First Scan & Timing Retard
Thread Starter
Racer
Joined: Jan 2001
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From: Frederick MD
First Scan & Timing Retard
Just ran Auto tap for the first time, since the HotCam install, and I'm getting like -30 degrees of timing retard. What is normal for timing advance/retard. Here's the log file, should have an .atl extension for Autotap.
http://temp.corvetteforum.net/c4/tdock/8-12.txt
[Modified by tdock, 10:59 AM 8/13/2002]
[Modified by tdock, 11:00 AM 8/13/2002]
http://temp.corvetteforum.net/c4/tdock/8-12.txt
[Modified by tdock, 10:59 AM 8/13/2002]
[Modified by tdock, 11:00 AM 8/13/2002]
Le Mans Master
Joined: Oct 1999
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From: Sachse Texas
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Re: First Scan & Timing Retard (tdock)
I don't have autotap so I can not look at your log file, but you should never see -30 degrees of timing being pulled out from the knock sensors. Maybe 6-8 due to the sensors picking up either false or real knock. It is probably only running 36-40 degrees of timing anyway.
You should see timing advance at WOT above 4000 rpm to be roughly the same and somewhere in the 36-42 range on stock programming. Knock retard should be 0 if all is well. If you feel you are getting false knock, you can try the LT4 knock module in place of your LT1 module. The LT4 module is designed to hide the false knock that may be picked up from the roller rockers.
You should see timing advance at WOT above 4000 rpm to be roughly the same and somewhere in the 36-42 range on stock programming. Knock retard should be 0 if all is well. If you feel you are getting false knock, you can try the LT4 knock module in place of your LT1 module. The LT4 module is designed to hide the false knock that may be picked up from the roller rockers.
Thread Starter
Racer
Joined: Jan 2001
Posts: 425
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From: Frederick MD
Re: First Scan & Timing Retard (Vette92)
OK changed it to a comma delimited file, so it can be imported into Excel.
http://temp.corvetteforum.net/c4/tdock/8-12.txt
If anyone wants to take a peak.
I guess I meant to say timing advance was -38 to -42 at WOT, not retard.
Shouldn't I have a LT4 Knock module in an LT4 already?
http://temp.corvetteforum.net/c4/tdock/8-12.txt
If anyone wants to take a peak.
I guess I meant to say timing advance was -38 to -42 at WOT, not retard.
Shouldn't I have a LT4 Knock module in an LT4 already?
Le Mans Master
Joined: Oct 1999
Posts: 9,713
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From: Sachse Texas
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Re: First Scan & Timing Retard (tdock)
Looks ok to me except for the knock retard degrees is real high in the one real romp you had in the file (timestamp 32128-32121). Not sure how to read it as I show one cell having 225 degrees of knock retard :confused:. The other thing I find interesting is that One O2 sensor seems to be completely dead. Most of the file is podunking around and 30 degrees of timing would be about right to see from the computer.
Yes you would already have the LT4 knock module. For some reason the first time I read this I saw you had an LT1. :crazy:
Maybe someone else will have something to add.
Chris
Yes you would already have the LT4 knock module. For some reason the first time I read this I saw you had an LT1. :crazy:
Maybe someone else will have something to add.
Chris
Thread Starter
Racer
Joined: Jan 2001
Posts: 425
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From: Frederick MD
Re: First Scan & Timing Retard (Vette92)
The dead 02 makes sense, 'cause I could unplug the MAF and the car would run much smoother. Is there any way to tell which O2 it is from the scanner/file, I'm assuming one of the front ones?
Any method for tracking down knock?
Any method for tracking down knock?
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
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Re: First Scan & Timing Retard (tdock)
Try swapping the front O2 sensors for the back ones. See if the results change. It is easy enough to do if you can get a wrench on them.
