Greetings fellow rotary heads! I'll do my best to keep this short and sweet.

I have owned rotarys on and off (all RX7's though) so my friends always come to me with rotary problems. A few months ago a friend of mine bought an 04 RX8 (104k miles) base model. At first it drove great but now he's having problems with it. Its just plain doggy! The idle bounce's between 500RPM and 1200RPM, its not overheating. If you come to a stop and don't leave your foot on the gas a little bit it will die but only when its warmed up. It start's fine when its cold but dose not like to start when warm.

As a mechanic with some experiance with rotary's my thought's are the TPS is out of whack, possible stuck/sticky apex seal, and clogged catalytic converter.

Its been a while since I have worked on a rotary so I am more than rusty but I have some questions.

1. On my FC's I used the "water drink" method(vacuum line from TB into a jug of clean water while the car was being rev'ed up) to free up apex seals and clear out carbon build up. Is it safe to do this on an RX8? I know its possible to clog the converter but that aside will it cause damage or anything "weird" to an RX8 over a 7?

2. Can he TPS on an 04 RX8 be adjusted and if so would one of you mind pointing me in the right direction as far as a walk though or similar? it was easy peasy on the RX7's and that's about all I remember.

3. Tips on where to geta new converter for cheap or what to replace the catalytic converter with? Its a bone stock car and my friend needs to get it back in daily driving shape asap so I'm going to help him out but I don't want to be the cause of death to another rotary. It ran perfect before he got a hold of it.

Thanks for reading my wall of text, in a normal situation I wouldn't post just lurk but time is of the essence and he is in need of some fast advice and help. Thank you all so much for your advice in advance!

 

You need to get off your Rx7 background, RX8 came out years later and it's completely different than ANY RX7 experience u had,everything is controlled with computers via CAN bus (computers) and there is not much you can do really.


1. You mean Steam cleaning, it's safe but u need to watch out it might break the exhaust sleeve and/or the CAT. even the exhaust sleeve is made of Inconel.
2. There is no such thing as TPS on RX8, can't you tell it's all electronically controlled ? can't u see there is no "cables" attached to the pedal from the "throttle body" ? so no you can't adjust it, at least not mechanically. reason why it's dying at warm is the same for ALL Rotary engine --- it's compression is LOW, Maybe a stuck seal but Unlike Earlier P-port Rotary engines, 13B-MSP actually having Stuck/worn out side seals, cuz of the Exhaust port location. and there is not much you can do about it other than a complete overhaul.
3. there are aftermarket converters, cost about 300 something bux. you can get them pretty much at anywhere online. Why is it so expensive? Cuz it's a 3 way CAT, thats why. No your 100 bux RX-7 FC cat will not work even u can somehow bolt it on.

Your friend's car needs a new engine, simple. well if he just past 100K (104K?) then u can go and beg Mazda to see if they would give him a replacement under the 100K/8 yrs warranty. sometimes it will work. especially he just got the car and tell Mazda how "disappointed" he is right now, engine just died right after warranty is over?

Another thing you can look at is the Throttle body, but you need a Computer to do that, don't think you have one. the sensor inside might be bad, if it's at the broader line of failing, it will not throw a CEL and you get weird idle issue. been there and done that.

b4 u bitch at me, yes I have RX-7 too, in fact, soon Im going to have 2 RX7. so I know the difference between the 2 inside out.

you are welcome.

 

I'm not sure how to reply to such a post.. Thanks?

However, I did admit I had little experience with the RX8, kinda why I posted to ask a question here (bad idea?) because I know they are totally different beasts under the hood just not exactly what make's them different.

That aside I haven't actually looked under his hood, he's a single father with no time so I only have the info from a few panicked phone calls in the last day. I assumed that the throttle was electorally controlled.. I think you could have left it at "no TPS on RX8's man..." no need to berate my lack of knowledge when I'm asking for help

However, I feel more confident that his rotary just has low compression now, I wasn't sure if any of the electronics's under the hood would simulate the same problems.. sorry

Compression test is in order. Thank you for your time.