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Need help diagnosing vct timing issues

Discussion in '3rd Gen - 2007 - 2017' started by Keepinitoldskool, Oct 25, 2020.

  1. 07navi

    07navi Full Access Members

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    I would wait until you get the cat issues taken care of before everyone starts speculating on everything here.
     
  2. Keepinitoldskool

    Keepinitoldskool Member

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    I'd rather get the engine running 100% first because I'm pretty sure that is why the cat melted in the first place. I'm gonna put a new 02 on there and start recording more PIDs until I find what is signaling these cams to retard at idle
     
  3. 07navi

    07navi Full Access Members

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    I would address the cat problems first. I doubt if one phaser advancing wrong is going to affect them for a long time if at all. People are putting those stupid wedges in them to lock them up solid and they have no effect on the cats.
     
  4. max78

    max78 Full Access Members

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    The rear o2 sensors do not adjust the computer. the only thing a gutted cat will do is fail emissions due to CEL, its a go/no-go gauge.

    Your computer relies on the front O2 sensors to make adjustments.

    really odd about your timing going out of whack. Comparing it to my phasers your look to be at a different angle. Your matches what I have seen in the youtube videos and others though, so I have no idea. .



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    Last edited: Oct 27, 2020
  5. max78

    max78 Full Access Members

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    Completely ignore my dumb post above. I didn't set the timing in that shot so of course its not going to look right. :Boo:


    If it runs fine until warm it sounds like there is a sensor issue somewhere. While cold it should be operating in closed loop mode ignoring the O2 sensors, only after the engine is up to temp does it switch over to open loop mode, which then rely on the O2 sensors for fuel trims. At least that how they used to operate. Monitor your O2 sensor data to see what is happening.

    I would pull your Bank 2 Sensor 1 (closest to the header) and inspect it for damage, maybe something happened when you were clearing the clogged cat.
     
  6. Keepinitoldskool

    Keepinitoldskool Member

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    After some more testing and data logging, I'm convinced there is something on the driver's side that is bleeding oil pressure. After the engine runs perfectly for about 30 minutes and I come to a stop, bank 2 goes advanced and stays there until the engine is shut down or put in neutral and revved. Since I put a new melling 340hv in it I doubt oil flow is the problem, and it's only on bank 2, which supposedly is the first to get the oil flow, and bank 1 has 0 issues, and swapping cam sensors made 0 difference. I'm going to try a thicker oil to see if my theory is correct. Maf, tps, fuel pressure, upstream 02 all look correct.
     
  7. 07navi

    07navi Full Access Members

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    Both phasers should always retard with higher RPM'S, right? I doubt if thicker oil will do anything, and I am wondering if one of the phasers is malfunctioning.
     
  8. 07navi

    07navi Full Access Members

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    delete
     
  9. Keepinitoldskool

    Keepinitoldskool Member

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    Bank 1 retards normally, bank 2 doesn't until enine is revved or shut down, leading me to suspect something on that side is bleeding pressure. A thicker oil is a "cheap" way to test this theory.
     
  10. 07navi

    07navi Full Access Members

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    If it was bleeding that much pressure the passenger side wouldn't work right since it gets oil last. Try 40 weight but I don't think it will change anything. With that good oil pump in there the driver side phaser should have more chance of working right than the pass side. Let us know what the thicker oil did.
     

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