Big Cam / Misfire tuning question
Thread Starter
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Joined: Nov 2001
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From: Raleigh, NC
Big Cam / Misfire tuning question I have a big cam in my 422 iron block engine.
How do I use LS1-Edit to tune this out?
Not just delete the test... is there a way to tune the PCM to manage the cam better to avoid the misfires?
Thanks!
How do I use LS1-Edit to tune this out?
Not just delete the test... is there a way to tune the PCM to manage the cam better to avoid the misfires?
Thanks!
Thread Starter
Moderator
Joined: Nov 2001
Posts: 3,048
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From: Raleigh, NC
Re: Big Cam / Misfire tuning question I've raised the idle speed and it idles fine.
It's the reproted misfires I'm asking about. I heard there was a way to reduce misfires, or at least REPORTED misfires. But I don't want to just delete the DTC.
The reason I'm asking, I've also heard msifires can unlock the converter or create other performance issues. If this is a myth, someone let me know.
Thanks for your reply, Mekkadon. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
It's the reproted misfires I'm asking about. I heard there was a way to reduce misfires, or at least REPORTED misfires. But I don't want to just delete the DTC.
The reason I'm asking, I've also heard msifires can unlock the converter or create other performance issues. If this is a myth, someone let me know.
Thanks for your reply, Mekkadon. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Thread Starter
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Joined: Nov 2001
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From: Raleigh, NC
Re: Big Cam / Misfire tuning question Well... someone else also old me I should raise the idle some more. I'm not having problems with it dying on me. But, he said it can create TCC issues if it's throwing P0300 codes.
Thanks for the advice. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Thanks for the advice. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Re: Big Cam / Misfire tuning question My idle speed was stock when I put a 218/222 .562/.562 cam in it. It idled fine (Choppy) when warmed up, but tripped misfire codes. Now my idle is set @ 900 in park and 850 in Drive. Do the codes trip while you are driving, or just when your car is idling?
Thread Starter
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Joined: Nov 2001
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From: Raleigh, NC
Re: Big Cam / Misfire tuning question After warm-up and I get out the garage, and clearing the DTC, I don't notice getting the code anymore.
I'll check for sure next time... and go ahead and raise idle.
Thanks. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I'll check for sure next time... and go ahead and raise idle.
Thanks. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Re: Big Cam / Misfire tuning question No problem man, you have a badass TranAm.
<img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" /> <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" /> <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />
<small>[ February 21, 2003, 08:27 PM: Message edited by: Mekkadon ]</small>
<img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" /> <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" /> <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />
<small>[ February 21, 2003, 08:27 PM: Message edited by: Mekkadon ]</small>
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Re: Big Cam / Misfire tuning question dont some set there low misfire/idle tables to like 32000??
i thought that helped get rid of the low rpm misfires, but you still could read them at 50% or WOT??
i set all of my tables in the low rpms to 32000 so i could turn my 300 code back on in case i ever got misfires up top. I just havent prgramed it into my car yet though
i thought that helped get rid of the low rpm misfires, but you still could read them at 50% or WOT??
i set all of my tables in the low rpms to 32000 so i could turn my 300 code back on in case i ever got misfires up top. I just havent prgramed it into my car yet though
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From: Raleigh, NC
Re: Big Cam / Misfire tuning question 98TAauto, I had heard something like that... that you could make misfire detection less sensitve at low rpms, and leave it the same up higher.
This is what I wanted to find out about.
Maybe someone else who has experience doing this will chime in.
Thanks!
This is what I wanted to find out about.
Maybe someone else who has experience doing this will chime in.
Thanks!
Re: Big Cam / Misfire tuning question </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Black LS1 T/A:
<strong> 98TAauto, I had heard something like that... that you could make misfire detection less sensitve at low rpms, and leave it the same up higher.
This is what I wanted to find out about.
Maybe someone else who has experience doing this will chime in.
Thanks! </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The user manual that comes with LS1edit tells how to do it. You can download the manual in PDF format from their site for free.
<strong> 98TAauto, I had heard something like that... that you could make misfire detection less sensitve at low rpms, and leave it the same up higher.
This is what I wanted to find out about.
Maybe someone else who has experience doing this will chime in.
Thanks! </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The user manual that comes with LS1edit tells how to do it. You can download the manual in PDF format from their site for free.
Re: Big Cam / Misfire tuning question the manual is not very helpful in this area!
it does not even cover the TEST PARAMETER section
for the COT in detail.
Just keep this post going maybe C&S performance will chime in, thay have a lot of experience in this field
it does not even cover the TEST PARAMETER section
for the COT in detail.
Just keep this post going maybe C&S performance will chime in, thay have a lot of experience in this field
On The Tree
Joined: Jan 2002
Posts: 110
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From: Suwanee, Georgia
Re: Big Cam / Misfire tuning question You modify the "low" and "idle" misfire detection tables. I take the top three rows, and the first three columns, and set them to 32767. This effectively disables the misfire tests at idle and low rpm's where the cam lope is most severe but leaves the testing in place at mid and high rpms so that legitimate misfires will still be detected and acted upon.
Hope this helps.
Tom
Hope this helps.
Tom
Re: Big Cam / Misfire tuning question </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by spanktu:
<strong> the manual is not very helpful in this area!
it does not even cover the TEST PARAMETER section
for the COT in detail.
Just keep this post going maybe C&S performance will chime in, thay have a lot of experience in this field </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Here it is straight out of the LS1edit manual I downloaded from their site:
7.3.1 Misfire detection
The Maximum Temperature and Minimum Temperature define the temperature range over which the test is run. You could make these both above the normal operating range, so the test isn’t run.
A better solution is to let the test run, but fine tune it so it doesn’t show misfire counts when the engine is running normally. That way if you crack a plug, or have an injector go bad, you will get an error code. When you put a large cam in these engines, the misfire test will falsely identify a misfire. You can loosen up the test at idle, and get rid of these errors. Set the test value in the idle and low RPM tables to 32000, This will loosen up the test, so it should always pass. The test at mid RPM will still be functional.
<strong> the manual is not very helpful in this area!
it does not even cover the TEST PARAMETER section
for the COT in detail.
Just keep this post going maybe C&S performance will chime in, thay have a lot of experience in this field </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Here it is straight out of the LS1edit manual I downloaded from their site:
7.3.1 Misfire detection
The Maximum Temperature and Minimum Temperature define the temperature range over which the test is run. You could make these both above the normal operating range, so the test isn’t run.
A better solution is to let the test run, but fine tune it so it doesn’t show misfire counts when the engine is running normally. That way if you crack a plug, or have an injector go bad, you will get an error code. When you put a large cam in these engines, the misfire test will falsely identify a misfire. You can loosen up the test at idle, and get rid of these errors. Set the test value in the idle and low RPM tables to 32000, This will loosen up the test, so it should always pass. The test at mid RPM will still be functional.
Re: Big Cam / Misfire tuning question that is still not very detailed for the whole
test parameter section.
I know what is in it I have the manual in a 3 ring binder, and that is not enough in detail.
test parameter section.
I know what is in it I have the manual in a 3 ring binder, and that is not enough in detail.
Thread Starter
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Joined: Nov 2001
Posts: 3,048
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From: Raleigh, NC
Re: Big Cam / Misfire tuning question So, according to this, I should set ALL the values in the Low Rpm table to 32000 (or 32767)?
What about the "Idle by Cyl" and "Low RPM by Cyl" tables? Should they be changed?
<small>[ March 04, 2003, 06:00 AM: Message edited by: Black LS1 T/A ]</small>
What about the "Idle by Cyl" and "Low RPM by Cyl" tables? Should they be changed?
<small>[ March 04, 2003, 06:00 AM: Message edited by: Black LS1 T/A ]</small>
