Hehe, I'm new to rotaries, new to the forum and started fixing up cars half a year ago (started on my 91 S13). Although I could say myself I'm mechanically inclined. I just got my 1989 GXL S5 FC half a week ago, clean body, clean engine (beautiful machine ). Got the car in limp mode and only experienced what a rotary can do once but the fun soon ended.

I did the procedure to get CEL codes and only got code 20 so I'm pretty sure its the OMP position sensor. Checked the OMP sensor through the FSM's procedure and it seems like the OMP sensor is fine. I still have to double check. Vc and E2 give 900-1000 ohms, Vo and Vc give off 150ohms. Together they do 1050-1150ohms. Sometimes when my engine is cold the CEL would flash or wouldn't turn on until a few seconds or minutes.

Yesterday I jacked up my car from the differential to check out the open diff for the hell of it. I put my car down, start my car, and looked forward. I saw the CEL off to my amazement. In fascination and excitement I drive my car down my neighborhood street not in limp mode for the first time and loved it (makes my S13 look like garbage ). About 10 minutes later, it comes back on and the fun ends.

Anyways, I have yet to check the ECU and wiring harness (which I will do after I post this). I was wondering if driving it around in limp mode was safe. Do I have to premix? What other areas could I diagnose? Even though I'm throwing the position sensor code, could it also mean a faulty OMP? What advice do fellow S5 FC owners have?

 

check the harness/connectors for the omp.i wouldn't drive it when in limp mode since there is little to no oil going to the motor.if you have access to another omp then swap it out.