I just finished replacing the head and timing chain on my 93 22re 2wd pickup. I shorted the pins in the diagnostic connector to set the timing but it runs rough at 5 degrees before top dead center (TDC). The truck idles best at 20 degrees TDC. Also, I noticed that the check engine light continuously flashes when I insert the short across the diagnostic connector. Why can I not set the timing at 5 degrees TDC? Thanks and any advice is appreciated!

 

Your TPS sensor is not setup. Idle-E2 pins on the TPS (bottom 2 pins I think) needs to be a closed switch at idle. When you put the jumper into the diagnostic you should hear the engine RPM drop. If not your TPS is out. Without the TPS set up the ECU does not go to base timing.