LSA seperation and the SES light
Thread Starter
TECH Enthusiast
Joined: Nov 2001
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From: Henderson, NV
LSA seperation and the SES light What is it that actually causes a cam with a lobe seperation lower than 112 to throw the SES. And what harm would it due if any to not get custom programming and let the light switch back and forth from on to off to on.
Launching!
Joined: Dec 2001
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From: Houston, Texas F-Body Heaven!!!
Re: LSA seperation and the SES light A cam with a tighter LSA will have more overlap area (intake and exhaust valves open at the same time). This increased area will do several things. First of all, with the intake and exhaust valves being open at the same time for a longer time, more unburned fuel makes it into the exhaust, possibly setting an SES light (too rich).
The reverse is also possible, with the air/fuel mixture backing up into the intake manifold because of the back pressure in the exhaust, setting a lean code and possible cause some pinging.
The increased overlap will also cause a rougher idle and possibly set a misfire code.
<img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" />
The reverse is also possible, with the air/fuel mixture backing up into the intake manifold because of the back pressure in the exhaust, setting a lean code and possible cause some pinging.
The increased overlap will also cause a rougher idle and possibly set a misfire code.
<img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" />
11 Second Club
Joined: Nov 2001
Posts: 300
Likes: 1
From: Central Florida
Re: LSA seperation and the SES light Most of the time, with a lumpy cam and the stock program in your computer, you're going to throw a "random misfire" code. The computer mistakes the lumpy idle for a misfire and the SES light pops up.
Solution: If you're going to go without programming for any significant amount of time (which I have, I'm on 5+ months and counting) just be careful about how long you let the car idle. Don't let it idle at the same RPM's for more than 30-60 seconds. If you get stuck in traffic, a gentle throttle blip (no more than 1000-1200 RPM's) will prevent the code from popping up. I haven't seen the SES light in months.
Solution: If you're going to go without programming for any significant amount of time (which I have, I'm on 5+ months and counting) just be careful about how long you let the car idle. Don't let it idle at the same RPM's for more than 30-60 seconds. If you get stuck in traffic, a gentle throttle blip (no more than 1000-1200 RPM's) will prevent the code from popping up. I haven't seen the SES light in months.
Thread Starter
TECH Enthusiast
Joined: Nov 2001
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From: Henderson, NV
Re: LSA seperation and the SES light [quote]Originally posted by Carlitos:
<strong>A cam with a tighter LSA will have more overlap area (intake and exhaust valves open at the same time). This increased area will do several things. First of all, with the intake and exhaust valves being open at the same time for a longer time, more unburned fuel makes it into the exhaust, possibly setting an SES light (too rich).
The reverse is also possible, with the air/fuel mixture backing up into the intake manifold because of the back pressure in the exhaust, setting a lean code and possible cause some pinging.
The increased overlap will also cause a rougher idle and possibly set a misfire code.
<img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" /> </strong><hr></blockquote>
does the cam you get determine whether you get a rich or lean mixture? and to avoid this do you get a MAFT or custom programming? I am curious because i dont want to get either of these to act as a sort of "cover up" for the rich/lean mixture causing long term stress without heads or anything. Which would you guys get and what have you guys with a stock motor and cam have?
<strong>A cam with a tighter LSA will have more overlap area (intake and exhaust valves open at the same time). This increased area will do several things. First of all, with the intake and exhaust valves being open at the same time for a longer time, more unburned fuel makes it into the exhaust, possibly setting an SES light (too rich).
The reverse is also possible, with the air/fuel mixture backing up into the intake manifold because of the back pressure in the exhaust, setting a lean code and possible cause some pinging.
The increased overlap will also cause a rougher idle and possibly set a misfire code.
<img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" /> </strong><hr></blockquote>
does the cam you get determine whether you get a rich or lean mixture? and to avoid this do you get a MAFT or custom programming? I am curious because i dont want to get either of these to act as a sort of "cover up" for the rich/lean mixture causing long term stress without heads or anything. Which would you guys get and what have you guys with a stock motor and cam have?
On The Tree
Joined: Jan 2002
Posts: 164
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From: Carrollton, TX
Re: LSA seperation and the SES light YOu guys make a tight LSA sound like a lose-lose for everything.
Tighter LSA will make more mid and just off low end tq than wider one.
Tighter LSA will mean the intake valve will be open further during strongest portion of the induction cycle.
Tighter LSA will make more mid and just off low end tq than wider one.
Tighter LSA will mean the intake valve will be open further during strongest portion of the induction cycle.
Launching!
Joined: Dec 2001
Posts: 231
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From: Houston, Texas F-Body Heaven!!!
Re: LSA seperation and the SES light [quote]Originally posted by HP-GURU:
<strong>YOu guys make a tight LSA sound like a lose-lose for everything.
Tighter LSA will make more mid and just off low end tq than wider one.
Tighter LSA will mean the intake valve will be open further during strongest portion of the induction cycle.</strong><hr></blockquote>
That wasn't the original question, though.
<img src="gr_images/icons/wink.gif" border="0">
'Los
<strong>YOu guys make a tight LSA sound like a lose-lose for everything.
Tighter LSA will make more mid and just off low end tq than wider one.
Tighter LSA will mean the intake valve will be open further during strongest portion of the induction cycle.</strong><hr></blockquote>
That wasn't the original question, though.
<img src="gr_images/icons/wink.gif" border="0">
'Los
Launching!
Joined: Dec 2001
Posts: 231
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From: Houston, Texas F-Body Heaven!!!
Re: LSA seperation and the SES light [quote]Originally posted by R U A LS1:
<strong>
does the cam you get determine whether you get a rich or lean mixture? and to avoid this do you get a MAFT or custom programming? I am curious because i dont want to get either of these to act as a sort of "cover up" for the rich/lean mixture causing long term stress without heads or anything. Which would you guys get and what have you guys with a stock motor and cam have?</strong><hr></blockquote>
It can be anything from the cam specs you chose, to the way those specs were ground (fast vs. slow ramps), to the way it is installed (advanced vs. retarded). The most likely event has already been mentioned...random misfire codes. Get Autotap if you can or have a friend ATap your car when you get an SES light. If it is a misfire code, it is very common and probably not harmful.
'Los
<strong>
does the cam you get determine whether you get a rich or lean mixture? and to avoid this do you get a MAFT or custom programming? I am curious because i dont want to get either of these to act as a sort of "cover up" for the rich/lean mixture causing long term stress without heads or anything. Which would you guys get and what have you guys with a stock motor and cam have?</strong><hr></blockquote>
It can be anything from the cam specs you chose, to the way those specs were ground (fast vs. slow ramps), to the way it is installed (advanced vs. retarded). The most likely event has already been mentioned...random misfire codes. Get Autotap if you can or have a friend ATap your car when you get an SES light. If it is a misfire code, it is very common and probably not harmful.
'Los
