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Surging/Thrusting Problem Under Acceleration

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

Page 5 of 14
  1. Jan 3, 2013 at 3:11 PM
    #81
    StAndrew

    #81
    StAndrew Wait for it...

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    Intake, exhaust, lift. Typical stuff.
    Excuse me for not reading all pages,

    I say it has to be fuel delivery. Maybe bad pump. Maybe bad ECU too.

    If its not the engine, maybe check for slipping clutch???
     
    StAndrew, Jan 3, 2013
    #81
  2. Jan 3, 2013 at 3:24 PM
    #82
    disc0monkey

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    disc0monkey All right. I believe ya. But my Tommy Gun don't!

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    are you really getting knock? pull the plugs, do you have metallic on the ceramic?

    maybe you have bad knock sensors.
     
    disc0monkey, Jan 3, 2013
    #82
  3. Jan 3, 2013 at 4:49 PM
    #83
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    Thanks either way!

    Fuel pump is less than 2 years old. More on that in a minute....

    Clutch is tits. No slipping in any gear, even if I try to make it slip.

    When I had the s/c on, i thought I heard it ping (spark knock) going up a steep grade at WOT. Since removing the sc, I haven't heard any pinging.
    As mentioned earlier, plugs are brand new, factory recommended NGK BKR5EKB–11.
     
    jberry813, Jan 3, 2013
    #83
  4. Jan 3, 2013 at 5:39 PM
    #84
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    Alright, so I attached the fuel inspection section of the FSM.
    http://www.tacomaworld.com/forum/attachment.php?attachmentid=187991&stc=1&d=1357260589

    Rather than pulling all the timing cover shit off to check fuel pressure, I just used the T I already had in my fuel line for the 7th injector to connect the fuel pressure gauge.

    As it turns out, the fuel pump on the taco doesn't turn on until the truck is starting/running despite the key being in the on position. And since I know the fuel pump actually works (my truck runs....), I basically skipped steps 1-2(l).

    That said, starting from 2(m), I measured fuel pressure at idle with the vacuum sensing hose disconnected. I measured 48 psi. FSM says acceptable ranges are from 38-44 psi.

    I connected the fuel pressure regulator to a vacuum port on the intake with a brand new vacuum line, and the fuel pressure dropped to 44 psi. FSM says acceptable range is 33-38 psi.

    Turned off the truck and let it sit for 5 minutes. Fuel pressure only dropped to 40 psi. FSM says should be 21 psi or more.

    So, since it's not low fuel pressure, I'm guessing we can eliminate fuel pump, fuel filter (as it's brand new anyway), and fuel lines as being the culprit.

    As for the slightly higher than specified fuel pressure, can that be attributed to a larger fuel pump than factory?
     

    Attached Files:

    jberry813, Jan 3, 2013
    #84
  5. Jan 3, 2013 at 5:42 PM
    #85
    blake5995

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    blake5995 Well-Known Member

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    yea the higher pressure is because of your aftermarket fuel pump which shouldn't do anything bad
     
    blake5995, Jan 3, 2013
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  6. Jan 3, 2013 at 6:13 PM
    #86
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    Nice to see you come out of the wood works to help out pops. <3
     
    jberry813, Jan 3, 2013
    #86
  7. Jan 3, 2013 at 7:52 PM
    #87
    92LandCruiser

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    92LandCruiser Well-Known Member

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    just fyi...

    graphing meter or whatever is a lab scope it's like a super sensitive volt meter that graphs it. They're generally really expensive.

    Washoe and Clark have smog check BS. Might be able to find a mechanic near you that has one anyway, just for diagnostic purposes.
     
    92LandCruiser, Jan 3, 2013
    #87
  8. Jan 3, 2013 at 8:31 PM
    #88
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    As requested by Alex, a short video of the problem.
    Skip till after I shift into third around 5 second mark. Around 15 second mark is where you can hear the problem most noticeably if you're listening to the sound of the intake. The back and forth of the camera is from the thrusting the truck is making.

    I drove the naturally aspirated truck anywhere I went today. It's most noticeable in second and third gears between 2200 and 3000 rpm mid throttle going uphill. It's been a LONG time since I drove an unsupercharged 1st gen, so I can't tell you if it's any more gutless than when I first got the truck.

    http://www.youtube.com/watch?v=n7cI4M-3g-w
     
    jberry813, Jan 3, 2013
    #88
  9. Jan 3, 2013 at 9:23 PM
    #89
    NW4RUNNER

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    NW4RUNNER Well-Known Member

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    I'm certainly not a mechanic, but if you've about ruled out fuel system problems, and your confident its not throttle, it sounds electrical. Maybe fried ECU? If there was a problem within the ECU, it could be made worse with the 7th Injector wired into it as well.
     
    NW4RUNNER, Jan 3, 2013
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  10. Jan 3, 2013 at 9:30 PM
    #90
    jberry813

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    Fuel problems have not been ruled out, just SOME of the fuel problems have been. Fuel pressure regulator and injectors are still subject, as is the TPS outlined in the previously linked thread.

    The hose on the fuel pressure gauge test kit is pretty gnarly. If I have some time tomorrow or early Saturday, I'm gonna take it for a spin with the gauge in the cab to see what it's doing while the problem occurs. There's a perfect hill that I can reproduce the problem every time only a few blocks from my house.

    And the URD kit is damn solid. Only issues I've ever heard of it have been from miss-installations.
     
    jberry813, Jan 3, 2013
    #90
  11. Jan 3, 2013 at 10:21 PM
    #91
    12TRDTacoma

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    If fuel delivery has been ruled as okay yyou might want to recheck spark make sure that air gap is good and strong. If not, suspect weak coil or coils. Check the fuel pressure and make sure iit is 100% good. What is your mileage and year of the car?
     
    12TRDTacoma, Jan 3, 2013
    #91
  12. Jan 3, 2013 at 10:53 PM
    #92
    Shaggs

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    Shaggs Well-Known Member

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    I still think its TPS or TB related... Is there seriously nobody in Tahoe with a Scangauge2? Would tell you if it's input error or on throttle body side.
     
    Shaggs, Jan 3, 2013
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  13. Jan 3, 2013 at 11:13 PM
    #93
    ian408

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    ian408 Well-Known Member

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    It sure feels like a regulator. But you're right that S2 would help get that settled.
     
    ian408, Jan 3, 2013
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  14. Jan 3, 2013 at 11:15 PM
    #94
    Anthony250

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    Anthony250 Ex Fabricator

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    Hmm After Listening to that video I could almost swear my truck does that as well at times.
     
    Anthony250, Jan 3, 2013
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  15. Jan 3, 2013 at 11:46 PM
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    jberry813

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    ...too much shit to list.
    Ok so get this.

    I just hooked up the full pressure test kit again and snaked the gauge into the cab of the truck. Fuel pressure is consistently at 48 psi EXCEPT when the surging happens. When the surging happens the hardest, the fuel pressure gauge flutters ridiculously fast between 42-48 psi. I mean so fast I almost didn't notice it at first. I did 4 passes up and over the hill in third gear and every time the truck surged at its strongest, the fuel pressure gauge fluttered at light speed. :notsure:

    If I lift, it goes steady back to 48, if I puch it, back to 48.
     
    jberry813, Jan 3, 2013
    #95
  16. Jan 3, 2013 at 11:48 PM
    #96
    jberry813

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    jberry813 [OP] Professional Fluffer Moderator

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    I put feelers out both in NorCal and Reno BS threads. :pout:

    2004, 60k miles.
     
    jberry813, Jan 3, 2013
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  17. Jan 3, 2013 at 11:58 PM
    #97
    Blackdawg

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    Blackdawg Dr. Frankenstein

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    But 42psi should still be totally fine..
     
    Blackdawg, Jan 3, 2013
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  18. Jan 4, 2013 at 12:27 AM
    #98
    SCSPerformance

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    Try swapping in a good known working MAF. If the symptoms are still there then it's time to do a compression test. If this past then do a leakdown test.
     
    SCSPerformance, Jan 4, 2013
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  19. Jan 4, 2013 at 5:28 AM
    #99
    disc0monkey

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    disc0monkey All right. I believe ya. But my Tommy Gun don't!

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    Is your voltage at the ECM and at the pump steady during this?
     
    disc0monkey, Jan 4, 2013
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  20. Jan 4, 2013 at 6:03 AM
    #100
    BamaToy1997

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    Correct, 1st gen Tacos don't have MAP sensors, but Second gens do, and the majority of all cars and trucks have them including Toyota. It is actually less common for a vehicle to NOT have a MAP sensor. Map sensors are located in different areas, but always behind the throttle plates, as that is where manifold pressure is located.

    The bolded text above is some cause for concern. High fuel pressure is not always a good thing. Anything that is above spec will cause a rich condition (even if just slightly) which can cause abnormal operation of the engine. This can be stuttering, surge, as well as possible exhaust odor being excessive.

    Your fuel pressure gauge fluttering at surge is for SURE telling you something there. The things that can cause fuel pressure to fluctuate like that are:

    1. manifold vacuum (due to leaks, or valve problems)
    2. pressure regulator
    3. fuel pump
    4. fuel injector
    So you are on the right track now. One test to perform would be the exact same test drive you just did, but disconnect and plug the vacuum line to the pressure regulator. Observe the gauge and see if the fluttering is still there. Yes, you will be running at the higher pressures, but this would eliminate manifold vacuum problems as a cause.
     
    BamaToy1997, Jan 4, 2013
    #100
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