as a gm mechanic confused is what i am.my sister in law gave me an 88 rx-7 when she bought her new car.it has 50k on it and runs but runs like doodoo.she told me that the dealer told her that the something shaft had broken and that is why the car ran poorly.the shaft apparantly connects the 2 rotors to the flywheel to the trans.so my question to all you folks is how likely is it that this is true?put the key in and turn it ,it starts.all the accessories work.a/c alternator etc.all the belts spin.put the car in gear and it goes forward and backward.this leads me to believe that all is still connected in there.i am not a rotary mechanic however.so can i pull the plugs and check for compression like i would on a gm?do the normal diagnostics work for a rotary?what is the most likely cause?thanx in advance for the help!!!!!!

 

The chances of breaking the eccentric shaft are not very likely at all, what issues does the car have? What does it do/doesn't it do?

 

50K miles is low. Hopefully it is something simple.
Pick up the $15 Haynes book and do some reading.
Exactly what shaft did they say was broken? Or is it the service managers common quote-- "we don't know, so tell her that she needs a new engine"....
Get a compression check from the Mazda dealer or any shop with a rotary compression checker. Don't go to the dealer that diagnosed it broken. There might have been newbie mechs there. If all six(3 readings from each rotor) are in spec, then give the car a good tuneup.
Spark plugs, oil/filter, air/fuel filters, thermostat(mazda), vacuum hoses replacement, timing/idle set, TPS set, FI cleaning.......

 

Sounds like he's blowing smoke up your butt
I say u get a new engine..hell u gotta pay something for getting a free rx-7.

 

What does that mean in technical terms?

The eccentric shaft in the rotary engine is like the crank shaft in a piston engine. It wouldn't run if it were broken. It must be something else.

You can download the entire factory service manual at the below link which also has some other good info. It's pretty big, so save lots of room on your hard drive. The 88 manual is under How-To's/Manuals.
http://fc3s.org/

More stuff for RX-7 newbie mechanics:
http://www.teamfc3s.org/main/articles.php
http://fc3s-pro.com/TECH/tech.html
http://www.iluvmyrx7.com/
http://www.mazdatrix.com/

 

the car does everything it is supposed to but runs roughly.the best i can equate to is a piston engine that drops a couple of cylinders.it just runs rough with lack of power.

 

That can be a number of things. Does it rev up fine to a certain point then have issues? And the rough idle, what does it do, not want to idle, or does it hunt up and down? Also, does the car have any troubles starting, or does it start right up?

 

the car starts quickly,idles rough but does not hunt up and down,will spool up rpm but is not responsive,takes afew seconds to build.makes no banging,clanging,loud or obvious noises.has exhaust exiting both tailpipes[although i dont know if there is a y or balance pipe under there so this may not be relevant] thanx for all the past and future help!!!!!!!!!!evil aviator thanx for the sites you left me they are excellent!!!!!!

 

Take both bottom plugs out. Place your finger on the front hole and have someone crank the engine. Feel the pulses of that hole. Now do the same with the rear hole. If you have a broken apex seal, you will feel the difference b/t one rotor and the other. If you have a busted one you won't have to ask what a good one feels like verses a bad one. You'll feel the difference. Prior to doing the above it might be a wise decision to pull the EGI fuse or pull the little white plug off the cas.

 

An 88 with only 50K. Sounds like a good candidate for the ATF trick fix.
Bill

 

i'd do a full tune up like was previously suggested. and adjust the tps. run some MMO in the crank and the tank. and see if most of that doesn't go away sounds like just a lot of carbon build up.