normal, but then it falls back into limp mode....

Disconnect battery....wait a few minutes....start car....if it revs ok for about 3-4 sec and then goes back into limp mode my bet would still be the MOP

I highly agree with you, this is exactly what mine did and the cam position sensor on the MOP was bad.


but you missed a step, make sure you reconnect the battery before you try to start it......lol just messing with ya.:boink:

finally found diagram showing MOP, checked connectors, its hooked up but its all rusty down in there, my guess is when the belt snapped and the car got slightly hot, the overflow must have slung some antifreeze on the connectors and probably tossed the MOP out of commission....dammit, i really didnt want to have to spend that kinda cash fixing it!

quick update.......i know it has been a while.... manufacturer didn't cover the omp after all :( But I fixed it, RX-8 running better than ever, new plugs, new coils, new intake, new belts, new pulleys, new OMP with 12k mile warranty on that, exhaust coming next month.... Looking good so as I can tell, still need the gas cap, but as we all know those are common as can be......side note, do NOT use castrol oil in your Rotary it CAN tear it up!

That's what i use...how come? Can you explain the theory about the castrol oil. Just curious.

Do you have any evidence to support this claim?

All I know is that the two rotary mechanics on staff at the largest mazda dealer here in kentucky, the mazda service manager, and one of the service managers at a different mazda dealership all confirmed that there is something castrol puts in their oil that does not very well agree with rotary engines and they do not recommend anything castrol for the wankel if I want to maximize engine life... I always bug them with questions just because I wanna keep mine alive as long as possible....They actually recommended either valvoline or pennzoil which I usually never used on my other sports cars, I always used castrol, but I listen to the rotary guys because it's kinda their obssession. I hope this helps!

Yeah I guess, was hoping for more than anecdotal evidence though ;)