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Thread: Deleted vats, but still no spark or fuel?

  1. #1
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    Deleted vats, but still no spark or fuel?

    Hey all, Im having some issues, thinking that my computer isnt actually writing even though it says job complete. I went in and changed vats to none and deleted the EVAP stuff under engine Diagnostics. but when I try to start it theres no spark or injectors opening. I pull up the computer in the scanner and it shows 140 ish RPM while cranking. Also shows 12.5 timing advance but when you check the plugs there is no spark. I have 12v to the injectors and the coils (verified with power probe) I have all the other pink wires and orange wires twisted and taped together to a hot wire direct to the battery. I hot wired the fuel pump also. Vehicle is a 2004 5.3 trailblazer, motor and trans are still in the vehicle, I wanted to do a test fire with the Vats removed to make sure it still worked after I trimmed down the harness as per LT1swaps.com I drove this thing into the garage 4 days ago, now it wont run. any ideas ? any way to read the computer while its on the vehicle? when I try to read it the button isnt highlighted on the VCM Editor, but the Write button is

  2. #2
    Tuning Addict blindsquirrel's Avatar
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    Close the tune file and the 'read' button will come back. If a tune is open the only option is 'write'.

    Yes, do a new read from the PCM and save as a new file, see if the changes you think you're making are sticking.

    I'd start over with the stock file, change ONLY the VATS, do a 'write entire' (you have been doing 'write entire', right? it won't work if you do calibration only after a VATS change), cycle the key, close the tune file, do a fresh read and look at the file that comes OUT of the PCM to see if the changes survived the write.

  3. #3
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    thank you, Ill go try that. also I dont see the option for write entire. only write calibration and write vin-lock-vats or something of that nature, where is write entire?

  4. #4
    Tuning Addict blindsquirrel's Avatar
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    What version VCM Suite are you using? I don't have a Gen3 anything here to connect to to see what you're looking at. My Gen4 doesn't have the Rewrite VIN/Tunerlock/VATS option, only Write Entire, Write Calibration, & Do Not Write.

  5. #5
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    ok I tried that and it still didnt work. I pulled the tune back off and attached it and the Log of me trying to start it. it seems to me the tune worked, when I pulled it back off it said vats was disabled, see if you can see what Im missing trailblazeq2.hpt nostarttrail.hpl

  6. #6
    Tuning Addict blindsquirrel's Avatar
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    You changed a bunch of stuff all at once (hot-wiring all of whatever, VATS, EVAP, etc.) and now all of a sudden it doesn't run. Maybe put everything back to how it was when it did run, then change ONE thing at a time until it stops working?

  7. #7
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    Im using version 4.4.2, I cant really go back, Ive taken to much wiring out of the dash, and depinned the fusebox. I have successfully wired up a standalone for a 1zz, and done 2 8 valve trackers and a 16 valve tracker motors into samurais, with all factory dash and all functions working great. Ive had a couple little dumb things I missed on my other swaps, but nothing I wasnt able to chase down fairly quickly. Im confident that my current wiring, while temporary in execution, is correct, at least per the diagrams and diagrams Im going off of. basically on the engine harness there is a handful of pink wires and 2 orange wires that need to be connected and it will run. the Drive by wire system works fine, if i press the gas pedal the throttle body responds. Im not sure If I possibley have the wrong software or I somehow damaged my computer but Im about to pull my hair out. I really do appreciate you taking the time to try to help me
    Last edited by Creepycrawler; 05-16-2019 at 06:32 PM.

  8. #8
    Tuning Addict blindsquirrel's Avatar
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    What wiring changes have you made that require a VATS disable? In other words, what would it take to get back to where it should run with the bone-stock OEM tune file in it?

  9. #9
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    Complete removal of the bcm, removed wires from the underdash harness to remove the OBII connector. removed random wires from the underdash harness in preparation of extending wires to the new fuse box. completely depinned the fuse box and multiple connectors. there are no wires from the engine or ECU that go through the firewall any longer. finding diagrams and fixing/repinning would be a 3 to 4 day job, just to see if will run on the stock tune again, then i would undo what it just took me 4 days to do. Im pulling the motor and trans to put in my 67 chevy truck

  10. #10
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    did more testing today verified 12 volts at the Coils and Injectors, also have 12 and 5 volts at the MAF. Checked the coils with a test light, checking for the computer to ground them to fire them, no flash on the test light. moved up the wiring to the connector on the valve cover, still no injector pulse. inspected the wire all the way from the connector back to the computer, no issues found, looks to be in perfect shape. Im really thinking Im having computer issues, as it is reading the Crank position, showing 140 RPM while cranking but refusing to fire the coils. Thoughs?

  11. #11
    Tuning Addict blindsquirrel's Avatar
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    Why do you not have a 'write entire' option in the flash menu, instead of just the 'Rewrite VIN/Tunerlock/VATS'? Is that a Gen3 thing, do they not have that option now? They used to, according to the out-of-date help files. You need to post in the Gen3 section and find a P59 guy. My only suggestion at this point would be to go through everything in the Supported Channels list in the scanner and find all the relevant stuff - VATS status, injector pulse, whatever - I don't know what will be in your supported channels list, but there's bound to be a lot more than what you have in the log you posted above.

  12. #12
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    thats good advice, Ill make another log this weekend. I did find the write entire option, Im not sure why it wasnt a option the first time, or maybe I just missed it. I didnt know vats status was a option thats super helpful

  13. #13
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    Update, still no start, but I did check for vats with the scanner, it said passed. However I also decided to rewrite the original file I pulled off my computer back onto it and see what happened. Both files were "write entire" and both files where pulled back up in Editor to make sure that they wrote correctly. However when I hooked up the scanner running the original file it also says vats passed. which is impossible since its totally disconnected. I really think Im having problems with HP Tuners not actually changing anything in the computer. All my sensors are reading and showing movement when I try to start. It just isnt actually firing the coils or injectors.

  14. #14
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    Did you try disabling the starter diag in the system tab, general?

  15. #15
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    Check all your earths are present for the coils and injectors, it caught me out before !
    Gen3 L59/4L60E LS3 cast manifolds, Small Cam change, 2800 Convertor, MPVI, using MTX-L for wideband tuning

  16. #16
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    Check what else is under your OS tab, guaranteed it's this right here "starter fault checks"....put that to use, write entire and you may be good.

  17. #17
    Tuner in Training BADWOLF's Avatar
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    Try setting P1626 and P1631 to no error reported...

  18. #18
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    I am on the same boat, any update?