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

[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.



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