my 1988 mazda rx7 idles at around 5700rpm. I know this is not good and don't know how to fix it. Any comments would be very much appreciated.

 

Have you checked for vacuum leaks?

 

yes. I'm thinking its the idle air control valve but I'm not sure.

 

5700rpm sounds too high to be related to the BAC or cold start/thermo wax. If those systems were the culprit, you could expect an idle closer to ~3000rpm.

Silly question, but have you confirmed the throttle is not being held open (tension on the throttle cable, stuck cruise control cable, stuck OMP rod)?

 

well the throttle isn't stuck. From my analysis today, the plunger under the throttle isn't hitting the metal part under the throttle and I think it's supposed to. When someone presses on the plunger the rpm fluctuates and can get it to around 1500. Gonna try to rig something up so I don't have to replace the TPS. As for cruise control, I don't know if my car has it. I'm not sure what an OMP rod is.

 

Do yourself a favor and download the factory service manual (FSM), if you haven't already. It had procedures for how to set the throttle body, TPS, etc. it's free, and available from multiple sites. This is covered in several stickies on this forum.

Cruise control would be easy to identify, you would have a second cable attached to the TB right next to the throttle cable.

OMP is the oil metering pump. On the S4 (which is what you have), it is mechanical. A rod is connected directly to the throttle body and actuates the pump based on throttle position. This system can stick and cause a high idle.

 

thank you very much!