I'll trace through how I got here as well.
Troubleshot using this flowchart to get to the point where it was determined to be intermittent.
Checked connections at knock sensor, ESC Module and ECM. They looked good. Checked CKT 485 (C to B7) and it was neither open or shorted to ground...
I'm pretty puzzled.
I investigated CKT 453 to ground some more. I still get 50kOhms if I measure from terminal A in the connector to ground.
I checked ECM ground (A12 at ECM to negative end of battery cable) and it was about 1 ohm. This was a relief given how hard that seemed like it would be...
Had to take a break from looking at it but have been back at it for a while. I should have done a better job documenting what was done and what changes were noted. I have started doing that more recently but here is what has been changed with the results as best as I can remember.
Replaced MAP...
Hooked the scanner up today and there are a few knocks detected when I turn the truck on or off. No accumulation at idle or when I drove around the neighborhood.
I still have the problem with it advancing timing too far. (20 initial and 40 total)
I did notice with the scanner plugged in that...
Using this flowchart from the pubs. Now I don't have a scan tool but I am pretty sure there is no knock at idle. I went on to test 2 and verified with a timing light that timing does get retarded a couple of degrees after I tap on the engine block with a wrench. So Cod 43 is intermittent and it...
One symptom to add. Engine documentation said to set timing using the total timing method. When I checked that, I was getting 20 deg adv at idle and 40 at 3500 RPM. Should have been 10-16 at idle and 34-36 at 3500 RPM. This is with static set at 0. No other updates.
I don't have the background to be able to answer this.
Validated that the part number was correct on ACDelco's site.
Torqued to 14 ft-lb.
Checked continuity in the wire between the connection to the knock sensor and the ESC module.
I'm following you. I'll check this again using the timing...
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...