Timing and knock retard degrees questions

[Deleted member 33561]

My car feels sluggish and I noticed the Knock retard hitting -4 to 5 degrees when accelerating from 45 to 60mph in 4th gear. Is that normal? I also noticed the Spark advance drops down to about 15 degrees at that time. Is that normal too? (I'm no mechanic)
Any help/suggestions appreciated.,

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[jenksdrummer]

Try different gas when you get a chance.

From one of these sources, as they'll like y be more consistent/quality.

https://en.wikipedia.org/wiki/Top_Tier_Detergent_Gasoline

 

[Deleted member 33561]

My car has never had anything in it but Shell 93 Octane if I can believe what the pump says.

 

[jenksdrummer]

My car has never had anything in it but Shell 93 Octane if I can believe what the pump says.

So much for that thought. =/

I'm out of knowledge...lol

 

[Deleted member 33561]

That's all I had too. I wonder if someone here knows where the "Knock sensor" is located if that could be a problem?

 

[Dr. Norts]

My car feels sluggish and I noticed the Knock retard hitting -4 to 5 degrees when accelerating from 45 to 60mph in 4th gear. Is that normal? I also noticed the Spark advance drops down to about 15 degrees at that time. Is that normal too? (I'm no mechanic)
Any help/suggestions appreciated.,

Are you seeing negative values or positive values. The knock values are kind of backwards to what you would think. Are you seeing -4 to -5 or -4 to +5???

Negative numbers are adding timing which is good and positive numbers are subtracting timing.

 

[Deleted member 33561]

I'm not a mechanic as I've said often but what you are saying seems backwards to me. Since I'm getting negative numbers at the same time the "timing" is going from 21 deg BTC to 15/16 deg BTC. I'm reading the numbers on a Lund "Ngauge". The two timing numbers I see are "Deg BTC and Cylinder # 1 deg BTC which are reading essentially the same thing. When I let off the throttle both reading go up to something like 40 degrees. I seem to remember when cruising at a steady speed the KnockRet goes to zero. Just a slight increase in throttle will cause Knockret to go to -1.5 to - 2.0 deg. By the way these numbers are with the car bone stock. When I had the JLT CAI and the Lund tune in the car the Knock retard numbers were higher meaning up to - 8 degrees.

 

[Rhinogt]

Negative knock = good. What rpm/load/throttle position are you looking at when you see it go from 21-15 degrees?

 

[Deleted member 33561]

Knock retard is essentially what it says as far as I know. It is only a "retard" of the timing when a knock is detected. I''m sure the sensor does not "add" timing because it always goes backs to zero when at a steady speed or foot off the gas.

 

[Deleted member 33561]

Negative knock = good. What rpm/load/throttle position are you looking at when you see it go from 21-15 degrees?

My memory is not good at my age but I just put the car in 4th gear and mashed the pedal (not all of a sudden but fairly quick). I was trying to watch the gauge for all 3 values while accelerating at a pretty fast rate. I tried to video it but was not able to do so.

 

[Ace21]

I'm not a mechanic as I've said often but what you are saying seems backwards to me. Since I'm getting negative numbers at the same time the "timing" is going from 21 deg BTC to 15/16 deg BTC. I'm reading the numbers on a Lund "Ngauge". The two timing numbers I see are "Deg BTC and Cylinder # 1 deg BTC which are reading essentially the same thing. When I let off the throttle both reading go up to something like 40 degrees. I seem to remember when cruising at a steady speed the KnockRet goes to zero. Just a slight increase in throttle will cause Knockret to go to -1.5 to - 2.0 deg. By the way these numbers are with the car bone stock. When I had the JLT CAI and the Lund tune in the car the Knock retard numbers were higher meaning up to - 8 degrees.

All of that is normal, timing will drop to correlate with the timing maps at a given RPM and load. Coming from tuning JDM ECUs to these I have yet to understand why Ford and others are make their "Knock retard" seem confusing.

So just for future reference -# knock retard means that timing is being added in over the base timing maps which is good, 0 means that there is no condition for extra performance or that the engine is operating in lean cruise, and +# knock retard means that the ECU is actively pulling timing which is not good.

 

[Deleted member 33561]

Thanks for the info. My only other experience was with my Scatpack and using the Diablo tuner I never saw more than 0.5 or 1.0 degrees of short term knock retard.
Also I'm still confused about the fact that there is a positive value since the Lund Ngauge never goes positive that I've seen. It goes from zero to -8 degrees of retard. My Scatpack never went above 0.5 or 1.0 degrees of short term knock retard and no long term knock retard. (Again my memory is bad or that's my excuse and I'm sticking to it)
So I guess my car is OK after all.
Thanks again.

 

[Deleted member 33561]

I can't stop thinking about this. How do you reconcile the timing droping from 21 deg to 15 degrees as the retard value is going from 0 to -5 degrees. Doesn't changing the timing from 21 deg before TDC to 15 Deg before TDC mean you are losing power because I always thought more deg BTC means more power unless your engine starts to knock. Then you reduce timing until it stops knocking.
And why would I want timing to decrease when I press on the gas. All seems contradictory to me.
Are you sure the Lund Ngauge reads the way you are saying?
(Sorry I just can't get it right in my head)

 

[Ace21]

So the biggest thing with the timing is that it is dropping when you are applying more throttle, meaning that calculated load will change and so will timing. If you are super concerned about it then take a short log and through it up so we can see it.

 

[Dr. Norts]

Knock retard is essentially what it says as far as I know. It is only a "retard" of the timing when a knock is detected. I''m sure the sensor does not "add" timing because it always goes backs to zero when at a steady speed or foot off the gas.

Your understanding is right on the retard part but wrong on the assumption it doesn't advance timing.

The sensor does indeed allow an add (advance) timing. That's what the negative numbers are. When the numbers are negative it's adding timing and when they are positive it'll subtract (retard) timing.

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