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

Zero vacuum at fuel pressure regulator???

Discussion in '4 Cylinder' started by mytoy04, Mar 14, 2014.

  1. Mar 14, 2014 at 10:48 AM
    #1
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    I have a 99 4runner with the 2.7 5sp 4x4, 140k. Ive started having a stumbling issue in 4th and 5th gear like when pulling a hill, like it cuts out and if I let off it stops and ease back its fine, put when try to accelerate to get going it stumbles. No check engine lights on either. My fuel mileage has dropped from high 19's to 14.5. I have new NKG plugs cleaned MAF and the throttle body. Also checked the fuel pressure regulator when I noticed no vacuum on the line from the intake tube. I thought that had constant vacuum? So in my research i've found out where the fuel filter is and read that they are suppose to be lifetime? Never heard of that. Also found some stuff on the VSV and egr valve stuff. I'm not familiar with either. So is one of those two items why I don't have vacuum at the fuel pressure reg. or are they not realated? I don't see a shratter valve to test fuel pressure or how to test the VSV and or clean the EGR valve. Am I looking at the right stuff that mite be causing the stumbling and drop in fuel mileage? Any help on this would be awesome, thanks y'all.
     
  2. Mar 14, 2014 at 2:05 PM
    #2
    hoenah808

    hoenah808 Well-Known Member

    Joined:
    Jan 26, 2014
    Member:
    #121533
    Messages:
    603
    Gender:
    Male
    Honolulu, HI
    Vehicle:
    '14 AC sr5 4x4
    last I remember I heard of cracked exhaust manifolds causing similar issues....might wanna check that out
     
  3. Mar 15, 2014 at 9:26 AM
    #3
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Thanks, can someone provide pics of how to test the fuel pressure on these 2.7s? And are these fuel filters really suppose to be lifetime? I just need to get a Haynes manual I guess. This no vacuum at the box under the air intake tube is weird to me, how is the fuel pressure regulator suppose to work without vacuum to it?
     
  4. Mar 15, 2014 at 10:27 AM
    #4
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Any chance someone could check their vacuum at the fuel pressure regulator and at that box that hangs under the air intake tube and then reply, please! :). I'm really confused about this i dont know if it only creates a vacuum at high rpms or what? My truck has vacuum at the FPR at idol, so I'm stumped. Thank for any help here.
     
  5. Mar 15, 2014 at 10:50 AM
    #5
    BamaToy1997

    BamaToy1997 ASE Master Tech Vendor

    Joined:
    Jan 31, 2012
    Member:
    #71846
    Messages:
    9,424
    Gender:
    Male
    First Name:
    Bill
    Navarre, FL
    Vehicle:
    1997 Tacoma 4X4 AKA "Blue Beast"
    Multi-point tow hooks, new bored 2.7L engine, custom paint. 3 inch adjustable Fabtech front coils, 2.5 inch rear AAL. Front Aussie locker. LED bed lights. Full LED conversion interior and exterior. Relentless Fabrication front and rear bumpers. 4X4innovation sliders. BAMF bed rack. CVT rooftop tent.
    The 2.7 has an unusual style of operating the fuel pressure regulator. The vacuum line is not connected to a port on the throttle body. Instead it is connected to a port in the intake air chamber. The system uses the venturi effect to create a vacuum at the vac line to the FPR. This means you typically won't be able to "feel" a vacuum on the line like you typically expect. You can however measure it with a vacuum gauge.
     
  6. Mar 15, 2014 at 11:20 AM
    #6
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Interesting. Thanks BamaToy1997. So am I on the right track for the stumbling issue and poor fuel mileage? And do you suspect they are related?
     
  7. Mar 15, 2014 at 11:30 AM
    #7
    BamaToy1997

    BamaToy1997 ASE Master Tech Vendor

    Joined:
    Jan 31, 2012
    Member:
    #71846
    Messages:
    9,424
    Gender:
    Male
    First Name:
    Bill
    Navarre, FL
    Vehicle:
    1997 Tacoma 4X4 AKA "Blue Beast"
    Multi-point tow hooks, new bored 2.7L engine, custom paint. 3 inch adjustable Fabtech front coils, 2.5 inch rear AAL. Front Aussie locker. LED bed lights. Full LED conversion interior and exterior. Relentless Fabrication front and rear bumpers. 4X4innovation sliders. BAMF bed rack. CVT rooftop tent.
    It is very possible. The best way to know for sure is check ALL reading on the scangauge and compare to expected results.
     
  8. Mar 15, 2014 at 11:53 AM
    #8
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Yea I've been checking the parameters with my scan gauge but not sure what some of the readings are suppose to be reading. Like I can read fuel trims and o2 volts and stuff and my research has let me to believe its good. My cat got stolen so it's new with new o2 sensors, so that should be good. I don't know if it's the fuel filter or EGR or VSV solenoid. Was gna check the fuel pressure but not sure how with no port to hook to.
     
  9. Mar 24, 2014 at 8:26 AM
    #9
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    UPDATE: Well this issue has finally caused my check engine light to flash. We was on our way to a wedding and it started bucking, or stumbling at highway speeds when trying to accelerate or maintain speed going up a hill. Cel started flashing and then stopped. Left the wedding and reception and had about a 20 min drive home and no check engine light, and it never stumbled once and has been fine since. Tried to pull a code and no codes stored. My research led me to believe its a misfire. I checked my plug wires with voltmeter and the ohms was like 11.5 on the long #4 wire down to about 6.75 on the shortest #1 wire. Had good spark on the wires to the coil packs but not real sure my test for those was correct. Anyway anybody have any thoughts?
     
  10. Mar 24, 2014 at 12:40 PM
    #10
    hoenah808

    hoenah808 Well-Known Member

    Joined:
    Jan 26, 2014
    Member:
    #121533
    Messages:
    603
    Gender:
    Male
    Honolulu, HI
    Vehicle:
    '14 AC sr5 4x4
    u changed the plugs...did u buy new wires?
     
  11. Mar 24, 2014 at 2:18 PM
    #11
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    I did not. Shame on me, I know. I was going of how they looked and they look brand new. I did inspect them and was and are in really good shape. I've never noticed any improvement in the past when changing plugs and wires. I just read somewhere that if the plug wires say what cylinder they go to then they are originals!!!! Yikes, 140k miles. But I just checked for spark leakage with a spray bottle and couldn't see any sparks and of course I also just did the ohms check. Can't find any info in my Haynes manual that says what the ohms should be on the plug wires and a google search is all over the map on what they should be. I will buy new plug wires but not real sure it will fix my "fish biting"
     
  12. Mar 24, 2014 at 3:22 PM
    #12
    hoenah808

    hoenah808 Well-Known Member

    Joined:
    Jan 26, 2014
    Member:
    #121533
    Messages:
    603
    Gender:
    Male
    Honolulu, HI
    Vehicle:
    '14 AC sr5 4x4
    do you know which cylinders are misfiring? try swapping the coils around and see if you can point them out.
     
  13. Mar 24, 2014 at 3:49 PM
    #13
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    No I don't. The CEL just flashed for like a minute or less then stopped. I was hoping it would've left a code but it didn't. I didn't have my code reader hooked up at the time and I guess since it just flashed it didn't store a code. My Haynes manual isn't real clear on how to test the ohms on the coils for the primary and secondary. It shows how to test that the coils are getting power but not the resistance. Do you know how to test the coils with a voltmeter?
     
  14. Mar 25, 2014 at 12:14 PM
    #14
    tan4x4

    tan4x4 Well-Known Member

    Joined:
    Nov 30, 2011
    Member:
    #67982
    Messages:
    1,901
    Gender:
    Male
    First Name:
    Rick
    Folsom, CA
    Vehicle:
    99 Tacoma EC 4x4 2.7L Auto
    Bilsteins, OME 881's, 3-leaf AAL, Detroit TruTrac, 31" tires, Michelin LTX AT2, stock gears, Tranny skidplate, TC skidplate, CBI rear bumper, sliders, UltraGauge, PowerTank, CB
    My Ultragauge can detect 'pending' codes (before it throws a CEL). Does the Scangauge do that?
     
  15. Mar 25, 2014 at 12:40 PM
    #15
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Well I'm not sure if the Scanguage does or not. I guess I just have a scan tool. I bought an Elm WIFI adapter and an app on my phone. It does scan codes and parameters. I was gonna get the Ultraguage but a guy told me about this adapter thing so went with the $20 adapter and $10 app. I did go to the parts store to see if the flashing check engine light left a code and they scanned and confirmed, no code.
     
  16. Apr 1, 2014 at 5:56 AM
    #16
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Another UPDATE: Well finally got a check engine light on the other day. P0300 and P0301. So I pulled the spark plugs again and #1 looked pretty dark while the other 3 looked great. So I went ahead and replaced the wires and all new plugs but now I have a rough idle on the first start in the am. If you tap the gas a couple times it clears up and rides out great. So any thoughts? Is this another new problem or still dealing with the misfire? I'm still not sure how the check the coil packs. Remebering I did clean the MAF and throttle body so not sure what to look at next. I really thought changing that burnt looking #1 plug was the problem but now I'm curious if that was the affect of something else being bad, like the wires, but now not sure what to think. Thanks for any input.
     
  17. Apr 2, 2014 at 10:03 AM
    #17
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Well I give up. To the shop it goes. Goes in friday so if anybody is following this I will update with the findings. Be back in a couple days.
     
  18. Apr 5, 2014 at 3:23 PM
    #18
    mytoy04

    mytoy04 [OP] Well-Known Member

    Joined:
    Jun 26, 2009
    Member:
    #18933
    Messages:
    50
    Gender:
    Male
    First Name:
    Tim
    Liberty, MO
    Vehicle:
    99 4Runner 4cyl 5sp 4x4
    Well.... The report is in, and it's not good. Blown head gasket! $1100. I'll try to remember to report back with the mpg gained back, if indeed it goes back to the high 18s and 19s that is. Thanks to everyone for chiming in.
     
  19. Apr 6, 2014 at 8:40 AM
    #19
    tan4x4

    tan4x4 Well-Known Member

    Joined:
    Nov 30, 2011
    Member:
    #67982
    Messages:
    1,901
    Gender:
    Male
    First Name:
    Rick
    Folsom, CA
    Vehicle:
    99 Tacoma EC 4x4 2.7L Auto
    Bilsteins, OME 881's, 3-leaf AAL, Detroit TruTrac, 31" tires, Michelin LTX AT2, stock gears, Tranny skidplate, TC skidplate, CBI rear bumper, sliders, UltraGauge, PowerTank, CB
    Bummer :(

    This likely goes without saying, but be certain that they use brand new head bolts, and that they check the head for worn/burnt valves, etc.
     
To Top