Code P1171

[snowtrooper1966]

The Dragon is giving code:
P1171
and my code reader is displaying:
"Unidentified Code"
Thanks in advance for any info...
Best,

[Ldub]

P1171
Fuel System Lean During Acceleration :_wrench:

[Tone]

P1171 Fuel Air Metering / Fuel System Lean During Acceleration
- could be dirty maf, dirty intake air temp sensor, clogged fuel filter and/or clogged EGR. Any symptoms? Search .info for where these are and how to address the issues. And actually a search for P1171 brought up info on this very board from 2004...

BTW, Anything above P1000 will be Manufacturer specific and NOT in a general list of codes. See attached PDF

[Jolly Roger VX'er]

Clear the code and see if it comes back...also see if it happens while going up a hill.

Mine kicked this code whenever you started putting the spurrs to her while going up a hill...after changing things out (fuel filter, intake gaskets, bad injector O-rings, a cracked fuel injector...) it wound up being my MAF sensor. Try cleaning that first.

I never did get a MAF sensor code though..which is why it took me a while to figure out and fix the problem.

[snowtrooper1966]

Thanks, gentelmen!
No symtoms at all.
I changed the fuel filter last summer, as well as trated the fuel system with seafoam.
I am also getting codes:
P0137 02 sensor circuit low voltage (bank 1 Sensor 2)
&
P0157 02 sensor circuit low voltage (bank 2 sensor 2)
I am guessing I need to replace the post cat 02 sensors?

I have cleared the codes, and they come back pretty quick.
I will clean the MAF and see what happens with the P1171 code.
Best,

[Jolly Roger VX'er]

Thanks, gentelmen!
No symtoms at all.
I changed the fuel filter last summer, as well as trated the fuel system with seafoam.
I am also getting codes:
P0137 02 sensor circuit low voltage (bank 1 Sensor 2)
&
P0157 02 sensor circuit low voltage (bank 2 sensor 2)
I am guessing I need to replace the post cat 02 sensors?

I have cleared the codes, and they come back pretty quick.
I will clean the MAF and see what happens with the P1171 code.
Best,

I got one of these oxygen sensor codes too when I had the previously mentioned problem. Autozone wanted to sell me an oxygen sensor but I tried cleaning the MAF first. When that didn't help I opted to replace it (nobody tests them.) That wound up clearing up "both" of my trouble codes of "Lean under acceleration" and "P0157".

[snowtrooper1966]

Oh, and many thanks to Tone for the PDF! Invaluable info for all!

Jolly Roger VX'er, so based on your experience, changing the 02 sensor cleared both codes?

Am I correct in thinking the 2nd sensor in both banks is the post cat?

Best,

[Jolly Roger VX'er]

Oh, and many thanks to Tone for the PDF! Invaluable info for all!

Jolly Roger VX'er, so based on your experience, changing the 02 sensor cleared both codes?

Am I correct in thinking the 2nd sensor in both banks is the post cat?

Best,

no...i never had to fool with the oxygen sensors. I just had to try cleaning the MAF...then when it didn't help...I replaced the MAF.

My MAF turned out to be bad so cleaning didn't help. But, at $150 for a MAF..why not try cleaning it first using some CRC MAF spray for like $4.

It was explained to me that sometimes a "real" problem will spawn some other codes that really are not the problem.

In this case..the "real" problem was the MAF sensor....which spawned a "false" code of P0157 too.

[snowtrooper1966]

Got it!
You replaced the MAF after cleaning did not clear the codes.
That throws a curve in my plans. 150 for a MAF (if cleaning does not do it) or 50 to 100 for 2 oxygen sensors....
What milage where you at when this happened?

[Jolly Roger VX'er]

Got it!
You replaced the MAF after cleaning did not clear the codes.
That throws a curve in my plans. 150 for a MAF (if cleaning does not do it) or 50 to 100 for 2 oxygen sensors....
What milage where you at when this happened?

I'd say to the best of my memory it was around 40,000 miles. I remember getting my Supercharger on at 36,000 miles and it was about a few months later that I started having this problem.

[snowtrooper1966]

Nice!
I Will clean the MAF tomorrow and see what happens...

[Tone]

Uh, if you are getting O2 codes as well then it is probably those and not the MAF. Any OTHER info? The whole story really helps give you a complete diagnosis instead of a bunch of WAGs thrown in by those who have had some of the problems you mention....

[snowtrooper1966]

As far as I can tell, there are no performance issues. Nothing to indicate trouble besides the codes.
IIRC, these codes appeared after I had been driving around with way too much oil in my Dragon, a result of not getting good readings off my dipstick and fear of excessive oil burn.
The thought was I may have fouled the sensors, but it has been some time, and I am still getting the codes....
Best,

[Jolly Roger VX'er]

I'd still clean the MAF first & see if that cures your problem. Easy, cheap & quick to try. If that fails...let us know what you end up doing and how it all turns out!

[deermagnet]

Find what's causing the lean condition and fix it. The sensor voltage will then increase and the codes will go away.
http://www.drivehq.com/file/df.aspx/publish/mgpa/vx/vx/p0137.gif

http://www.drivehq.com/file/df.aspx/publish/mgpa/vx/vx/p1171.gif
Based on the experience of others here, it's very likely you have a dirty MAF sensor. Get some electrical parts cleaner or MAF sensor cleaner at Wal-Mart for a few bucks. I clean mine once a year. If that doesn't work, try something else on the list of fixes.

Mark Griffin

[snowtrooper1966]

Wierd...
I cleared the codes and then got some MAF cleaner. The check engine light usually comes back on in a few miles. It stayed off all day yesterday. I did not get a chance to clean the MAF yet. I will do it today and keep you all posted.
Best,

[crager34]

Cleaning the MAF is super easy and won't cost you much time at all, AND it's worth it simply for preventative maintenance.

[Vendetta]

Forgive my waking this tired 'ol thread, but I'm having the EXACT same codes thrown at the moment.

P1171 - Fuel System Lean During Acceleration
P0157 - O2 Circuit Low Voltage (Bank 2 Sensor 2)
P0137 - O2 Circuit Low Voltage (Bank 1 Sensor 2)

My wrench swears up and down that he already replaced all the O2 sensors with brand new ones. He's at a loss. Therefore I am at a loss.

Snowtrooper, can you put please a ribbon on this one and tell us if and how you solved this set of codes?

Thanks,
-V

[Ldub]

Forgive my waking this tired 'ol thread, but I'm having the EXACT same codes thrown at the moment.

P1171 - Fuel System Lean During Acceleration
P0157 - O2 Circuit Low Voltage (Bank 2 Sensor 2)
P0137 - O2 Circuit Low Voltage (Bank 1 Sensor 2)

My wrench swears up and down that he already replaced all the O2 sensors with brand new ones. He's at a loss. Therefore I am at a loss.

Snowtrooper, can you put please a ribbon on this one and tell us if and how you solved this set of codes?

Thanks,
-V

I'm fairly certain that those codes are indicative of unmetered air getting into the intake system, somewhere downstream of the MAF sensor.
Could be vacuum leak (hose or otherwise)
OR, vacuum leak (intake manifold gaskets)

Look HERE (http://www.vehicross.info/forums/showthread.php?t=13268&highlight=brake+booster+stainless)

[Vendetta]

Thing is, my wrench cleared the codes this morning prior to my 100-mile trek to the yard and back, and they haven't come back on.

Granted, I was driving on eggshells going for maximum MPG (http://vehicross.info/forums/showthread.php?threadid=22196), but still... I would think they'd come on if it were something like a gasket leak. I don't know, so here I am.

-V

[Ldub]

Thing is, my wrench cleared the codes this morning prior to my 100-mile trek to the yard and back, and they haven't come back on.

Granted, I was driving on eggshells going for maximum MPG (http://vehicross.info/forums/showthread.php?threadid=22196), but still... I would think they'd come on if it were something like a gasket leak. I don't know, so here I am.

-V

Yep...

Same experience, as long as I'm a "good boy" with regard to the skinny pedal...nothing.

But when I drive "normally", I would get the same codes. Start with a good maf cleaning...:yesgray:

[Cobrajet]

Thing is, my wrench cleared the codes this morning prior to my 100-mile trek to the yard and back, and they haven't come back on.

Granted, I was driving on eggshells going for maximum MPG (http://vehicross.info/forums/showthread.php?threadid=22196), but still... I would think they'd come on if it were something like a gasket leak. I don't know, so here I am.

-V


Yep...

Same experience, as long as I'm a "good boy" with regard to the skinny pedal...nothing.

But when I drive "normally", I would get the same codes. Start with a good maf cleaning...:yesgray:
I had that P1171 code years ago, and it would go away for days, only to return when I took one particular uphill stretch from a right turn. Because it was a 50 mph zone following a blind curve I always had the pedal to the metal. I had the dealership clean the MAF on my next service call, and I replace the K&N filter with a stock one, and have not had another code since.

[Child's Play]

Forgive my waking this tired 'ol thread, but I'm having the EXACT same codes thrown at the moment.

P1171 - Fuel System Lean During Acceleration
P0157 - O2 Circuit Low Voltage (Bank 2 Sensor 2)
P0137 - O2 Circuit Low Voltage (Bank 1 Sensor 2)

My wrench swears up and down that he already replaced all the O2 sensors with brand new ones. He's at a loss. Therefore I am at a loss.

Snowtrooper, can you put please a ribbon on this one and tell us if and how you solved this set of codes?

Thanks,
-V


V,
Just got the same code today as well.... Must be the nice weather. Anyway, on my last VX I had this code as well and it was the intake gaskets (very common). I'm gonna take mine in shortly to have it diagnosed, but I'm pretty positive this is what it is as I hear a slight vacuum sound coming from the engine bay.

What is the mileage on your VX? Mines @ 72K

CP

[Vendetta]

Hey CP,

I'm at 90K now. And the CEL is doin' its thing. I've cleared it a few times, but like Dub says, when I get on it a bit, the light comes right back on and stays on 'til it's cleared.

I'll have my guy look at the gasket leaks - eventually.
-V

[89Vette]

Hey CP,

I'm at 90K now. And the CEL is doin' its thing. I've cleared it a few times, but like Dub says, when I get on it a bit, the light comes right back on and stays on 'til it's cleared.

I'll have my guy look at the gasket leaks - eventually.
-V

If you've got a propane torch, just turn it on and run it around the perimeter of your intake. If the engine speeds up, you've got a leak. Some people use starter fluid, but it can be a fire hazard if you've got spark exposure.

[Vendetta]

Good tip. Sounds like an even better option than spraying cleaner around it. I'd hate to make a clean spot!

I'm putting on a supercharger in the coming weeks (months?) so this might be a moot point, but I'll probably still try it.

-V

[Ldub]

Good tip. Sounds like an even better option than spraying cleaner around it. I'd hate to make a clean spot!

I'm putting on a supercharger in the coming weeks (months?) so this might be a moot point, but I'll probably still try it.

-V

DOOD...:eekgray:

You just jarred some cobwebs off the noggin...:thanx:

I just found my Alpine S/C install material in the garage this weekend.

Scanned & converted to pdf, & shipped it off to the Boss for the DL section.

I know how busy he is, especially right before Moab, so if you want me to email you the files, lemme know...:yesgray:.:_wrench: