Stevemd24 Posted February 9, 2013 Share Posted February 9, 2013 Driving on my way home I had made a stop at the store and came back to start my car to find out that it went into limp mode, the car starts and stops just fine, and idles fine, but when hit 3500 rpms is just craps out on me it is a 240z 1972 with RB20DET / 5spd Transmission Rb25DET Turbo Nistune, Type-2, board the computer is not giving off any codes, and i am having a hell of a time trying to figure out what is wrong with it... Can anyone give me any suggestions Thank you for your time and input Quote Link to comment Share on other sites More sharing options...
pat1 Posted February 9, 2013 Share Posted February 9, 2013 My guess would be either the CAS or the airflow meter. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted February 9, 2013 Share Posted February 9, 2013 Id say you are not experiencing a limp mode, but a failure which is where you need to start your diagnosis. If the ECU has not set a code you are definitely not in any kind of limp mode. Id say the ecu has NOT detected a problem and is simply running with the values its being given at the moment. I too would suspect airflow meter(or vacuum leaks) and then the CAS. Are you making boost before it craps out at 3500rpms? Quote Link to comment Share on other sites More sharing options...
Stevemd24 Posted February 10, 2013 Author Share Posted February 10, 2013 (edited) the cas and maf have both been changed out and tested, did not fix the problem, I thought it should be a sensor but its not coming up in the trouble codes or checking everything with an osciioscope, at this point i am looking into the nistune software... but i am grasping at straws at this point Edited February 10, 2013 by Stevemd24 Quote Link to comment Share on other sites More sharing options...
pat1 Posted February 10, 2013 Share Posted February 10, 2013 (edited) With the engine running look at the fuel trims and the o2 sensors what are they saying rich/lean. What ignition timing are you seeing with it starts messing up. Look at the engine cooling temp and intake temp. Are they showing the correct temp? I had a ecu crap out on me on my 20 before. Are te caps in the ecu ok? Are they leaking? What's your fuel pressure? Is the cam/crank timing ok? The NIStune is a pretty sweet setup you can monitor everything the ecu is doing. Edited February 10, 2013 by pat1 Quote Link to comment Share on other sites More sharing options...
Stevemd24 Posted February 11, 2013 Author Share Posted February 11, 2013 Thanks for the ideas got to wait for the weekend dam real job gets in my way Quote Link to comment Share on other sites More sharing options...
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