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Thread: LNF tune won't keep high boost

  1. #1
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    LNF tune won't keep high boost

    I tuned a 2007 Saturn Sky Redline for a friend. The car baselined 238rwhp/257rwtq. The boost was right at 14.5psi. The (attached) tuned combo made 286rwhp/334rwtq. Boost was in the 23psi range. The mixture during the dyno session was quite a bit leaner than commanded so the MAF was tweaked in the upper flow range. The car ran flawlessly on the street, pegging the boost gauge at 23psi. Later, the friend reported that the car was only putting out 11-13psi. They were also getting a P2261 code. Can somebody please check out the attached tune and see if I made any rookie mistakes? I would appreciate it if you could tell me if this is something tune related or if the car could be experiencing some kind of mechanical issue. Thanks!
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  2. #2
    Senior Tuner cobaltssoverbooster's Avatar
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    i think you missed dissabling the boost tests under the engine diagnostic tab.
    i can look further tomorrw morning

  3. #3
    After a quick once over, I don't see anything in the tune that would cause that particular code to come up. Has he checked for any vacuum/boost leaks and made sure his BPV is in good working order? There was a TSB out for the vacuum tank leaking and throwing this code.

    I will look over the tune a bit more this afternoon for you.
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  4. #4
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    Quote Originally Posted by cobaltssoverbooster View Post
    i think you missed dissabling the boost tests under the engine diagnostic tab.
    i can look further tomorrw morning
    Any help is appreciated thank you.

    Quote Originally Posted by Gremlin85 View Post
    After a quick once over, I don't see anything in the tune that would cause that particular code to come up. Has he checked for any vacuum/boost leaks and made sure his BPV is in good working order? There was a TSB out for the vacuum tank leaking and throwing this code.

    I will look over the tune a bit more this afternoon for you.
    I could really use another set of eyes on this. The car held the high boost settings for about half an hour of driving, then all it will do now is 11-13psi. I will install the stock tune and see if any codes still come on. It's worth noting that I had to add about 11% to the MAF table to get my commanded AFR in line with the actual AFR. Could that additional MAF airflow coupled with the high boost make the air load out of range? The air load went to 270% and the grams/cyl went to 1.80. Seems pretty high.

  5. #5
    Senior Tuner cobaltssoverbooster's Avatar
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    exceeding max load limit on the axis is not a problem. g/cyl is a cap for lsj because the ve table ends at a set axis value. the lnf makes calculations internally to support over axis values.

  6. #6
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    Found the problem. My buddy's wastegate was missing the boost reference line. It had slipped off because the dealer forgot to slide the spring clamp back over the fitting. The high boost blew it off. Runs great now. We even did some boost by gear tweaks. Thanks for looking.