Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Normal
First gen NSX as in NA1/NA2 versus NC1 or do you mean pre versus post OBDII?On a pre OBDII car there are probably ways that you can block the ECU from generating an error code when you delete the EGR valve. Later OBDII cars have a lift / position pot and that might be harder to fake. However, that might be the least of your issues. When the engine is in the EGR operating range it admits exhaust gas to the intake manifold which reduces the available O2 for mixing with the fuel. The fuel maps in the EGR range are adjusted to reduce fuel PW to keep the AFR at the target value. When the ECU gets the message that the EGR is not working I expect (but am not 100% sure) that it switches to a back up fuel map based upon no EGR so that the engine is safe and generates a CEL saying that there is a problem. If the ECU does not detect an EGR failure because you have tricked the EGR monitoring circuit it may not map switch leaving you with a lean AFR engine condition which is undesirable.If you are prepared to rewrite the fuel map to adjust the fuel PW values in the EGR region you can eliminate the lean fuel problem and do the trick to avoid the CEL. [USER=18194]@Honcho[/USER] has remapped his NA1 ECU and I believe is running with the EGR deleted so he can probably give you better advice on the complete solution.
First gen NSX as in NA1/NA2 versus NC1 or do you mean pre versus post OBDII?
On a pre OBDII car there are probably ways that you can block the ECU from generating an error code when you delete the EGR valve. Later OBDII cars have a lift / position pot and that might be harder to fake. However, that might be the least of your issues. When the engine is in the EGR operating range it admits exhaust gas to the intake manifold which reduces the available O2 for mixing with the fuel. The fuel maps in the EGR range are adjusted to reduce fuel PW to keep the AFR at the target value. When the ECU gets the message that the EGR is not working I expect (but am not 100% sure) that it switches to a back up fuel map based upon no EGR so that the engine is safe and generates a CEL saying that there is a problem. If the ECU does not detect an EGR failure because you have tricked the EGR monitoring circuit it may not map switch leaving you with a lean AFR engine condition which is undesirable.
If you are prepared to rewrite the fuel map to adjust the fuel PW values in the EGR region you can eliminate the lean fuel problem and do the trick to avoid the CEL. [USER=18194]@Honcho[/USER] has remapped his NA1 ECU and I believe is running with the EGR deleted so he can probably give you better advice on the complete solution.
