ZR-1 Net Registry Forums - View Single Post - Knock Sensor; What happens if its disconnected

XfireZ51 · 06-29-2009

Lee,

Looking at the FSM and reading the Diag Charts and reviewing of Code 43, the ECM only retards timing when it receives an AC signal produced by the KS. There's no indication that the ECM goes into a "default" timing if it doesn't "see" the knock sensor. If there's an open circuit, as in your case, then a voltage of either >3.62v or <1.44v will cause the ECM to set a code 43 after 24 seconds. I don't have an answer as to why you don't have a code set.
There's a second test the ECM will run under the conditions of Coolant at > 93C and High engine load. If the ECM does not see a response from the ECM, a Code 43 will be set. I also remember that the GN guys would pull the knock sensor connector to avoid KR (Knock Retard). Of course, the LT-5 ignition could be different but the GN ignition is close as it uses Waste Spark.

06-29-2009	#5
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,686	Re: Knock Sensor; What happens if its disconnected Lee, Looking at the FSM and reading the Diag Charts and reviewing of Code 43, the ECM only retards timing when it receives an AC signal produced by the KS. There's no indication that the ECM goes into a "default" timing if it doesn't "see" the knock sensor. If there's an open circuit, as in your case, then a voltage of either >3.62v or <1.44v will cause the ECM to set a code 43 after 24 seconds. I don't have an answer as to why you don't have a code set. There's a second test the ECM will run under the conditions of Coolant at > 93C and High engine load. If the ECM does not see a response from the ECM, a Code 43 will be set. I also remember that the GN guys would pull the knock sensor connector to avoid KR (Knock Retard). Of course, the LT-5 ignition could be different but the GN ignition is close as it uses Waste Spark. Last edited by XfireZ51; 06-29-2009 at 11:17 PM.