Got a 91 Z28 with a L98. SLP runners, SLP headers, cat back flowmaster. I keep getting a code 43 when engine is hot, 180 + deg. usually when its 90 deg or higher outside. The Service Engine Soon (SES) light comes on for couple minutes, then goes off, comes back on, sometimes less than a minute, then goes off. I know on an OBD II system, the code will stay on till a certain amount of key cycles depepnding on code. Is OBD I supposed to act the same, in other words, do I have an intermittent problem? or does the SES light come on only when the fault is present?
The knock sensor isn't even in the block, it's secured in insulation, and still wired up, with the ground going to the battery. When driving I lose all spark advance, and timing retards, sometimes up to 20 deg. depending on how hard I step on it. Are there any other things that would cause a code 43 besides the knock sensor, knock sensor wires, or prom chip? The engine doesn't ping. Would header flow have any effect on internal noise in engine? Just doesn't make sense since knock sensor isn't even in block ?????????????????????????????????????????????????????????????? I have 5 volts to wire, and 2.50 backprobing terminal.
Any advice is taken into consideration