sorry if its a newbie question but...............

tonight i messing around with the rx, its an 88 turbo 2.... just trying to run through the gears, and from 2nd on i hit full boost and then once i hit about 6 grand it wont rev past..... i cant max out revs....... is that the fuel cut kicking in....... its still at stock boost but wondering whats going on? any suggestions.......... the car seems to be running really rich as well..........

 

Elaborate a bit. Does it just completely stop accelerating at 6k, or is it just weak? If you're running stock boost 5.5 PSI on an s4, you shouldn't get a fuel cut on the rear rotor. (only happens above 8 PSI I think)

 

i think it was fuel cut, my actuator arm was disconnected.........

 

Your wastegate actuator arm being disconnected will keep the boost from building quickly, if at all. It sounds like your TPS. I had the same exact issue except at 6500RPM. It wasn't reading WOT right, despite passing the spec test I did on it the first time. I checked it later and found it was a little off, so I replaced it and now I can redline all day. However, if you can pass that RPM under light throttle or not under boost at least it may not be your TPS, but you should check it and start looking for a replacement. They're usually pretty cheap used, I got mine for about $25. Even if yours tests out fine it may still be bad. It's happened before.

 

hey thanks , i'll check it out, it is still doing it, and mine is at about 6500 rpm as well.....

 

Did anyone ever figure it out?! I have this issue as well right after i installed a new radiator. 6.5K rpm.... WOT, manifold pressure reads 6 psi and cuts to 25 inHg vaccum immediately. No clue why this would happen after a radiator install. Is it really just a TPS problem? ive replaced mine this year already.

 

Was it a used one? A used one may be good, may not, or may be near death. I think I was fortunate to get a good used one, but I guess I can't say how many good ones are left out there. The point is, even the tests can be misleading. I tested mine a long time ago and it seemed to pass, but like I said I tested it later and it seemed just barely odd, so I replaced it and my RPM wall was gone. If I ever get the money and need another one I may spring for a new one (if any exist).

 

well, i am very picky about parts for my car and thus, purchase all new parts (even new fuel injectors) from mazda competition (www.mazdamotorsports.com) at cost. so yes, i bought a brand new TPS sensor and adjusted it correctly. I'll re-adjust it just to be sure. By the way, i had my old injectors cleaned by RP and that just worsened the 3.8K hesitation. Tripoint explained to me that cleaning will not repair the worn out tappet seats and that new injectors are the way to go. Shelled out the 1K for new injectors and now my engine is as smooth as an rx-8. also i can rev it to redline as long as there is no boost (i.e. part throttle). if anyone has done everything possible to get rid of the hesitation, shell out the cash and buy new injectors...

 

oh a new TPS from mazda comp is $125, if i remember correctly