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Multiple misfires after rebuild ** FIXED **

Discussion in '1st Gen Tundras (2000-2006)' started by Brynden29, Jul 16, 2022.

  1. Sep 15, 2022 at 7:15 PM
    #571
    shifty`

    shifty` Is the Gila Copter a love machine?

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    upload_2022-9-15_22-15-14.jpg
     
  2. Sep 15, 2022 at 7:55 PM
    #572
    NickB_01TRD

    NickB_01TRD You don't need less cars, just more driveway.

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    @Brynden29 I'd say roll with the coil packs but get the proper denso sparkplugs from rockauto or a local parts store.
     
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  3. Sep 15, 2022 at 8:22 PM
    #573
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    Which plugs should I get?
     
  4. Sep 15, 2022 at 8:26 PM
    #574
    NickB_01TRD

    NickB_01TRD You don't need less cars, just more driveway.

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    Denso K20R-U is what I got for my 01
    Link
     
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  5. Sep 16, 2022 at 4:59 AM
    #575
    shifty`

    shifty` Is the Gila Copter a love machine?

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    And only for reference sake to confirm what Nick is saying, this is taken directly from the '02 owner's manual that's here on the forum. You've got two options. Gapping is below the recommended plugs.

    upload_2022-9-16_7-59-9.jpg
     
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  6. Sep 24, 2022 at 9:27 AM
    #576
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    Here are the drivers side plugs (misfire side):
    3FC5CD90-AC88-4801-9D42-D25C3D223E86.jpg

    Here are the passenger side plugs (working side):
    F1BD78BB-3C41-4F5E-AC5F-797DFB610CE4.jpg

    They all look good to me.
     
  7. Sep 24, 2022 at 9:38 AM
    #577
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    I just did a cold compression test:

    1 - 210
    2 - 210
    3 - 204
    4 - 195
    5 - 198
    6 - 215
    7 - 215
    8 - 210
     
  8. Sep 24, 2022 at 10:27 AM
    #578
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    I swapped the ECU back to my stock one. When it first started I was only getting misfires on 1 & 3. Once the STFT went negative it started missing on all the cylinders. I hooked a vacuum gauge to the intake manifold:

    910E2F5B-6F49-4169-9315-60C7015BBABB.jpg

    I don’t know how much vacuum I should have at idle. Here is a video of the gauge:

    https://youtube.com/shorts/1zkrxs6OrFU?feature=share

    Thoughts?
     
  9. Sep 24, 2022 at 10:55 AM
    #579
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    I also hooked up the exhaust back pressure tester to the drivers side upstream o2 port. It was right about 0 but when I reved it up and let off it actually went negative. So I assume it is very free flowing? Should there be some back pressure at idle? If there isn’t could that mean and exhaust leak at the manifold? I know that I tightened the nuts down but they were the original nuts and I don’t know if I should have replaced them. Thoughts on that too? Thanks guys.
     
  10. Sep 24, 2022 at 10:57 AM
    #580
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    One other thing, I just took it for a drive and the STFT were very low:

    3F6AF7D5-6129-4D0E-B8AF-B49EB1C3C3C7.jpg

    I hadn’t driven it enough to calculate a LTFT when I took this picture.

    what could be causing the ECU to pull so much fuel?
     
  11. Sep 26, 2022 at 5:33 AM
    #581
    shifty`

    shifty` Is the Gila Copter a love machine?

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    Vacuum is definitely one thing I'd brought up - mostly because the 'happens at idle, not at load' is a typical sign of vacuum leak.

    Other members have mentioned potential for exhaust leak causing this, and it makes logical sense it could be the cause.

    IIRC, you mentioned using the gaskets that JBA supplied with the headers, right? If it were me, I'd have gone with new hardware, but usually it's because exhaust hardware ends up being rusty as hell/degraded by the time I'm swapping headers, and I just want fresh bolts. :rofl:

    Either it believes it's burning lean (i.e. O2 is reading lean on that bank when actually not, or pulling outside oxygen after combustion, but before pre-cat O2?) or it believes it's pulling in way more air than it actually is (bad MAF, bad TPS?) would be the two big ones I can think of.
     
  12. Sep 26, 2022 at 7:08 AM
    #582
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    Thanks for the replies. I am sure you are tired of this, as am I.

    I used the JBA gaskets, but the nuts and bolts are stock that I reused. The bolts all stayed in when I took the stock exhaust manifolds off. I reused the nuts, but I am thinking maybe I need to get new ones.

    I did replace the maf sensor (I bought a hitachi one from Amazon for $71.66) and I assume the TPS sensor lives in the throttle body, which is brand new also.

    If there was a maf issues why would only one bank be affected? The intake manifold feeds both banks equally. That doesn’t make a lot of sense to me.
     
  13. Sep 26, 2022 at 7:39 AM
    #583
    shifty`

    shifty` Is the Gila Copter a love machine?

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    At this point, I'd just like to see some success, wouldn't you? :rofl: (that's rhetorical)

    I assume you'd want to stick with the JBA because they're made for their LT headers and don't necessarily match stock. But I really don't know. Bolts are easy enough to swap. Pop out and swap one at a time, torque to spec, then (I like to) go back over with two random passes, usually in a 1-3-2-4 style pattern to confirm torque. FSM may say something different, this is just how I've always done it since I was a teenager and never had issues.

    Exactly. Neither would TPS. I was just tossing out the two cases I could figure OTOH that would explain it.
     
  14. Sep 26, 2022 at 2:55 PM
    #584
    dbittle

    dbittle Middle Age Member

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    The plugs definitely don't look like the mixture is too rich on bank 1, so to me that puts the spotlight firmly on something being jacked up in the O2 sensor system on that side. It could be something like a bad ground connection, not just a bad sensor itself.
     
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  15. Sep 26, 2022 at 8:17 PM
    #585
    Tundra2

    Tundra2 Zoinked

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    This makes me think!!! Do you have any reputable shops that do harness testing?

    I had a ground issue on my truck that I simply couldn't find... I was missing a ground on one of the upstream 02 sensors that kept making my trucks fuel system go into Open Loop. I took it to a shop that tested the entirety of the wiring harness, and found that there was a ground disconnected somewhere in the circuit of that oxygen sensor. I swapped ECUs, changed sensors, and just about everything before I broke down, and plopped the truck off at the shop. They had it fixed in a few days.

    Just a thought for you. Might be worth pursuing.

    Heres a link.
    https://www.tundras.com/threads/crackhead-resurrection.94083/page-57#post-2641393
     
  16. Sep 26, 2022 at 8:37 PM
    #586
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    I will say, the wiring harness I am using is the one I bought from an online junk yard. I assume that it is good, all the connectors look way better than my old broken ones.
     
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  17. Oct 1, 2022 at 10:32 AM
    #587
    fighthedude

    fighthedude New Member

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    Any progress?
     
  18. Oct 2, 2022 at 6:04 PM
    #588
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    I haven’t had a chance to mess with it. I am waiting on new exhaust manifold nuts from Toyota. Then I will be putting them on.
     
  19. Oct 2, 2022 at 8:47 PM
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    fighthedude

    fighthedude New Member

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    Copy. Hoping that is the trick for you bud.
     
  20. Oct 2, 2022 at 9:23 PM
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    Rodtheviking

    Rodtheviking New Member

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    2017 Limited Crew TRD, Ironman Pros with JBA uppers. Prinsu rack. RSI, RCI sliders

    Regular old NGK V powers

    BKR6EYA
     
  21. Oct 5, 2022 at 5:14 PM
    #591
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    I finally got the exhaust manifold nuts. They say they are locking. They appear to be able to lock against the threads. I know that my current ones don’t lock anymore. Maybe they are coming loose and causing the leak. I’m hoping to swap them out this weekend.
     
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  22. Oct 5, 2022 at 5:24 PM
    #592
    shifty`

    shifty` Is the Gila Copter a love machine?

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    If this whole issue ends up being nuts ... that'll be seriously nuts.

    But will also be a very potent lesson for others, down the road, and a learning experience for a LOT of us.

    Fingers crossed ....
     
  23. Oct 7, 2022 at 4:26 AM
    #593
    dbittle

    dbittle Middle Age Member

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    Thinking more….. it thinks it’s too rich so the ECU pulls fuel. It’s not, so it starts to misfire. Bring rich drives the O2 sensor voltage high, so the voltage on the sensor output wire is either too high or the ground reference is messed up. If the new exhaust nuts don’t fix it, recommend OP back probe the o2 sensor wires and see what they are really saying.
     
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  24. Oct 15, 2022 at 10:12 AM
    #594
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    Welp, the nuts didn’t fix it. I guess I will be calling around next week to find who can back probe my o2.
     
  25. Oct 15, 2022 at 10:26 AM
    #595
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    Here is some fresh o2 data. It appears that I can see the voltage of the o2 sensors. I don’t know what it means.

    https://youtu.be/1EWRYR9aPeA
     
  26. Oct 17, 2022 at 4:27 AM
    #596
    dbittle

    dbittle Middle Age Member

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    That’s good that you have the voltages there, so no need to probe anything. The voltages range from 0 (lean) to 1 volt (rich). They both seemed to be oscillating back and forth, but with that huge long term fuel trim subtraction on bank 1. Could you swap the sensors again, reset the ECU and see see where the trims settle out after that?
     
  27. Oct 17, 2022 at 4:58 AM
    #597
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    Swap the sensors from the left to the right? The problem is, I had to extend the passenger side o2 to make it reach. So I can’t just swap them over.
     
  28. Oct 17, 2022 at 7:44 PM
    #598
    dbittle

    dbittle Middle Age Member

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    Well, crud. O2 sensors are expensive, so its tough to just say to make a blind replacement. If you're open to lengthening the cable on the drivers side one (which is the one giving the questionable readings anyway), you could swap them.

    From the video you posted, it looked like both sensors were oscillating from low to high, but the drivers side fuel trim was pegged out lean. That sensor should have been staying low all the time I would think. My theory is the misfires are due to the lean condition caused by the fuel trim.

    I'm wanting to see if a known good sensor (the one on your passenger side) would generate that same fuel trim number if you swapped them over, reset the computer and drove for a few days. If the good sensor acts the same as the other one, the next move is probably to check the ground wires. Best of luck brother. If there's any justice in the world, you'll get it picked apart. You've definitely earned it!
     
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  29. Oct 18, 2022 at 5:55 AM
    #599
    Brynden29

    Brynden29 [OP] 2002 Tundra Limited

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    I totally get your thinking on this. It would be a good test. My struggle is, the truck misfires right after resetting the ECU and before the o2 sensor starts sending info. The more I think about it, it might be something mechanical. I probably need to pull the valve cover and check the cam positions.

    when I reset the ECU all the fuel trims are set to 0.4 (I think). And the truck still misfires at those fuel trims. It’s not as bad and it is just a couple cylinders. Maybe I’ll reset it and film the first start up on the scanner.
     
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  30. Oct 18, 2022 at 7:02 AM
    #600
    N84434

    N84434 In the Frozen Tundra

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    Considering the O2 sensor has lengthened wiring, and it's not in the factory position, would the added resistance or changed sensor location have any bearing on this conundrum? I know this was previously mentioned, but I just had to ask...:hattip:
     

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