why would knock retard go away over time

[jrb1027]

I have an ongoing issue with the kr on my car, im almost sure it is false, it happens when i stomp the throttle less than 3k rpm its ranges from 10-15 degrees depending on how fast i let off. I have noticed that if i let me car idle for a half hour or so the kr vanishes could there be an error in the pcm?

[BillBoost37]

Let me say this back to make sure I understand what you are saying.

If you take the car out cold and romp it while the rpm are under 3K, you get 10-15 degrees of kr
If you warm the car up first and them romp it, you don't get KR in the same areas under 3K rpm.

You are making a change that isn't the pcm. You are allowing the car to be up to temp. Temp and other things can have an effect on the amount of timing. I would say the issue is in your tune or your foot.

[industrialfish]

Correct me if I'm wrong, but aren't the knock sensors disabled under 160 degrees anyway?

[jrb1027]

You are correct bill except it is at normal running temps when kr happens unless the car has been idling or driveing longer than half hour to 45min

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[jrb1027]

Industrial your correct but its not under 160 when it happens I let it get warm before I romp

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[BillBoost37]

Thank you for clarifying. So the difference is not temp, it's only runtime.

Have you considered that your car wakes up slow?

[jrb1027]

Yes runtime seems to be the key, no I haven't considered that, it doesn't slowly go away its either there or it isn't and when it is there its always 10-15kr

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[jrb1027]

i wish someone had this problem before do you think a video of my gauges could help

[jrb1027]

bump

[nik12937]

Shot in the dark, but have you checked for vacuum leaks, like as soon as it gets into operating temperature? It could be that you have a leak that makes the engine run lean until the engine bay heat soaks and whatever is leaking swells and seals. Not sure if that could cause that much KR though...

[jrb1027]

ill take a look but my map is -21 at idle last time i checked and im not cammed so that should mean there is no vac leak correct?

[Fivefingerdeathpunch]

Fuel trims will tell you if a leak is there.

Though -20 to -21 is good vacuum to have.

[jrb1027]

o2 is in the 920s 930s at wot

[jrb1027]

bump

[Fivefingerdeathpunch]

Narrowband readings are sorta okay, sorta not to follow when trying to figure stuff out.

Those reading would be a guess of mid 11's for AFR, but a wideband is the best way to know.

[jrb1027]

yea i really need to get a wide band, would anyone suggest buying a new o2 sensor for when i retune, ive heard that over time the o2 can change readings.