P0171 Fuel Trim System Lean -PCM
#26
Originally Posted by Permafried-
Holy hell if you're having this many problems with your fuel running lean from a cone I'd hate to see what would happen to us considering the bolt-on S/C for the 2.2L.
If all this were just because you put on a new filter and the ECM doesn't like that it's flowing just a touch more than stock, then people would be setting codes left right and center when their stock filters got dirty and airflow dropped a bit. Obviously that doesn't happen. The ECM can very easily cope with slightly more or less air IF there's no problem. So clearly there's a problem here.
I'd be willing to bet that if you pull the airbox assy all apart, put it back together very carefully, paying great attention to making sure it's all sealed up fine, and then pull the battery for 10 secs, you will not see this again. But hell, what do I know...
#27
Proud Playstation 3 Owner
I was running lean there too for the longest time. My air intake tube came all the off on me (note: I have not installed any kind of new filter or anything to it), so check and see if all your stuff is tight. BTW I dont know if this contributied to it or not but I had a bad Cam Sensor, which I dont know how that happened.
#28
Moderator Alumni
Originally Posted by DanM
CHECK FOR VAC LEAKS!!!! The ECM does not set that code because it's getting "more air than it used to". It set that code because it's getting more air than it practically should be able to. There's a big difference. If you just unplug the battery, this will go away for a day or two, then come right back. If you pegged the fuel trims once, and you don't correct the condition, you will just peg them again. The computer is not "confused", in fact it knows EXACTLY what's normal, and it's setting the code because it's not seeing what it should. You need to correct the source of the problem.
There's no great mystery here. I think most ppl don't really understand how the ECM works.... there's nothing abnormal. It's not confused, it's not upset because it's used to seeing one filter and now there's another, and it doesnt just need to be reset. It's telling you that there's a problem you need to fix. That;s what it's designed to do. Find the abnormality (vac leak is more than probable, given that you had your intake plumbing apart), correct it, pull battery to clear the code, and you're done.
BluebaltSS, you said you drilled a hole somewhere? Where? Not in the intake tube anywhere downstream of the MAF, I hope? Because if you did, that's your vac leak right there.
There's no great mystery here. I think most ppl don't really understand how the ECM works.... there's nothing abnormal. It's not confused, it's not upset because it's used to seeing one filter and now there's another, and it doesnt just need to be reset. It's telling you that there's a problem you need to fix. That;s what it's designed to do. Find the abnormality (vac leak is more than probable, given that you had your intake plumbing apart), correct it, pull battery to clear the code, and you're done.
BluebaltSS, you said you drilled a hole somewhere? Where? Not in the intake tube anywhere downstream of the MAF, I hope? Because if you did, that's your vac leak right there.
I dunno if you have access to the manual but short term trim levels being more than 10% off the long term levels will cause this code.
#29
Originally Posted by zinner
DanM you are correct a vacuum leak could cause that code, but given the current situation of replacing the air filter with a high flow version I think it's reasonable to attribute this code to the fuel trim levels.
I dunno if you have access to the manual but short term trim levels being more than 10% off the long term levels will cause this code.
I dunno if you have access to the manual but short term trim levels being more than 10% off the long term levels will cause this code.
I hear what you're saying, but if all this guy did was replace the paper filter with some other brand, and locked it back inside the stock airbox, theres no way the airflow is that much different. ESPECIALLY when he's only had the car for a week, and the LTFTs probably aren't even in equilibrium yet! Not even Ractive filters are that special. I still say small vac leak.
All other discussion aside.... why WOULDN'T you take the 10 minutes to take the tubes off, and put them back on just to be safe? You'd rather drive around with (possibly) a vac leak and leaner than normal condition just because you're too lazy to check?? Just take the tubes off, put em back together carefully, and clear the code. It takes 20 minutes man.
#30
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Originally Posted by DanM
EXACTLY! This is exactly why I'm saying that something is wrong, a leak or something.
If all this were just because you put on a new filter and the ECM doesn't like that it's flowing just a touch more than stock, then people would be setting codes left right and center when their stock filters got dirty and airflow dropped a bit. Obviously that doesn't happen. The ECM can very easily cope with slightly more or less air IF there's no problem. So clearly there's a problem here.
I'd be willing to bet that if you pull the airbox assy all apart, put it back together very carefully, paying great attention to making sure it's all sealed up fine, and then pull the battery for 10 secs, you will not see this again. But hell, what do I know...
If all this were just because you put on a new filter and the ECM doesn't like that it's flowing just a touch more than stock, then people would be setting codes left right and center when their stock filters got dirty and airflow dropped a bit. Obviously that doesn't happen. The ECM can very easily cope with slightly more or less air IF there's no problem. So clearly there's a problem here.
I'd be willing to bet that if you pull the airbox assy all apart, put it back together very carefully, paying great attention to making sure it's all sealed up fine, and then pull the battery for 10 secs, you will not see this again. But hell, what do I know...
#31
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Originally Posted by DanM
I hear what you're saying, but if all this guy did was replace the paper filter with some other brand, and locked it back inside the stock airbox, theres no way the airflow is that much different. ESPECIALLY when he's only had the car for a week, and the LTFTs probably aren't even in equilibrium yet! Not even Ractive filters are that special. I still say small vac leak.
So the airflow is a LOT different, you do read that we datalogged both and found a lot of difference not to mention S/C pressure is up .5 lbs and spools(funny to say, I know it doesnt spool but with the bypass it does in a way) WAAAAY faster, you can flash full bosst I'd say a great deal faster than stock...not trying to be smart just clarifying
oh and trust me we checked the reinstallation well
#32
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OK, I'll take the hose off the TB and take off the other end too and recheck everything. I have already checked the connection for the MAF and made sure everything was tight down below. So say if this doesn't fix my problem. Does that means it's my Fuel Trim? Do I have to get the dealer to fix that or unhook the battery? And if the dealer does it will they void the warranty cuz of the filter?
Thanks alot for all the help!
Dave
Thanks alot for all the help!
Dave
#34
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I got the dealer checking mine too...I disconnected the battery and the code came back on. I got them too check for vacuum leaks, MAF and fuel trim levels...What is going too happen when we order our CAI like K&N Typoon and AEM...How do we fix this problem? Colin
#35
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Okee dokee.
I am just gonna interject with a little bit of sanity here.
Recheck all of your air intake connections, make sure the the clamps are secure and the pipings is seated properly.
There are lots of things that can cause a P0171 it may just be coincidence that it occured so close to the installation of the filter..
Make sure all of the pleats of the filter are even spaced, an irregurlarly shaped filter will disrupt airflow and cause false DTC's.
Make sure your ENGINE OIL DIPSTICK is fully seated in the tube and its seals are okay.
Make sure your ENGINE OIL CAP is properly installed and seal is ok.
Make sure all of the vacuum & emissions hoses are in good condition and properly secure at their connections
Chnage your fuel station, small amounts of water in your gasoline will cause this code
High levels of alcohol contamination in your fuel will cause this code(or mistaken use of E10, E15, or E85 fuel)
A clogged or mechanically failing injector will cause this code.
This condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel, a plugged fuel filter, or a restricted fuel pipe.
Loose or leaking exhaust sytem pieces can cause this code.
Leaking intake manifold gaskets.
Leaking supercharger gaskets or supercharger housing.
The best course of action is to take the car to a competent mechanic skilled in the operation, diagnosis and repair of this vehicle and its engine and emissions control management systems.
I am just gonna interject with a little bit of sanity here.
Recheck all of your air intake connections, make sure the the clamps are secure and the pipings is seated properly.
There are lots of things that can cause a P0171 it may just be coincidence that it occured so close to the installation of the filter..
Make sure all of the pleats of the filter are even spaced, an irregurlarly shaped filter will disrupt airflow and cause false DTC's.
Make sure your ENGINE OIL DIPSTICK is fully seated in the tube and its seals are okay.
Make sure your ENGINE OIL CAP is properly installed and seal is ok.
Make sure all of the vacuum & emissions hoses are in good condition and properly secure at their connections
Chnage your fuel station, small amounts of water in your gasoline will cause this code
High levels of alcohol contamination in your fuel will cause this code(or mistaken use of E10, E15, or E85 fuel)
A clogged or mechanically failing injector will cause this code.
This condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel, a plugged fuel filter, or a restricted fuel pipe.
Loose or leaking exhaust sytem pieces can cause this code.
Leaking intake manifold gaskets.
Leaking supercharger gaskets or supercharger housing.
The best course of action is to take the car to a competent mechanic skilled in the operation, diagnosis and repair of this vehicle and its engine and emissions control management systems.
#36
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Ok guys well I just got back from the GM dealership they diagnostic the car most of the day and found out it was a bad O2 sensor....Even with the stock filter it was throwing that lean code. So they ordered a new O2 it will be in on Tuesday...Hope this helps guys.....Colin
#37
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Hey guys, I checked the stuff you told me to and it all looks ok. I'll take it back to the dealer and see what happens. Should I put the stock filter back in or will they even notice?
#38
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Originally Posted by BluebaltSS
Hey guys, I checked the stuff you told me to and it all looks ok. I'll take it back to the dealer and see what happens. Should I put the stock filter back in or will they even notice?
#39
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OK, I put my old filter back in and since then my CEL hasn't come on since. It might in a bit of time, not too sure. Got an apointment at the dealer tommorow so we will see whats going on with this. I'll keep ya posted.
#40
MAF sensor and K+N filter oil do not go together......the oil will contaminate the MAF wire causing it to read incorrectly.....this is very commong on all MAF cars using a K+N filter...............easy fix as all you have to do is clean the MAF wire using a Q-tip and alchohol
#41
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you should NOT ever use soapy water to test a leak in a vac system as it will get sucked in to the vac system use carb cleaner and if it leaks it will change the rpms never anything you cant put in your engine never ever ever
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