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Surging/Thrusting Problem Under Acceleration

Discussion in '1st Gen. Tacomas (1995-2004)' started by jberry813, Jan 2, 2013.

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  1. Jan 13, 2013 at 4:00 PM
    #141
    jberry813

    #141
    jberry813 [OP] Professional Fluffer Moderator

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    I traced harnesses as far back as I could without removing everything.

    No, the downstream O2 is only used to measure emissions after cat.
    Ruling it out, disconnected or connected it has no effect on the symptoms.

    I can't find anything in the FSM for that. Doesn't mean it doesn't exist, I just can't find it.
     
    jberry813, Jan 13, 2013
    #141
  2. Jan 13, 2013 at 6:08 PM
    #142
    ian408

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    ian408 Well-Known Member

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    I got nothing. What's weird though is the engine goes into closed loop. So it can't be anything simple like an O2 or temp sensor.

    I'd almost say put it back together and take it someplace they can stick it on the computer.
     
    ian408, Jan 13, 2013
    #142
  3. Jan 13, 2013 at 7:38 PM
    #143
    kickergt

    #143
    kickergt Well-Known Member

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    I have the exact same problem going up hills. I think its the Maf and the computers inability to correct load lol. I'm gonna test it next week with a wideband o2 and see what the AF is doing during the issue
     
    kickergt, Jan 13, 2013
    #143
  4. Jan 13, 2013 at 8:14 PM
    #144
    jberry813

    #144
    jberry813 [OP] Professional Fluffer Moderator

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    Mentally, I'm nearly at that point....
    My truck is all tore apart right now for many reasons outside this thread. If I can't make any headway when I get it back together I may actually shop for a mechanic...something I haven't done in...well...ever. :(

    :spy:

    Well keep us posted!
    As of today, I got a fresh MAF in my truck with zero change in symptoms.
     
    jberry813, Jan 13, 2013
    #144
  5. Jan 13, 2013 at 8:17 PM
    #145
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    On a separate note, I've had 3 (actually 4 counting kickergt above) separate members either text me or PM me since I started this thread saying they have the exact same problem. So at least this thread doesn't seem to be for nothing....
     
    jberry813, Jan 13, 2013
    #145
  6. Jan 13, 2013 at 8:20 PM
    #146
    RAT PRODUCTS

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    RAT PRODUCTS Well-Known Member

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    I asked one of my engine tech buddies and he thinks it's fuel delivery and says test the injectors if you haven't already.
     
    RAT PRODUCTS, Jan 13, 2013
    #146
  7. Jan 13, 2013 at 8:23 PM
    #147
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    Yeah I neglected to mention in the thread that I actually did the injector swap I previously spoke about. I have 4 fuel injectors from my old engine. I swapped out a bank of 3 injectors (drivers side) with my "good" injectors, assembled and test drove with no change.
    Then did the same swap but on the passenger bank of injectors, again no change.
     
    jberry813, Jan 13, 2013
    #147
  8. Jan 13, 2013 at 11:07 PM
    #148
    92shawman

    #148
    92shawman Person

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    I forget, have you ruled out the vacuum pump? I asked my parents what they thought because the used to do a lot of car work (of course, that was with old vw's, not anything new) and their first thought was the vacuum.
    Sorry if that's completely been ruled out already and I missed it somewhere...
     
    92shawman, Jan 13, 2013
    #148
  9. Jan 14, 2013 at 5:54 AM
    #149
    BamaToy1997

    #149
    BamaToy1997 Wheel Bearing Master

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    Let me know what schematics you will need. I can post them up. Right now, as per our PM exchange, I will be looking into the system a bit more. I think we all can agree that it will not be an easy find. What will be the probable result is we find the problem and be all "DOH" We should have thought of that! That is what usually happens. As I have said from early on, I believe that the higher fuel pressure and whatever may be causing the fuel pressure flutter is a big part of the problem. With other people having a similar problem, it would be interesting to know if they ever checked fuel pressure and found that it fluttered on them as well at that same point yours does.
     
    BamaToy1997, Jan 14, 2013
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  10. Jan 14, 2013 at 6:30 AM
    #150
    kickergt

    #150
    kickergt Well-Known Member

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    Are all the cars having this issue forced induction?
     
    kickergt, Jan 14, 2013
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  11. Jan 14, 2013 at 7:08 AM
    #151
    ian408

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    ian408 Well-Known Member

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    What's strange to me is that the truck runs without the surge in open loop. You would think if it were pressure regulator or pump, the surge/flutter would still be there.

    Could it be a hose or fuel line that is pinched or collapsing at higher vacuum pressure? Maybe the fuel return?
     
    ian408, Jan 14, 2013
    #151
  12. Jan 14, 2013 at 7:20 AM
    #152
    kickergt

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    kickergt Well-Known Member

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    00 Tacoma TRD 4x4 329WHP 390Wtq Turbo sucka
    It could be fuel pressure fluctuation under load...... idk
     
    kickergt, Jan 14, 2013
    #152
  13. Jan 14, 2013 at 9:02 AM
    #153
    jberry813

    #153
    jberry813 [OP] Professional Fluffer Moderator

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    I don't think tacoma's actually have a vacuum pump. I could be wrong, but it's been long time since I've seen one of those and those were all early vehicles. Based on fuel pressure test in the truck with the vacuum port disconnected from the FPR, manifold vacuum leak is ruled out.

    As for documents, anything you can find with regards to fuel management and fuel delivery. I have the FSM, but I can't seem to find out what sensors come into play during open/closed loop besides the ones I already know about (A/F M and MAF).

    I'm still heavily leaning towards FPR at this point. As discussed, the fluttereing gauge and high fuel pressure seem to be the focus point. I called URD and talked to Gadget and explained my situation. He said even with his fuel pump, the fuel pressure should be at 43.5 psi when the FPR is vented to atmosphere. If under boost, the FPR will increase 1 psi for every psi of manifold boost. Since I'm back to stock intake manifold and vented to atmosphere, I'm 5 psi too high.

    He recommended I focus on two things....

    1) Get a factory Denso fuel filter. He said he's seen nothing but lean problems from aftermarket filters. Both my previous fuel filters were WIX filters from my local autoparts store. Seems odd that the problem would be experienced well after the first fuel filter change and continue into the new fuel filter, but certainly a possibility.

    2) Focus on FPR and return line. 48> 43.5 and as you said, should not flutter or change.

    No. My truck was experiencing the problem with the S/C and without the S/C.

    Preaching to the choir! Beyond weird.
    It can't be a collapsed line at higher vacuum pressure, because I also had the same problem under boost. Moderate throttle uphill still put me at positive manifold pressure (2-3 psi).

    Well, it is fluttering with the scenario. Just seems so effing weird that it only flutters during the surge and I can lift or go WOT and the fuel pressure goes back to 48 psi.
     
    jberry813, Jan 14, 2013
    #153
  14. Jan 14, 2013 at 9:42 AM
    #154
    ian408

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    ian408 Well-Known Member

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    Hmm...I guess it could be the FPR but in open loop, no problem. And w/o SC, still no problem.

    The one thing that bubbles up for me is that the fuel pump is higher pressure. I don't know what the "ratio" (for lack of a better term) for fuel pressure to spring rate (in the regulator) should be and whether the higher pressure has an effect on it's performance.

    I guess I might wait for the result from the filter change and check the fuel return line. But hey, a FPR is only a $100 or so
     
    ian408, Jan 14, 2013
    #154
  15. Jan 14, 2013 at 10:33 AM
    #155
    3.4v6

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    3.4v6 Well-Known Member

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    Just wondering , if your SC'd where do you have your FPR hooked up? I remember my truck doing this a while ago. Im still trying to remember what i did to cause it to happen and what i did to fix it.
     
    3.4v6, Jan 14, 2013
    #155
  16. Jan 14, 2013 at 10:58 AM
    #156
    BamaToy1997

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    BamaToy1997 Wheel Bearing Master

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    Not strange at all that there is no problem evident in open loop. Fuel injector operation and control are totally different under open loop conditions. That is what we are trying to address right now is what changes during closed loop to cause the fluctuation, and most likely the result being the surge.

    Check the rest of the thread. We have been talking about the fuel pressure fluctuation for some time now...:D

    In reference to bold print: He said it still had the problem without the SC. It just was not as obvious.
    As for ratio of spring pressure to fuel pressure regulation, it is different for different manufacturers, and not part of the information typically given to a tech since we don't rebuild the regulators, we replace them. Would be an interesting idea to find out though.

    A clogged fuel pressure line would cause an increase of pressure, and is something that would be considered. However a clogged return line would NOT cause a flutter in the pressure as he described.

    Jberry, I haven't had a lot of time to look things up. Right now I am on a lunch break trying to get some food and get back to work. I have valve cover gaskets, spark plugs, and a fuel filter to put in an F-150. You would think Ford would be intelligent enough to allow you to remove their coil-on-plug without removing the fuel rail? lol.
     
    BamaToy1997, Jan 14, 2013
    #156
  17. Jan 14, 2013 at 11:28 AM
    #157
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    I looked up the P/N. Eric has the same FPR in his runner that I do. Hoping he can make a trip up or I can drive down later.

    Again, I am not supercharged at the moment. Back to NA.
    But when I was supercharged, FPR was hooked up to the boost port of the s/c. Fuel pressure in that scenario is supposed to be +1 psi of fuel pressure for every +1 psi of manifold pressure. Right now FPR is vented to atmosphere.

    Nothing surprises me with Ford. :eek:
     
    jberry813, Jan 14, 2013
    #157
  18. Jan 14, 2013 at 11:42 AM
    #158
    ian408

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    ian408 Well-Known Member

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    I wasn't clear about the context of my comment. When I said "no problem", I meant with fuel pressure. Sorry about that.

    If the fuel supply line is clogged, shouldn't you read a lower pressure at the fuel rail (or the inability to maintain the pressure as load increases)? And wouldn't a clogged fuel return cause an increase in pressure (similar to disconnecting the vacuum line from the FPR)?
     
    ian408, Jan 14, 2013
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  19. Jan 14, 2013 at 5:42 PM
    #159
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    Found this little jewel in the FSM.

    ScreenHunter_01 Jan. 14 17.30.jpg


    Pulled the circuit opening relay and hotwired the fuel pump on with ignition. Took it for a spin...no change. Means FC output from ECM is fine. Also metered FC while driving and it never got above .05 volts which isn't enough to turn the relay off....can rule that out too.

    On a long shot I also set the crank pulley at 0 and pulled the upper timing belt cover off far enough back to check the timing marks on the cams. Everything is dead nuts center as I expected.

    Emptied a bottle of carb cleaner and a small propane bottle hunting for vacuum leaks. Not a single fuck given by the engine....

    I'm undecided at this point whether I'm going to
    1) Burn thru the 1/4 tank of gas I have and drop the tank and swap fuel pumps with the factory one
    2) Pick up a brand new FPR and fuel filter from Toyota (another $165 guess from Camelback Toyota)
    3) Burn the fucker to the ground
    4) Take it to a mechanic
     
    jberry813, Jan 14, 2013
    #159
  20. Jan 14, 2013 at 5:45 PM
    #160
    disc0monkey

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    Did you Vacuum test the Pcv
     
    disc0monkey, Jan 14, 2013
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