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jovial_cynic

SR20DET knock sensor problems?

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I think I have an erratic/bad knock sensor.

 

I've noticed that when I advance my timing forward of 15 degrees, I get some pinging, even though I'm running 91 octane. Not great, so then I backed down the timing to something closer to 13 degrees. No more pinging, but also, it seems like my knock sensor is pulling timing so much that I can barely accelerate. 

 

Let's say that my knock sensor is working correctly. Under what circumstances would my engine knock as a result of retarding the timing? Is that even a thing? 

 

Yes, I know I can bypass the sensor. That seems like a dumb idea. But I also don't want to bypass if my sensor is actually detecting something that's happening.

 

Ideas?

Edited by jovial_cynic

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Set timing below 15

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Alrighty!

 

I have a new knock sensor on the way, but bypassing the knock sensor with a 560-kohm resistor and adjusting the timing back to about 13 degrees makes it a little slower, but presumably safe. Still fast. I've noticed that at 15 degrees, it pings a bit, but mostly it pings when just barely off idle. Once the RPMs pick up, the pinging stops. OR, it's possible that it's still pinging like mad and the engine is just too loud to hear it. Even on 91 octane. It's odd. I went ahead and SeaFoam'd the engine to break up carbon deposits, and I'll re-gap the spark plugs to make sure everything is within spec there. It's odd that it pings at 15 degrees, though.

 

In any event, down at 13, no discernible pinging. Vroom vroom.

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Timing is scary on a turbo motor.  You sure it's not a fuel issue?  Lean maybe?   

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Wideband sensor says I'm running rich most of the time. At idle, it's hovering around 12:1 or 13:1, and I never see it go above that. When I push it hard, it gets down to 11:1 to 10:1, etc. Also, I'm running it with the timing retarded enough to cause it to backfire every now and then...

 

It's weird. Very weird.

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Oh, also, Octane 92, not 91. I forgot I'm not in California anymore, and we have better gas up here in Washington.

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hmmm.  I'm curious to hear what you find out.  

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Next thing to test is new spark plugs. I really can't think if any other reason why I'm getting any ping. Gas is good, timing is good, running stock boost while testing, and I've sea-foamed it.

 

Aside from spark plugs or some unnoticed bad spot in the head, I really can't think of anything else. 

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Yeah that's a good idea.  If  someone put the wrong plugs in that could happen.  

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Ooook. New plugs in. 

 

I'm beginning to think I don't have ping. Based on YouTube videos and SR forums, I think I'm either dealing with a rod bearing issue or chain tensioner issue.

 

Looks like the price for bearings is about the same price as the price of the chain tensioner, but as the bearings are a bit more mission critical, I'll go that route first. 

 

Also, my engine roars at 3k rpms. Like, ridiculous. Not sure what's up there. It seems to quiet up a bit once I get higher in rpms, but it's... disconcerting. 

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