1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Po171 I'm at a Lose.

Discussion in '1st Gen. Tacomas (1995-2004)' started by ChiefThickums, Nov 21, 2010.

  1. Nov 21, 2010 at 10:25 AM
    #1
    ChiefThickums

    ChiefThickums [OP] Scrub

    Joined:
    Dec 1, 2009
    Member:
    #26851
    Messages:
    29
    Gender:
    Male
    First Name:
    Tyson
    San Luis Obispo
    Vehicle:
    Bad Ass Gen I
    6 in' Trailmaster, 33x12.50's, TRD supercharged, flowmaster, K&N. Used abused and put away wet.
    Code Po171 Lean fuel bank 1... I've researched the crap out of this topic, and I've found that normal causes are PCV valve, MAF clean or replace, bank 1 O2 sensor bad, engine coolant sensor, fuel filter, low fuel pressure, vacuum leaks and clogged injectors.

    I have a 99 Tacoma 3.4, with a K&N CIA, a supercharger, Flo Master exaust. I got to get this bad boy thru the California smog rape so I got to get this code to go away.. so here's what I've done.

    I've Changed the PCV valve
    Changed Bank 1 O2 (and bank 2 not that it matters)
    Cleaned the MAF (didn't work), then changed MAF
    Changed my Fuel filter
    Triple checked for vacuum leaks
    Replaced the seal around my MAF

    here's the odd part that I don't get but may help some real smart techy type guy figure it out. Most people complain of this code setting when they "really punch it". I can drive like a fool for 200 miles straight and I won't get the Po171 code set but if I let the truck Idle for 10 mins it sets everytime... my truck idles at 750 to 1k RPMs which is a tad high becuase the norm is 650 to 800rpm so according to the book. Makes me wonder is the something to do with the AIC vavle? is there a way to test the coolant temp senor with out replacing it?

    If i can't figure it out i might just turn up my idle just to get it thru.. Im hoping to get it fixed proper if possible tho.. what do you guys think?
     
  2. Nov 21, 2010 at 10:43 AM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

    Joined:
    May 8, 2008
    Member:
    #6497
    Messages:
    106,149
    Gender:
    Male
    First Name:
    FlimFlubberJAM
    Tenoe, AZ
    Vehicle:
    2013 Rubicon Unlimited,
    4.10 gears, sliders, and lots of buttons.
    Cmack had the same problem, and did the same things to fix it, but it kept comming back. He then replaced the MAF, and its been clear ever since..
     
  3. Nov 21, 2010 at 10:49 AM
    #3
    ChiefThickums

    ChiefThickums [OP] Scrub

    Joined:
    Dec 1, 2009
    Member:
    #26851
    Messages:
    29
    Gender:
    Male
    First Name:
    Tyson
    San Luis Obispo
    Vehicle:
    Bad Ass Gen I
    6 in' Trailmaster, 33x12.50's, TRD supercharged, flowmaster, K&N. Used abused and put away wet.
    Yeah I was hoping it was going to be that e-z but no of course not. I replaced the MAF yesterday and I just got the same code after idling for 10 min's.. so I put my old one back in and I'm gunna return it lol.
     
  4. Nov 21, 2010 at 11:00 AM
    #4
    jdtemple

    jdtemple Well-Known Member

    Joined:
    Apr 19, 2010
    Member:
    #35623
    Messages:
    517
    Gender:
    Male
    Bay Area CA
    Vehicle:
    08 DBLCAB LB TRD Sport
    Lift & Tires, in cab power outlets, Locking Bed Boxes, K&N
    Have you tried spraying water or some sort of carb cleaner around the gaskets behind the MAF to see if the idle changes. Could be sucking air from somewhere else.
     
  5. Nov 21, 2010 at 11:07 AM
    #5
    ChiefThickums

    ChiefThickums [OP] Scrub

    Joined:
    Dec 1, 2009
    Member:
    #26851
    Messages:
    29
    Gender:
    Male
    First Name:
    Tyson
    San Luis Obispo
    Vehicle:
    Bad Ass Gen I
    6 in' Trailmaster, 33x12.50's, TRD supercharged, flowmaster, K&N. Used abused and put away wet.
    thoery being that it will suck in the cleaner and make the make a richer mixture and make the truck idle faster? no i haven't but i did just replace the gasket under the MAF. I'll try it that tho sounds like a good idea.
     
  6. Nov 21, 2010 at 11:18 AM
    #6
    ktmrider

    ktmrider Senior Member

    Joined:
    Jul 20, 2009
    Member:
    #19933
    Messages:
    4,969
    Gender:
    Male
    Vehicle:
    07 DCLB 4x4 Sport S/C
    Junk
    I would try ether instead of carb cleaner
     
  7. Nov 21, 2010 at 11:21 AM
    #7
    ChiefThickums

    ChiefThickums [OP] Scrub

    Joined:
    Dec 1, 2009
    Member:
    #26851
    Messages:
    29
    Gender:
    Male
    First Name:
    Tyson
    San Luis Obispo
    Vehicle:
    Bad Ass Gen I
    6 in' Trailmaster, 33x12.50's, TRD supercharged, flowmaster, K&N. Used abused and put away wet.
    I tried striaght up gasoline. nothing. must be nice and sealed.
     
  8. Nov 21, 2010 at 2:13 PM
    #8
    magog45

    magog45 Well-Known Member

    Joined:
    Dec 1, 2009
    Member:
    #26811
    Messages:
    455
    Gender:
    Male
    Canada, just south of Santa
    Vehicle:
    98 tacoma 4x4 extended cab
    5100's all around, 2 inch lift, polyurethane body mounts, gibson exhaust, variation of the deckplate mod, intake resonators removed
    Try blocking the intake at the air filter a bit at a time and see what the idle does, there are lots of places air could be getting in to cause a lean condition. I once had a small cut in the hose for the pvc valve and it caused all kinds of strange idle behaviour.
     
  9. Nov 21, 2010 at 3:04 PM
    #9
    ChiefThickums

    ChiefThickums [OP] Scrub

    Joined:
    Dec 1, 2009
    Member:
    #26851
    Messages:
    29
    Gender:
    Male
    First Name:
    Tyson
    San Luis Obispo
    Vehicle:
    Bad Ass Gen I
    6 in' Trailmaster, 33x12.50's, TRD supercharged, flowmaster, K&N. Used abused and put away wet.

    I don't understand what I'd be looking for If I blocked my air filter a little bit at a time. what would I be looking for if I did that? is that to try and make it suck more obviously thru a possible leak?

    My truck's Idle is actually nice and smooth and never stumbles. It just so happens that the Po171 code only sets while idling never while driving.
     
  10. Nov 21, 2010 at 4:49 PM
    #10
    brelandt

    brelandt Well-Known Member

    Joined:
    Jul 21, 2009
    Member:
    #19979
    Messages:
    460
    Gender:
    Male
    First Name:
    Terry
    Dublin, CA
    Vehicle:
    04 Prerunner reg cab SR5
    3" lift front and back
    dirty injector?
     
  11. Nov 21, 2010 at 5:57 PM
    #11
    GA1044

    GA1044 Well-Known Member

    Joined:
    Oct 3, 2008
    Member:
    #9672
    Messages:
    100
    Gender:
    Male
    San Marcos, TX
    Vehicle:
    2002 trd 4x4
    Air Hog, Grey-Wire Mod, Fabtech Coilover 3.5 Lift, Deck Plate Mod, Rear Diff Breather Mod, Magnaflow Exhaust
    if you got your cats replaced, did you replace them with CARB ones. Tacoma has a really bad habit of triping that code if you dont use their CATS, what i did was purchased the URD oxygen sensor simulator and has stopped it from tripping it.
     
  12. Nov 21, 2010 at 8:01 PM
    #12
    ChiefThickums

    ChiefThickums [OP] Scrub

    Joined:
    Dec 1, 2009
    Member:
    #26851
    Messages:
    29
    Gender:
    Male
    First Name:
    Tyson
    San Luis Obispo
    Vehicle:
    Bad Ass Gen I
    6 in' Trailmaster, 33x12.50's, TRD supercharged, flowmaster, K&N. Used abused and put away wet.
    Yeah I'm tryn to avoid injector work.. mainly cuz of the cash that costs but also because it is only at idle not when I'm gunning it around town.

    A Bad Cat can cause that code? I haven't changed my cat but the guy that had it before me may have.. I'm thinking I need one anyways because of a po420 code that I got. I'll have to look more into that.
     
To Top