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Thread: Jet Boat Tune, again.

  1. #21
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    Quote Originally Posted by Nodnarb View Post
    Check the tune repository. There's a couple 5.3's with camshafts you could steal info from.

    Bump up your Base Running Airflow, MAF transfer and VE table and learn how to use the scanner. You can get it done.
    Yeah man, I've been using the heck out of that scanner. Grabbing other scans out there and watching them run, looking at the numbers. It's all slowly starting to turn from Greek to English. LOL

    I've found a few tunes in the repository but it seems like most are on turbo cars.

  2. #22
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    This one is a 5.3 with a cam slightly smaller than yours.
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  3. #23
    Senior Tuner Russ K's Avatar
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    Do you have the flex fuel injectors? Because that is a flex fuel tune, and the injectors are 30% larger than on a none flex fuel engine. So that will cause +30% fuel trims.

    Also a bad Maf will cause +fuel trims.

    Russ Kemp

  4. #24
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    Quote Originally Posted by Russ K View Post
    Do you have the flex fuel injectors? Because that is a flex fuel tune, and the injectors are 30% larger than on a none flex fuel engine. So that will cause +30% fuel trims.

    Also a bad Maf will cause +fuel trims.

    Russ Kemp
    Yes, they are flex fuel injectors. A friend of mine asked me about the MAF also. It's a junkyard MAF from a 2001 I think, maybe a 2000. I was thinking of getting a new one. I just needed the junk yard one as a core.

    Man, I really appreciate all this help guys.

  5. #25
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    Ok, took the VE table Nodnarb posted up and added 3 across the board, raised the MAF thing to 6,000, disabled the STFT's and bumped up the idle air to the in gear setting for out of gear. When these boats are in the water and the engine is running the pump is always loaded so I try to set as much stuff to "in gear" as possible.

    We'll see how it lake tests tonight after work. Wednesday night is jet boat night at our local lake so if there is ever an issue it's easy to get a tow back to the ramp.
    Last edited by blazeracer; 05-09-2012 at 10:29 AM.

  6. #26
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    Quote Originally Posted by blazeracer View Post
    .....disabled the STFT's
    Yea I wouldn't do that. It's the effect, not the cause.

  7. #27
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    Well, I'm gonna remove the effect for a few and keep watch on O2's and KR to see what happens. Worst case it blows up and I go get another for $330.... LOL

  8. #28
    Senior Tuner Russ K's Avatar
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    Leave the STFT's enabled (closed loop). Then to rule out a bad Maf, set the Maf Fail Frequency to O. And make sure that a P0103 code sets. That engine should at least run ok with a stock VE table.

    Russ Kemp

  9. #29
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    Any chance you have pics of your monster? I wanna' see an LSX boat!

    Good luck on figuring out your issue, by the way.
    Matt

  10. #30
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    You're right. It didn't run at all with the STFT's turned off. I turned them back on and ran better than is has so far, but it still sucks. Here's a scan from it. I'll try setting the MAf fail to zero tomorrow and take it for a drive and scan again.

    Here's a pic from the test fit. The CAI with the MAF is not on here. I'll get another tomorrow.
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  11. #31
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    your o2 sensors seem to be either pegged at lean or rich...

  12. #32
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    Quote Originally Posted by MikeyZ View Post
    your o2 sensors seem to be either pegged at lean or rich...
    I noticed that too. Pegged at one or the other. Gotta be another failure going on here.

  13. #33
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    Ok, backed it down the boat ramp and ran for about 5 minutes. Didn't get a P0103 code, but got a P0101 instead.

  14. #34
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    Here's a questions though. I'm searching and can't find it. Why do I lose all DBW control when the MAF is disconnected? The pedal will be completely dead till it's reconnected and the key turned off and back on. It does this whether the MAF is unplugged or if the CAI is off and the MAF still plugged in. I both cases the DBW shuts off completely if the MAF is not in front of it breathing. Will it matter if the MAF is off of a 2000 5.3 DBC and I have a 2002 5.3 DBW?

    Apparently I'm not the only one who has seen this.

    http://www.monodax.com/forums/tunerc...-less-dbw.html
    Last edited by blazeracer; 05-10-2012 at 12:07 PM.

  15. #35
    Senior Tuner Russ K's Avatar
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    Don't just unplug the Maf cuz the IAT sensor will default to -39*F. Just set the Maf fail freq to 0, and set the P0103 to no mil and uncheck the SES box. Leave the Maf plugged in.

    Russ Kemp

  16. #36
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    OK, I'll try that. BUT, I have a 2000 GMC with the 5.3. Just took the MAF off the boat and put it on the truck and it ran just fine. Did a scan, all looks well. The STFT will add a little fuel, the O2's will pick it up and cut the STFT's back down. It's like they do a little back and forth dance. The boat is not doing that. The STFT's will peg in the boat and stay that way with the O2's pegged also. Like the O2's aren't trimming down the STFT's.

  17. #37
    Senior Tuner Russ K's Avatar
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    Then you probably don't have flex fuel injectors. Get the number off them & google the number to find out.

    Russ Kemp

  18. #38
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    Quote Originally Posted by Russ K View Post
    Then you probably don't have flex fuel injectors. Get the number off them & google the number to find out.

    Russ Kemp
    Can do... The motor was a complete pull. The only things I didn't get with the motor was the pedal, the TAC and the MAF. Should the kPa on the MAP be as high as it is? It's sitting around 70-75 at idle.

  19. #39
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    Quote Originally Posted by Russ K View Post
    Then you probably don't have flex fuel injectors. Get the number off them & google the number to find out.

    Russ Kemp
    Bingo Russ!! The injectors are 25317628, non flex fuel injectors. Someone here said I have a flex fuel tune. How do I get this corrected?

    I wonder how that happened? I personally went to the wrecking yard, pointed out the Tahoe and told the guy to give me that engine, and they put the complete unit in the back of my short wide.
    Last edited by blazeracer; 05-10-2012 at 01:46 PM.

  20. #40
    Senior Tuner Russ K's Avatar
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    You need to find a 5.3 T engine tune, every 2002 Tahoe/Yukon 5.3 in the repository has a Z engine code which is a flex fuel. I would just open up a 5.3 T engine pick up truck and copy over the injector tables to your tune.

    And I was the one that said you have a flex fuel tune.

    Russ Kemp