P0171 Running Lean Driving Me Nuts! Need some help...
#1
P0171 Running Lean Driving Me Nuts! Need some help...
Hey guys I been trying to track this problem down for about a month with no success! My car has been throwing a P0171 code at idle for the past few months. I have tried several things to fix it, but nothing has worked! I'm literally losing my mind and trying to get anyone else's input in what else to check.
The car has no power loss and responds really well.
The car idles between 650+-50 pretty constantly, however, it runs a little rough when the ECU tries to reset the short-term fuel trim levels. I also have extremely terrible gas mileage; I'm talking between 10-12 MPG. At idle the fuel trim is at 135% for both bank one and two.
I have done the following with no success:
Installed Z1 Motorsports silicone hoses all connections are snug.
Put some SeaFoam in hoping to spot some leaks I missed. Didn't notice any.
Replaced Y-Pipe, mid-pipe, and had the mid-pipe welded to the muffler.
Bought a brand new OEM MAF no change.
Swapped both front A/F sensors with used OEM sensors same result.
I even took off my plenum spacer to see if that was a problem nothing changed.
I went around the intake tube and intake manifold with unlit propane no change at idle.
Power balance test engine responded to every fuel injector test.
Hooked up my vacuum gauge to the intake manifold. It reads ~22hg, drops down to ~19hg (When ECU tries to reset A/F trims to 100%), and then raises back to ~22hg when the trim returns to 135%.
Currently building a DIY smoke machine to see if I can find any vacuum or intake leaks. I haven't tested fuel pressure or anything like that though.
Anyone have any other ideas? I'm trying to think outside the box...
Here are some screenshots from Consult 3:
IDLE graph: http://s50.photobucket.com/user/coff...DLE-1.jpg.html
IDLE: http://s50.photobucket.com/user/coff...dia/1.jpg.html
When Idle drops: http://s50.photobucket.com/user/coff...dia/2.jpg.html
Revving at 3K for 5 mins:
http://s50.photobucket.com/user/coff...FTER2.jpg.html
http://s50.photobucket.com/user/coff...FTER1.jpg.html
FreezeFrame: http://s50.photobucket.com/user/coff...P0171.jpg.html
The car has no power loss and responds really well.
The car idles between 650+-50 pretty constantly, however, it runs a little rough when the ECU tries to reset the short-term fuel trim levels. I also have extremely terrible gas mileage; I'm talking between 10-12 MPG. At idle the fuel trim is at 135% for both bank one and two.
I have done the following with no success:
Installed Z1 Motorsports silicone hoses all connections are snug.
Put some SeaFoam in hoping to spot some leaks I missed. Didn't notice any.
Replaced Y-Pipe, mid-pipe, and had the mid-pipe welded to the muffler.
Bought a brand new OEM MAF no change.
Swapped both front A/F sensors with used OEM sensors same result.
I even took off my plenum spacer to see if that was a problem nothing changed.
I went around the intake tube and intake manifold with unlit propane no change at idle.
Power balance test engine responded to every fuel injector test.
Hooked up my vacuum gauge to the intake manifold. It reads ~22hg, drops down to ~19hg (When ECU tries to reset A/F trims to 100%), and then raises back to ~22hg when the trim returns to 135%.
Currently building a DIY smoke machine to see if I can find any vacuum or intake leaks. I haven't tested fuel pressure or anything like that though.
Anyone have any other ideas? I'm trying to think outside the box...
Here are some screenshots from Consult 3:
IDLE graph: http://s50.photobucket.com/user/coff...DLE-1.jpg.html
IDLE: http://s50.photobucket.com/user/coff...dia/1.jpg.html
When Idle drops: http://s50.photobucket.com/user/coff...dia/2.jpg.html
Revving at 3K for 5 mins:
http://s50.photobucket.com/user/coff...FTER2.jpg.html
http://s50.photobucket.com/user/coff...FTER1.jpg.html
FreezeFrame: http://s50.photobucket.com/user/coff...P0171.jpg.html
#2
Think I figured it out
Well, I made a DIY smoke machine for about 30 bucks. If anyone is interest or wants me to post up how I did it let me know.
My brake booster is causing a vacuum leak messing up my A/F ratio. I attached my vacuum gauge next to the pipe it connects to and got better readings. Hooking the booster back up would cause the readings to max out. I recently purchased the AAA extended warranty, so hopefully I can get this covered.
I highly recommend buying a vacuum gauge if you don't have one! It's 15 bucks at Harbor Freight. I could have saved myself $375.00 in parts I didn't need, since it showed all the same symptoms that are used to replace MAF sensors.
Now does anyone need a brand new MAF or four used O2 sensors from an 06 Coupe?? LOL.
My brake booster is causing a vacuum leak messing up my A/F ratio. I attached my vacuum gauge next to the pipe it connects to and got better readings. Hooking the booster back up would cause the readings to max out. I recently purchased the AAA extended warranty, so hopefully I can get this covered.
I highly recommend buying a vacuum gauge if you don't have one! It's 15 bucks at Harbor Freight. I could have saved myself $375.00 in parts I didn't need, since it showed all the same symptoms that are used to replace MAF sensors.
Now does anyone need a brand new MAF or four used O2 sensors from an 06 Coupe?? LOL.
Last edited by coffeysm; 01-24-2014 at 01:25 AM.
#3
Super Moderator
iTrader: (3)
Well, I made a DIY smoke machine for about 30 bucks. If anyone is interest or wants me to post up how I did it let me know.
The problem is either my brake booster or that hard brake booster line! I hooked my vacuum gauge directly to the booster port on the manifold. It steadied out and the alpha settings were more reasonable.
I highly recommend buying a vacuum gauge if you don't have one! It's 15 bucks at Harbor Freight. I could have saved myself $375.00 in parts I didn't need, since it showed all the same symptoms that are used to replace MAF sensors.
Now does anyone need a brand new MAF or four used O2 sensors from an 06 Coupe?? LOL.
The problem is either my brake booster or that hard brake booster line! I hooked my vacuum gauge directly to the booster port on the manifold. It steadied out and the alpha settings were more reasonable.
I highly recommend buying a vacuum gauge if you don't have one! It's 15 bucks at Harbor Freight. I could have saved myself $375.00 in parts I didn't need, since it showed all the same symptoms that are used to replace MAF sensors.
Now does anyone need a brand new MAF or four used O2 sensors from an 06 Coupe?? LOL.
#5
Well, I made a DIY smoke machine for about 30 bucks. If anyone is interest or wants me to post up how I did it let me know.
My brake booster is causing a vacuum leak messing up my A/F ratio. I attached my vacuum gauge next to the pipe it connects to and got better readings. Hooking the booster back up would cause the readings to max out. I recently purchased the AAA extended warranty, so hopefully I can get this covered.
I highly recommend buying a vacuum gauge if you don't have one! It's 15 bucks at Harbor Freight. I could have saved myself $375.00 in parts I didn't need, since it showed all the same symptoms that are used to replace MAF sensors.
Now does anyone need a brand new MAF or four used O2 sensors from an 06 Coupe?? LOL.
My brake booster is causing a vacuum leak messing up my A/F ratio. I attached my vacuum gauge next to the pipe it connects to and got better readings. Hooking the booster back up would cause the readings to max out. I recently purchased the AAA extended warranty, so hopefully I can get this covered.
I highly recommend buying a vacuum gauge if you don't have one! It's 15 bucks at Harbor Freight. I could have saved myself $375.00 in parts I didn't need, since it showed all the same symptoms that are used to replace MAF sensors.
Now does anyone need a brand new MAF or four used O2 sensors from an 06 Coupe?? LOL.
#6
#7
Where did you get the o-ring?
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#8
I bought it at Nissan. Do you still have problems starting? I'd start with the basics: air, fuel, and spark. Check for vacuum leaks and power balance test.
It could be your maf too try cleaning it. If you need a new Mac I have a brand new OEM I can sell cheaper then the dealer.
It could be your maf too try cleaning it. If you need a new Mac I have a brand new OEM I can sell cheaper then the dealer.
Last edited by coffeysm; 05-27-2015 at 06:16 PM.
#9
I bought it at Nissan. Do you still have problems starting? I'd start with the basics: air, fuel, and spark. Check for vacuum leaks and power balance test.
It could be your maf too try cleaning it. If you need a new Mac I have a brand new OEM I can sell cheaper then the dealer.
It could be your maf too try cleaning it. If you need a new Mac I have a brand new OEM I can sell cheaper then the dealer.
Going through the service manual to try and get some ideas.
Cleaning the maf is next on the list.
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