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383 starts and dies

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Old Feb 10, 2013 | 04:25 PM
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Default 383 starts and dies

ok normally i would say it needs a crank re learn from the safe tune but if i start it and rap the throttle she will rev.

this is my issue it fires and dies. wont idle. i have 52psi of fuel pressure. all 8 cylinders fire and it sounds amazing. but i have a 09 map sensor and i havent changed the plug on my harness so its still unpluged. is this why she wont idle and dies?
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Old Feb 10, 2013 | 04:46 PM
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Do you have a base tune in there for a 383 sized engine? It probably won't idle if you don't have it set up for the cylinder size, injector size and that MAF, among other things. If you have HP tuners, I can send you something or you can pull something off the repository. Otherwise, you'll need someone to tune it for you (the safer method).
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Old Feb 10, 2013 | 04:52 PM
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wheatley sent me a safe tune for it for the engine so i should be okay.
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Old Feb 10, 2013 | 05:02 PM
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I would try and hook up that MAF, although without it, it should run OK in default if the VE or idle airflow numbers are close. The problem might be that the numbers are off and it's running lean or rich. You will most likely need someone to tune it in person. Is that your plan?
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Old Feb 10, 2013 | 05:06 PM
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yeah i was hoping to drive it onto the flat bed and haul it off to the dyno. i dont hear any vacuum leaks from the lsxrt so im almost positive its tune related. but i have no way of checking.
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Old Feb 10, 2013 | 05:21 PM
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Hopefully you can get it on the trailer while it's running like that. Congrats on finally getting her fired up. I know it's been a long road for you.
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Old Feb 10, 2013 | 05:26 PM
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you think i may be having the LSXRT issues others are having? i really hope i am not but i really want to check everything i can. if it is not a tune issue i dont want to pay the dyno shop to fix something i missed.
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Old Feb 10, 2013 | 05:35 PM
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The computer needs either the MAP or MAF to run. If you have both unplugged it will fire and die right away.

The MAP is used in the VE table. So without it, that table is void. If it doesn't have the MAF, there isn't another airflow table to reference for fueling.
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Old Feb 10, 2013 | 05:41 PM
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maf is plugged in
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Old Feb 10, 2013 | 05:41 PM
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i have no idea if its working or not but its plugged in
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