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Anywhere ever put a vortec 350 fuel injected engine in your elky? I have a 78 elky wanting to put a 98 vortec 350 fuel injected over in it with the 4L60E tranny. and I have the entire donor vehicle it came out of. what all of the wire harness am I gonna need. what all of the harness am I going to need to delete from it. Any help is highly appreciated. Thanks in advance
 

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I don't think anyone has a complete 'wires to eliminate' list / schematic to make it a 'one size fits all'.
I'd highly suggest you just use the entire harness and don't plug in what you don't have. There is plenty of places to hide the 'extras' you don't need. he way the L31 Vortec computer was I think you will have it throwing codes and running in Alpha-N mode if you don't get feedback from all of the BS sensors it likes.

I'm definately no expert here, and not sure of anyone who may be when it comes to the L31 truck harness. But just offering an opinion based on what I have learned about the OBD1, Holley Cmmander EFI, and MSD LS harness w/ Delphi ECM. Without a programmer, you are better off keeping every 'original' sensor and the harness in tact.
 

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I have been contemplating this very subject for a while. If you want some professional help, look here: http://www.pcmforless.com/

It looks like they have tackled a few different swaps from efi systems to electronic transmissions.

On a different note, do a search about the fuel injection spider, it has known issues with carbon buildup and the problem has a solution.

-Jarod
 

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I recently started investigating something similar- upgrading my Vortec L31 TPI engine to the later version of the ECM. Thought it would be easy, but the more I studied, the harder it got. Bottom line for me was having to spend $500-$900 for a software program to get the tune right, on top of all the conversion costs. I know you can buy a "Mail Order" tune, but my experience with doing the TPI swap was that I have done at least 20 tunes so far, and counting. I would expect the same issues on a conversion, and I just can't justify spending the money on the software.

This would be a fun swap, but it is far from just a drop in. I would think really hard about this before jumping in, and make a very complete budget of the parts, etc you will need. Harness, programming and fuel delivery can run close to $2K pretty easily, and the Vortec injectors are known to be trouble spots.

For $100, you can buy a Vortec intake manifold that will accept all of your current carb, accessories, etc, and you will be up and running with a strong L31 350 pretty simply.
 

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There are some older threads here in the tpi/lt ls section.
You either convert the harness into a stand alone version, have it done,or a new harness. You will need unused items removed from computer .Check with places like Howell.
Personally, I think if you,re going to do an efi swap these days, the newer ls series is a better choice, even the cheaper 4.8 & 5.3 engines. Lots of info on ls1tech on these.
 

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Hey Keith, did you ever accomplish the update? I too have a 78 Elky and would like to put a 4.3L with MPFI from a 2003 or newer S10/Silverado. Contemplating many of the same issues you were facing, any nightmare/success stories would be helpful!
Thanks
 
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