too lean?
Thread Starter
Staging Lane
Joined: Apr 2010
Posts: 73
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From: C.C. TX
too lean? My 98 z28 had an ses light on so i took my car to auto zone so they could run the codes and i got all the o2's sensors but i changed those and it said i was running to lean.
i was just wondering what could cause this?
my mods are a lid, ls6 intake p&p throttle body and maf.
i was just wondering what could cause this?
my mods are a lid, ls6 intake p&p throttle body and maf.
TECH Resident
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Joined: Sep 2007
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From: Holmes County (thats right Amish Country), OHIO
I would say you PP MAF is the problem. Don't touch those things. They are good for 500HP and don't need porting even though it makes it faster because it is leaner. Sure if you lean your motor out to 14:1 it will go .2 faster in a 1/4 but your motor will be shot in no time. Let me explain...
A stock ECU knows how big the MAF is, so air will flow through the sensor at a certain speed and then the engine makes calculations to get the A/F to 13:1. Now when you PP your MAF the air actually moves slower over the wire sensors because it has more room and the ECU doesn't know the MAF is bigger. (Think of it as if you take a river and narrow it it becomes quick and rapid but if you widen it, it slows and flows easily and slower.) So now that the air is moving over the MAF slower the ECU thinks there is less air coming in then what actually is so it reduces fuel to engine leaning it out. So when your ECU is thinking its adding less fuel and making the A/F right its actually leaning it our because the motor is getting more air then what is being seen. Sure a PP MAF makes a car faster in the 1/4 mile but it is a lot harder on the engine with out a tune. Get the ECU tuned to see the bigger MAF or get a stock MAF back in.
A stock ECU knows how big the MAF is, so air will flow through the sensor at a certain speed and then the engine makes calculations to get the A/F to 13:1. Now when you PP your MAF the air actually moves slower over the wire sensors because it has more room and the ECU doesn't know the MAF is bigger. (Think of it as if you take a river and narrow it it becomes quick and rapid but if you widen it, it slows and flows easily and slower.) So now that the air is moving over the MAF slower the ECU thinks there is less air coming in then what actually is so it reduces fuel to engine leaning it out. So when your ECU is thinking its adding less fuel and making the A/F right its actually leaning it our because the motor is getting more air then what is being seen. Sure a PP MAF makes a car faster in the 1/4 mile but it is a lot harder on the engine with out a tune. Get the ECU tuned to see the bigger MAF or get a stock MAF back in.
Thread Starter
Staging Lane
Joined: Apr 2010
Posts: 73
Likes: 0
From: C.C. TX
I would say you PP MAF is the problem. Don't touch those things. They are good for 500HP and don't need porting even though it makes it faster because it is leaner. Sure if you lean your motor out to 14:1 it will go .2 faster in a 1/4 but your motor will be shot in no time. Let me explain...
A stock ECU knows how big the MAF is, so air will flow through the sensor at a certain speed and then the engine makes calculations to get the A/F to 13:1. Now when you PP your MAF the air actually moves slower over the wire sensors because it has more room and the ECU doesn't know the MAF is bigger. (Think of it as if you take a river and narrow it it becomes quick and rapid but if you widen it, it slows and flows easily and slower.) So now that the air is moving over the MAF slower the ECU thinks there is less air coming in then what actually is so it reduces fuel to engine leaning it out. So when your ECU is thinking its adding less fuel and making the A/F right its actually leaning it our because the motor is getting more air then what is being seen. Sure a PP MAF makes a car faster in the 1/4 mile but it is a lot harder on the engine with out a tune. Get the ECU tuned to see the bigger MAF or get a stock MAF back in.
A stock ECU knows how big the MAF is, so air will flow through the sensor at a certain speed and then the engine makes calculations to get the A/F to 13:1. Now when you PP your MAF the air actually moves slower over the wire sensors because it has more room and the ECU doesn't know the MAF is bigger. (Think of it as if you take a river and narrow it it becomes quick and rapid but if you widen it, it slows and flows easily and slower.) So now that the air is moving over the MAF slower the ECU thinks there is less air coming in then what actually is so it reduces fuel to engine leaning it out. So when your ECU is thinking its adding less fuel and making the A/F right its actually leaning it our because the motor is getting more air then what is being seen. Sure a PP MAF makes a car faster in the 1/4 mile but it is a lot harder on the engine with out a tune. Get the ECU tuned to see the bigger MAF or get a stock MAF back in.
yeah i got it in like a package deal so i just said what the heck but i didnt look into it. (now i know that was a mistake) but if i get a tune do you think that will fix it?
TECH Resident
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Joined: Sep 2007
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From: Holmes County (thats right Amish Country), OHIO
Ya you need to talk to a guy who actually tunes whether he can do it with out a dyno tune or reflash the MAF. Call some of your local shops to see what they say they can do. Shops that have been around a while will have many tunes saved with mods just like your that they can do for you with out a full dyno tune for now.
Thread Starter
Staging Lane
Joined: Apr 2010
Posts: 73
Likes: 0
From: C.C. TX
Ya you need to talk to a guy who actually tunes whether he can do it with out a dyno tune or reflash the MAF. Call some of your local shops to see what they say they can do. Shops that have been around a while will have many tunes saved with mods just like your that they can do for you with out a full dyno tune for now.
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Staging Lane
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From: C.C. TX
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iTrader: (3)
Joined: Sep 2007
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From: Holmes County (thats right Amish Country), OHIO
Its up to you really. With a full tune they can tune it for 93 octane reduce the torque management at low RPMs and smooth everything out. Also with a full tune you have piece of mind that your car is running right. I have a friend who did it on his intake only GTO and he gained a little in the quarter mile, so there is some power benefit from a tune, if you have a good tuner.
