Like the title says I am chasing my tail trying to figure out what is causing this.
Background on the truck. It is 1989 V1500 Suburban. I recently replaced engine with a Blueprint crate engine. While this was being done I had the transmission rebuilt. Exhaust was previously leaking from every joint so had that rebuilt. Couldn't get the manifolds off the old engine so replaced with shorty headers. The only other change was an Edelbrock intake.
Once it was back up and running I was getting codes 32 and 43. No noticeable issues as far as performance other than the SES light. I replaced the EGR valve and 32 went away. 43 persists but only appears if I really stomp on the gas. I can drive around all day in town (55 and below) and nothing pops. Based on what I have read on the internets I think that I am getting the code when the forced knock test fails twice.
I knew I was getting code 32 before the engine change. It had been there since I got the truck a few years ago. I never got code 43 before the engine change but I also wasn't checking codes very often since I expected 32 to pop up just about any time I drove above 45mph.
Since then I have:
-Replaced the Knock Sensor with ACD P/N 231-324. The one that had been installed looked very similar but had a black nub
-Checked static timing. It was 2 deg advanced. Moved back to 0.
-Validated connection between knock sensor and ESC module (P/N 16052401). P/N noted because some threads indicated that folks are getting the wrong (but similar looking) knock sensor form parts stores and that they needed to be paired with the correct ECS module
-Tried to trip code 43 by banging on the engine block near the sensor with a wrench. Tried this with both the engine on and with key on (engine off). Went at it pretty good and never could get the SES light to come on. This reinforces to me that the SES light is for a failed forced knock test.
Questions that I know I have for the crowd:
1. Am I on the right track thinking it is failing the forced knock test?
2. How many Ohms should my knock sensor read? I checked the black nubbed one and it read 99kOhms. I've read that one knock sensor should read about that much and another that reads around 4kOhms. Can't find anything that says which is correct for me, just that I should make sure I have the correct one. For what its worth I saw a youtube video of a guy checking the white nubbed knock sensor and it also read the 100k(ish) kOhms.
3. Is that the correct knock sensor for the ESC module I have? How could I find out?
4. Should I have been able to trigger the SES light by banging on the engine block next to the sensor? If yes I think this leads towards a problem with the sensor or ECS module?
5. If no to item 4 I am leaning towards the temp sensor. Could the single wire O2 sensor also be the gremlin. I am wondering if my exhaust changes are hiding something there.
I don't really like throwing parts at the problem but haven't seen anything that would lead me to be able to troubleshoot this to the culprit. Thanks
Background on the truck. It is 1989 V1500 Suburban. I recently replaced engine with a Blueprint crate engine. While this was being done I had the transmission rebuilt. Exhaust was previously leaking from every joint so had that rebuilt. Couldn't get the manifolds off the old engine so replaced with shorty headers. The only other change was an Edelbrock intake.
Once it was back up and running I was getting codes 32 and 43. No noticeable issues as far as performance other than the SES light. I replaced the EGR valve and 32 went away. 43 persists but only appears if I really stomp on the gas. I can drive around all day in town (55 and below) and nothing pops. Based on what I have read on the internets I think that I am getting the code when the forced knock test fails twice.
I knew I was getting code 32 before the engine change. It had been there since I got the truck a few years ago. I never got code 43 before the engine change but I also wasn't checking codes very often since I expected 32 to pop up just about any time I drove above 45mph.
Since then I have:
-Replaced the Knock Sensor with ACD P/N 231-324. The one that had been installed looked very similar but had a black nub
-Checked static timing. It was 2 deg advanced. Moved back to 0.
-Validated connection between knock sensor and ESC module (P/N 16052401). P/N noted because some threads indicated that folks are getting the wrong (but similar looking) knock sensor form parts stores and that they needed to be paired with the correct ECS module
-Tried to trip code 43 by banging on the engine block near the sensor with a wrench. Tried this with both the engine on and with key on (engine off). Went at it pretty good and never could get the SES light to come on. This reinforces to me that the SES light is for a failed forced knock test.
Questions that I know I have for the crowd:
1. Am I on the right track thinking it is failing the forced knock test?
2. How many Ohms should my knock sensor read? I checked the black nubbed one and it read 99kOhms. I've read that one knock sensor should read about that much and another that reads around 4kOhms. Can't find anything that says which is correct for me, just that I should make sure I have the correct one. For what its worth I saw a youtube video of a guy checking the white nubbed knock sensor and it also read the 100k(ish) kOhms.
3. Is that the correct knock sensor for the ESC module I have? How could I find out?
4. Should I have been able to trigger the SES light by banging on the engine block next to the sensor? If yes I think this leads towards a problem with the sensor or ECS module?
5. If no to item 4 I am leaning towards the temp sensor. Could the single wire O2 sensor also be the gremlin. I am wondering if my exhaust changes are hiding something there.
I don't really like throwing parts at the problem but haven't seen anything that would lead me to be able to troubleshoot this to the culprit. Thanks