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Thread: SOIT & EOIT Stock Motor

  1. #1
    Senior Tuner TheMechanic's Avatar
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    Question SOIT & EOIT Stock Motor

    Have a E92A, ECM, GM SIDI 2017 Tahoe 5.3 stock vehicle. Had a long term mis fires from lack of maintenance in my opinion. Melted the cats. Cats got hollowed out and I was going to be doing a trans (6L80e) tune and some VERY minor spark timing, PE, and a some DTC stuff obviously. Anyways they are complaining of the idle fuel smell. No kidding right? Have done many Gen 3 and Gen 4 EOIT adjustments for this will GREAT success but Gen 5? Yikes. Not even sure where to start. Not looking for a miracle just a reduction in the smell or where to start. Cats here in Kalifornia are double to triple the cost of any other state to purchase and they are stamped. If you have aftermarkets without the stamps you won't pass the smog and no company will mail these from out of state. Any help will be greatly appreciated.


    JAMES 2017 TAHOE E92A COMPLETE STOCK TUNE.hpt

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    Senior Tuner 04silverado6.0's Avatar
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    You can try this and see how it goes. Should be spraying much closer to tdc.
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  3. #3
    Senior Tuner TheMechanic's Avatar
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    Quote Originally Posted by 04silverado6.0 View Post
    You can try this and see how it goes. Should be spraying much closer to tdc.
    Thank you. I will give it a go. Vehicle should be here on Friday. I'll let you know after a test drive.

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    No amount of SOI adjustments will do away with the smell when you guy the cats.
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  5. #5
    E85 will clean up the smell better than fudging with SOI.

  6. #6
    Senior Tuner 04silverado6.0's Avatar
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    Any updates?

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    I was gonna say… you have no cats, it’s gonna stink like it’s 1974. Maybe try to get some used cats?

  8. #8
    Senior Tuner Ben Charles's Avatar
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    I get sick of hearing these big cam/ no cat setups complain about smell… it’s part of it

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  9. #9
    Senior Tuner edcmat-l1's Avatar
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    Quote Originally Posted by TheMechanic View Post
    Have a E92A, ECM, GM SIDI 2017 Tahoe 5.3 stock vehicle. Had a long term mis fires from lack of maintenance in my opinion. Melted the cats. Cats got hollowed out and I was going to be doing a trans (6L80e) tune and some VERY minor spark timing, PE, and a some DTC stuff obviously. Anyways they are complaining of the idle fuel smell. No kidding right? Have done many Gen 3 and Gen 4 EOIT adjustments for this will GREAT success but Gen 5? Yikes. Not even sure where to start. Not looking for a miracle just a reduction in the smell or where to start. Cats here in Kalifornia are double to triple the cost of any other state to purchase and they are stamped. If you have aftermarkets without the stamps you won't pass the smog and no company will mail these from out of state. Any help will be greatly appreciated.


    JAMES 2017 TAHOE E92A COMPLETE STOCK TUNE.hpt
    I'm not sure I get it. If you have NO cats, how are you going to pass emissions in Komifornia? I get that you need OE, but it sounds like you're trying to justify not having cats because they're expensive and then you mention the aftermarkets not passing?

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  10. #10
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    Quote Originally Posted by edcmat-l1 View Post
    I'm not sure I get it. If you have NO cats, how are you going to pass emissions in Komifornia? I get that you need OE, but it sounds like you're trying to justify not having cats because they're expensive and then you mention the aftermarkets not passing?
    It seems like he wants to try and solve it with a tune that adjusts SOI/EOI to reduce the smell and since the shell of the OEM cats are in place, it would hypothetically pass. But we all know the Catalyst Test will be set to fail or not ready and flashing the ECU won't help because California now does plug in emissions where they read if the ECU was altered. And no movement of the SOI is going to reduce the smell without cats. That trick is only minimally useful on big cam stuff.

    Sounds like the answer is to drive to a neighboring state and have cats installed. Truck owner chose to live in California, now deal with the ridiculous government laws and prices.
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  11. #11
    Senior Tuner edcmat-l1's Avatar
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    Ah, totally overlooked the "gutted" cats and was assuming they were removed.

    I agree, it would pass the visual but not the monitor check or the sniffer.

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  12. #12
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    It doesn't make any sense to take cats off. I've seen 1-2 rwhp on 500 rwhp NA builds. less than 10 rwhp on some big supercharged builds. The exhaust tone is better, no stink, no hassle

    I understand the cost.. but at a certain point you are spending more trying to make it work.
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  13. #13
    Senior Tuner edcmat-l1's Avatar
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    ^^^ Agree. I've put cats on, and recommended other people put cats on older, swap cars that really can get away with not having them.

    When you take your wife out in your 200K C1 or C2 LS swapped Corvette and she gets out smelling like fumes, well, enough of that shit. We need to fix it or she's not going out on cruise night.

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  14. #14
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    Now lets talk about open element valve cover breathers and the smell that sticks to your clothes/hair. lol
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    Quote Originally Posted by Alvin View Post
    Now lets talk about open element valve cover breathers and the smell that sticks to your clothes/hair. lol

    No, No, No How about all of the oil vapor coming out from under the hood or the very unlucky few that actually caught on fire because of the oil dripping onto the manifolds. I have swap customer send photo's for these reasons. They're a must go on gen V's if still using any of the factory breather configuration. I've even gone as far as having some running blow through setups route the breather hoses from the crankcases to catch can"s" and then the blower or turbo inlets just like factory diesel setups after leaving. Customers are happier for it as the vapor is no longer there and getting on everything. Just may require more maf cleanings is all.
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