has anyone ever seen the knock sensors fail without tripping a MIL? I Have noticed that my truck sounds like it is pinging on 87 and hardly ever when run on 93. With a scanner hooked up I never see any KR readings in the data display when I can hear the "pinging"
oh its an 01 with a 5.3 and 150k miles
-Rich
The knock sensors can send false readings to the pcm and the pcm will pull lots of timing, causing a loss in power.
If the kr sensors are bad, they cause funny timing issues and pinging, BUT,
If you're still hearing pinging with 93oct, then it's probably not the ks, because the pcm doesn't add more timing than it's already setup for if the ks are bad.
Probably a lean condition, dirty maf, low fuel pressure, carbon, dirty system, injectors, etc.
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+1
KS problems are common due to rust and corrosion but the common problems make them not sensitive enough and/or set DTC's.
But the Knock Retard value is staying at 0 when I can hear the pinging, so it never pulls any advance out. Which leads me to beleive that the sensors aren't working. shouldn't the pinging be picked up by the knock sensors? And shouldn't the truck be able to run fine on 87?
all i can say is my buddy's 03 4.8 had the 2 kncok sensors go bad and it didnt throw and codes they both were rusted and corroded and his truck pinged and ran like straight cow SH**... now with the new ks its all good
07 sierra 5.3
Remington edition
Afe CAI closed box
SLP Cat-back (stainless)
20in HD hoss black and chrome
78 Chevy longwheelbase,350,holley 600cfm,6inch lift
35'' swampers. 87 bed,fuel tank,doors.
Yeah chad, I bet I've got the same issue. I know the guy used to wash under the hood whenever he would wash the truck, I bet water made its way down to the sensors. I think I'm gonna buy the intake gaskets, both sensors and the harnesses.
-Rich
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