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2.7L auto weak with error code p0402 "EGR EXCESSIVE FLOW"

Discussion in '1st Gen. Tacomas' started by outlaw8950, Mar 18, 2010.

  1. Mar 18, 2010 at 11:24 PM
    #1
    outlaw8950

    outlaw8950 [OP] New Member

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    Marshall
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    My '99 PreRunner has been weak for a long time and the gas mileage has always sucked. The CEL recently came on and the P0402 code comes up on the code scanner. What would cause this? Could the converter be partially plugged or even the muffler causing too much back pressure? If so how can I check the back pressure?
    My truck has 165,000 on it and is a 2.7L with an auto. I also wonder how much effect the 31/10.50's have on it's power with stock gearing. It's always been weak since I bought it with 114,000 and the 31's were already on it.
    What gears should be in it stock and what ratio could be installed to theoretically put it back to stock with the 31's? I like the look of the 31's but it know that they make it weaker.
    My truck blows some black smoke occasionally on start-up as if an injector is going bad and leaking into the cylinder. This could be some of the problem. What lb/hr are the injectors?

    Any info from ya'll will be greatly appreciated. I'm new to the site and I've been reading a lot of good info posted on here.

    Thanks in advance Marshall
     
  2. Mar 19, 2010 at 12:03 AM
    #2
    kilgoja

    kilgoja Well-Known Member

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    prolly something the dealer is gonna have to fix for you...could be a bad egr valve or something
     
  3. Mar 19, 2010 at 12:24 AM
    #3
    thisERICtaco

    thisERICtaco Well-Known Member

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    sounds like you have a bad pcv system for the black smoke problem
    and for the egr code
    the egr is probably stuck either open or closed
    if its open then your getting a shitty idle
    if its stuck closed then you get shitty mpg
    but all in all
    either clean the egr
    or clean the egr lines
    thats one of the main reasons it does that cause of to much carbon build up or the exhaust being backed up into it
    just read the topic again ahah its excessive flow
    so its stuck open
    so clean it out and you should be fine
    run seafoam through your system to clean our the injectors and clean out the throttle body
    seems like you need a tune up =]
     
  4. Mar 19, 2010 at 10:52 AM
    #4
    outlaw8950

    outlaw8950 [OP] New Member

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    Idles fine and I put a vacuum hose on the EGR and sucked on it while idling and it started running rough when the EGR valve opened. I feel like it might be more of a back pressure issue with either the cat or muffler but I'm going to take the EGR off and clean it anyway this weekend.

    I've put some BG brand injector cleaner in the tank and I think I'll get some Sea Foam and try it too. Wires and plugs have been recently replaced, I need to put a new fuel filter in for good measure.

    I think the 31's are dragging it down some, espaecially with it being an automatic.
     
  5. Mar 19, 2010 at 12:58 PM
    #5
    thisERICtaco

    thisERICtaco Well-Known Member

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    i suppose
    usually something is keeping it open since it says excessive flow
    so maybe while your driving and it opens it stays stuck for a little while and then finally snaps back into place
    just check the lines and try to clean out the egr and that might fix it
    good luck
     
  6. Sep 1, 2010 at 5:43 AM
    #6
    SteveNC

    SteveNC Member

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    Did you ever figure out what was causing the P0402 excessive flow?

    I've tested and cleaned the EGR valve and everything is fine with it. Also replaced the PCV which was bad. Check engine light for 402 keeps coming back on. Seems to come on when the engine is cold: less than a block from my house usually in the morning after sitting overnight. if code cleared and truck warm it doesn't come on; at least not yet.

    I plan to test the temp sensor for the EGR, but I'm thinking if not that maybe the EGR Vacuum Modulator Valve may be bad. Any suggestion?

    I'm on the forums because I'm not willing to take to dealer yet. Haynes manual is pretty much useless since it covers so many years and tends to ignore the 2.7l 4 cyl engines.
     
  7. Sep 1, 2010 at 9:37 AM
    #7
    shampoop

    shampoop Well-Known Member

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    egr isn't supposed to be on at all until your car is warmed up iirc. so any flow would be excessive. so whatever tells the egr when to turn on may be at fault.
     
  8. Sep 1, 2010 at 9:49 AM
    #8
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

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    http://www.ncttora.com/fsm/2003/Repair_Manual/03tacoma/di/eg2rzfe3/cip0402.pdf

    It could be the EGR temp sensor. You check it with an OHM meter. It should read 2.5k Ω. If it reads 200 or less, it is shorted.

    http://www.ncttora.com/fsm/2003/Repair_Manual/03tacoma/ec2rzfe3/egrsy/insp.pdf

    There is also a VSV (vacuum switching valve) that operates the EGR. It could be faulty.

    http://www.ncttora.com/fsm/2003/Repair_Manual/03tacoma/ec2rzfe3/plasd/draw.pdf


    The simple check is to insure all of your vac lines are good and connected.
     
  9. Sep 1, 2010 at 8:40 PM
    #9
    SteveNC

    SteveNC Member

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    Thanks 98tacoma27, that was my next thing, but I can't find where it is located on my truck using any of the illustrations I've seen. Do you know where I might find that on the 2.7l w/4wd? Is it one three sensors attached to the charcoal canisters on the drivers fender?

    I tested the egr temp sensor tonight and it is within expected range for the temp of my intake manifold. Within spec at 125 degrees F so I'm confident it can't be that. I'll check it again in the morning when completely cool, but I'd be surprised if it were off but dead on at 125 deg. Just isn't typical for a simple circuit like that.

    I also applied vac to the EGR Vac Modulator valve and checked for flow changes and that device also appears to be OK. I guess I'm on to the VSV if I can locate it.
     
  10. Sep 5, 2010 at 6:34 PM
    #10
    SteveNC

    SteveNC Member

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    located the VSV for EGR deep inside the intake manifold. Not the kind of job to do when the engine is even a tiny bit warm. tested it according to specs and the first time the Ohms tested OK, as did air flow. when applying power to the VSV it worked right the first time but then tried again and it didn't open/close. checked Ohms again and it failed. called first dealer, they were out of stock but could order for 83, they told me another dealer had it in stock; went there and they wanted nearly 120 for it and had to talk them down. learned two valuable lessons; don't try to change the VSV when engine is warm, and comparison shop each Toyota dealer when buying OEM parts. 0402 code hasn't come back on, but it has only been two days. hopefully that took care of it.
     
  11. Sep 6, 2010 at 8:31 AM
    #11
    outlaw8950

    outlaw8950 [OP] New Member

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    Steve, With the 0402 code showing excessive flow cause a power loss? What if I block off the EGR completely?
     
  12. Sep 6, 2010 at 9:17 AM
    #12
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Staff Member

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    If you block it off, Your Cumbustion chamber temps will be higher, possibly resulting in pre detonation, poor idle.
     
  13. Sep 8, 2010 at 4:25 AM
    #13
    SteveNC

    SteveNC Member

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    I didn't notice a huge difference in power but mine was intermittent and my wife drives the truck more often than me. She said it didn't feel as strong. Since the mileage in city driving dropped to 15.5 MPG which is about 1 mpg worse than running in 4WD that tells me it did loose power. Much more fuel used for the same amount of work/distance.

    I personally would not block off the egr or the vsv for egr. That would just cause it to throw different codes. Plus with the increased fuel consumption I would expect the converters and possibly O2 sensors to fail sooner from the excess carbon and and higher exhaust temps.
     
  14. Dec 1, 2010 at 10:20 AM
    #14
    chrisx1

    chrisx1 Well-Known Member

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    Did either of you ever solve your P0402 code problems?

    I just popped the same code, and it was when the truck was cold as well.
     
  15. Dec 2, 2010 at 9:20 AM
    #15
    SteveNC

    SteveNC Member

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    yes, it ended up being that VSV for EGR vacuum switch. it has been months and the light hasn't come back on and it passed state smog inspection.
     
  16. Dec 3, 2010 at 10:25 AM
    #16
    StAndrew

    StAndrew Wait for it...

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    I have the same code for my 3.4L. Where is the EGR valve located and how do I clean it? Can I use manifold intake cleaner spray or MAF cleaner?

    Thanks.
     
  17. Dec 3, 2010 at 10:32 AM
    #17
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

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    The 3.4 doesn't have an EGR valve.
     
  18. Dec 5, 2010 at 1:28 PM
    #18
    StAndrew

    StAndrew Wait for it...

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    I keep getting a pending P0402 code from my Ultra Gauge. I ignore it as no engine lights comes on, however I thought it might have to do with this... What else could it be?
     
  19. Dec 9, 2010 at 5:32 PM
    #19
    SteveNC

    SteveNC Member

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    On a 3.4l? I'm not sure - I know that on the 2.4l that code indicates "Exhaust Gas Recirculation Flow Excessive Detected (Only for 3RZ–FE)" according to the shop manual. Shop manual goes on to say that it could be the following likely causes:
    - Short in EGR gas temp. sensor circuit
    - ​
    EGR gas temp. sensor
    - Open in VSV circuit for EGR

    - VSV for EGR

    - EGR valve stuck open
    - ECM

    I tested each but, not in the order they list because I couldn't see the VSV. When I found the VSV I tested it several times and found that sometimes it passed and sometimes it didn't.

    If it is a pending code I wouldn't worry about it until it actually makes the check engine light come on and stay on. If I understand the computer system correctly it has to read the fault code twice before activating the check engine light. IMHO it is too time consuming to find an intermittent problem unless you it is acting up when I'm testing. ​
     
  20. Apr 12, 2011 at 8:20 AM
    #20
    stephan305

    stephan305 Active Member

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    i have a 99 toyota prerunner with 31s b/f goodrich tires.and there are no problems at all with that size tire.anything bigger would be.my erg just went out,and my engine does not run as smooth,and smells a little burnt.128.000miles and never had any major problems.its moost likely your erg valve.you will get more knock and more smoke.
     
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