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When I went in to have my ABS fixed the shop told me I had a code for my knock sensor that wasnt illuminating the CEL. My scan tool didnt pick up any code, so I made a graph of my rpm and my degrees of spark advance. Does this graph look weird to anyone?
Worth mentioning - i get a measly 16mpg and my acceleration is way slower than i think it should be. I only use 93, and my engine sure doesnt sound like its knocking.
Is my knock sensor bad? why the weird drops in spark advance? is 43 degrees normal for 2000rpm?
Last edited by Dean Rowell; Oct 9, 2018 at 10:46 AM.
Reason: add photo
Anytime the ECM doesn't see the knock sensor circuit it stops advancing timing and returns to the preset baseline, this is exactly what you're seeing on the graph, intermittent drops in timing.
Usually the culprit is the sub-harness on the sensor.
Err actually ... you wouldn't be able to tell probably because you likely have an intermittent short.
Normally I don't recommend people to use non-oem sensors but get prices from Amazon or something and swap the knock sensor too unless you don't mine tearing into the I take a second time. It's just lost time.
Headed over to z1 motorsports and picked up an oem sensor as well as the sub harness, total $136.
It was a royal pain in the *** but I got it installed, took about 4-5 hours. The car thrusts you into the seat harder than it ever has. My gas mileage will undoubtedly improve as well.
The sub harness was 110% shot. It crumbled apart when I tried to unplug it.
