2004 silverado 4.3 to 5.3 swap. constant 12v to coils and fi no signal to coil packs

hello,

this is a NO START issue... i am new to hptuners but fairly proficient at tuning and the concepts involved. i did a 5.3 swap into a 2004 silverado that ran and drove but only had a 4.3 in it. i reused most of the 4.3 harness and just repinned certian sensors. i have 12v constant to ckp, cmp, and pcm. i have 12v constant to ignition coils pink wires. and i have good grounds at ignition coils black and brown wires. but no signal to the coils from the pcm. and i have verified the fuel pump comes on for 2seconds when key is cycled so i know the ckp and cmp are working as well.... it has to be something simple. is it a bad pcm? or something else? any help is appreciated. thank you for your time. mike in oklahoma

post script... i kept the 4.3 pcm and retuned it with hptuners so it now thinks its a stock 5.3, also took out the dbw in the dtc section since im using a dbc throttle body. i programmed out vats, egr, secondary 02's, and evap system.

anyone?

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Originally Posted by 71k3500

post script... i kept the 4.3 pcm and retuned it with hptuners so it now thinks its a stock 5.3, also took out the dbw in the dtc section since im using a dbc throttle body. i programmed out vats, egr, secondary 02's, and evap system.

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First and foremost, post a file. It's shooting in the dark without a file.
What does the line I placed in bold mean? Did you change the settings in the PCM or did you change the OS to match a 5.3 calibration?

how do i post a file here? i changed the settings in the pcm to 5.3 v8

Quote:

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Originally Posted by 71k3500

how do i post a file here? i changed the settings in the pcm to 5.3 v8

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Select "Go Advanced" on the reply and there is a button to upload a file.

Did you actually load a 5.3 calibration from somewhere or did you just change the engine size to 5.3? The latter won't work.

ok i did not load a 5.3 calibration. how do i go about doing that? i was told by hptuners that i could select the engine size and it would work.

I had the same problem before. You need to write a full 5.3 tune to it or do a segment swap from a 5.3.

I can't say because I can't see the calibration. The problem in your case is likely because the base calibration is from a V6 and the engine you swapped in is a V8. The base OS is different because of the physically different hardware (8 coil packs vs. 1 distributor). What will happen is 1 coil will fire and the other 7 will not (among other things) creating the no-start condition you describe.

Depending on your PCM, you may not have IAC drivers on the board. If you are trying to go drive by cable this won't allow the PCM to control the Idle Air Control valve.

thank you guys for enlightening me. how do i go about this segment swap or full tune?

To do a segment swap you need to be using the 2.25.x (beta) software. The option isn't available in the 2.24.x build.

What needs to happen is after a swap to a V8 base calibration is a "write entire" while the default option is "write calibration only." The difference is writing only the settings information within the calibration and writing the entire operating system and settings. You can add or remove features the second way depending on what changes have been made or are available.

Are you wiring a constant 12v to your sensors coils, inj's, etc? Those should be wired to a key on power circuit on those pink wires not constant power. Reason being once it starts up you wont be able to shut it off with the key if it is constant. Alt. will keep it running. You can do as above for a segment flash. Just changing the engine size in the drop down tab doesn't copy the full segment, you will have to download a V8 file from the repository unlock it, or upload the whole file. Since it's DBW I have had issues copying engine only segments rather than adding the whole file. The transmission settings are programmed to the v6 also. Better off in my opinion to just upload a whole base file and tune off from there. Hope that helps!

If you can find one, Use a Van calibration from the same year. It will be drive by cable application.