| side under foot rug there is a plywood panel. Remove it 4 bolts. Look for slit screw on right side of computer. Turn ign to full dash lights on position. Turn ECU screw CW hold for about 5 sec then CCW to the original position. Codes start flashing in sequence on Check Engine Light (CEL), first long then short flashes. Count them and get a list of what they mean from the FSM below or on this site. Code 55 is all clear but some issues are not covered in codes especially early Z32. Codes do not generally indicate a problem with the component as other issues will cause a code to be listed, like vacuum leaks will trip an O2 code, etc. Check components before replacement they may be OK. To leave the code sequence setup while in code read mode just turn the ECU screw CW hold about 5 sec then CCW. However from the code read mode you can check the O2's by starting engine in the code read ECU mode, then do the CW- CCW screw turn and place the WARMED UP engine at 2000 rpm and CEL should flash 5 times or more in 10 sec for the left O2 to pass that test. To check the right O2 repeat the CW- CCW screw turn again and repeat the 2000 rpm test. When done just shut off the engine, restart to make sure ECU is back to normal setting. To further test O2's even if they pass the above test you need to use a digital VOM at the connestor to read the voltage as the engine is at 2000 rpm. To be good they shouls alternate from about 0.1V to 0.9V. If they stay close to 0.5V no good. The heater section of the O2 can be checked with the ohm section of the O2 connector (engine OFF) disconnected. read the FSM below. With the Z32 and being a DIY further reading in the FSM here: [ http://300zx-twinturbo.com/cgi-bin/manual.cgi ] Check your car for vacuum leaks and other issues, also check the coolant temp sensor and thermostat for correct coolant temp (see FSM, if incorrect temp the ECU will run the engine rich if to cold and keep the car in warm up mode and waste fuel not good) I check thermostats in place with an infrared temp gun near the thermostat. If bad I recommend the Nissan unit over after market ones. Check the PCV valves and replace with Nissan unit and hoses if bad. Check with a vacuum gage hooked to plenum start engine and open the oil filler cap to see if the vacuum drops 0.5 to 1 mm Hg if ventilation system at least working. Also vacuum needle should be rock steady reading at any held rpm for an engine in decent shape with no leaks. See testing with a vacuum gage for further info. [ http://www.atlanticz.ca/zclub/techtips/vacuum/ ] Get back with questions.
ZUL8TR in Orlando,FL |
01:49:15 01/15/14
