Knock Sensor readings - What is a normal ? V6 3.8L

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JohnDee68
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Knock Sensor readings - What is a normal ? V6 3.8L

Post by JohnDee68 »

Hi,
Relating to a 3.8L V6 VX 2002 Commodore engine, factory standards.

I am trying to diagnose a fuel economy issue for some time now and am wanting to understand knock sensor retard readings better.
Please kindly correct me if i am wrong or misunderstand any of this.
I understand knock is from incorrect detonation, which can be from things such as Air/fuel mix and or spark timing or failures.

Only having the one car to work on, I don't know what a standard reading using either software, should actually display when Knock retard is working correctly or not.

I use both software being TunerProv5 RT (xdl log file format) and the Envyous Advanced Engine Diagnostics ( EAL log file format). It seems the Envyous software only reports the knock retard, so I am not even sure of its accuracy in what it shows.eg; knock retard can show anywhere from 10 to 90 degrees retard on the graph. Where Tunerpro seems to not show knock issues?

Would anyone have a log file for either software for a Vx V6 3.8L if possible, which I could look at to compare with mine so I can see if I am experiencing anything out of the normal, please?

Kind regards
John.
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by Charlescrown »

The knock retard value is set in the program and no way it's 90 deg. I think it's around 12 degrees. I think there is a knock count value that must be reached before the retard comes into play. I do know from experience the O2 sensors get lazy on these engines and it can take a very long time before it logs a code. I'd be looking at the cross count activity before starting to think it's knock retard. Good luck and I hope you get a comparison log and do find something.
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by immortality »

In tunerpro you have to make sure you are displaying knock retard in your data. In an ideal world there would be no knock. If there is a lot of knock than it would indicate there is an issue like a sick injector .
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by JohnDee68 »

Charlescrown wrote:The knock retard value is set in the program and no way it's 90 deg. I think it's around 12 degrees. I think there is a knock count value that must be reached before the retard comes into play. I do know from experience the O2 sensors get lazy on these engines and it can take a very long time before it logs a code. I'd be looking at the cross count activity before starting to think it's knock retard. Good luck and I hope you get a comparison log and do find something.
Thanks Charlescrown, yes in TunerPro it seems to be set to 15 degrees for retard value. Presumably that is what the motor should retard the spark timing if a knock is detected?

I can't see in TunerPro a equivalent "Knock Retard" listed, as there is in the AED software. Maybe it is not relevant or the AED software might be incorrect?

Thanks for your feedback.
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by JohnDee68 »

immortality wrote:In tunerpro you have to make sure you are displaying knock retard in your data. In an ideal world there would be no knock. If there is a lot of knock than it would indicate there is an issue like a sick injector .
Thanks for the feedback immortality, I cant seem to find the same in tunerPro as far as "Knock retard" to allow me to show the same as on the AED software. Are you able to explain how in case I am doing something wrong ?

regards
John.
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by immortality »

What XDF file are you using with tunerpro?
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by delcowizzid »

The adx for vx has knock retard for all 6 cylinders you can select them in monitor mode from the drop down or you will have to edit the dashboard to display them
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JohnDee68
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by JohnDee68 »

immortality wrote:What XDF file are you using with tunerpro?
As far as i am aware, I am using the VX_V6_$BD_Enhanced_v0.9e.xdf which I have overtime modified, well what ever file it is that allows me to make my own dash displays (maybe not the XDF).
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by JohnDee68 »

delcowizzid wrote:The adx for vx has knock retard for all 6 cylinders you can select them in monitor mode from the drop down or you will have to edit the dashboard to display them
Ok, I see that.
Though I can't understand how can it do that for each cylinder on a Vx when there is only one knock sensor on each side of the engine?

I do question then how the Envyous software can also display knock for 6 cylinders and wonder where it gets the "knock retard" value from? Maybe it is a total of the knocks from the engine? It does make it hard to diagnose anything when we cant trust the readings it is saying it is and for.

Would a mild restricted exhaust cause knock in an engine?

thanks appreciate all the feedback.
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Re: Knock Sensor readings - What is a normal ? V6 3.8L

Post by vs ss »

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