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I trying to get a better understanding of exactly what needs to happen on the wiring side of my upcoming LS swap in my 98 Tahoe 4x4 and I have a question for those of you that have repinned your OEM harness for use with the 411 PCM.
did you reuse the wiring from the OEM injector connector and just add individual coil pack connectors to it or did you remove all those wire from the harness and start new ones from the 411 PCM?
Just to avoid cutting and splicing, I removed the coil wiring and the injector witing from the donor truck harness and loomed them into my trucks factory harness. They were plenty long and now I dont have spliced wires. Just how I did it but would work just fine either way.
so where did all the wires go from your OEM harness that once went to that big injector plug on the Vortec engine? Can they all be removed from the harness or do I need some or all of them for other things now?
Also, does anyone have any feedback on what happens with the EVO sensor on the PS pump? My truck has this steering assist sensor and Im not sure where this would now tie in to the 411 PCM
I just removed them completely. But if your not adding any new wires from the PCM you just need to splice into the original injector wiring which will work out just the same. You'll just be using those wires for the injectors nothing else.
The power steering plug can just be left unplugged if your going with the LS donor ps pump. Nothing will happen at all. I did just that and glad I don't have that variable power steering anymore
I cut off the big injector plug and had my injector wiring already inline on the motor and soldered the old to the new. I got lost with Lextechs diagram and ended up running a lot of the LS plugs and wires directly to the PCM. I got overwhelmed and I will definitely do it differently next time.
link to said diagram?
You'll have to pm lextech for his witing file
Quote:
Originally Posted by capricefrk013
what would you do differently? Would you use Lextechs diagram or use the GEN 3 harness and PCM along with the stock PCM?
I would start from scratch and made my own harness. If I had the time, which I didnt because my truck is my DD, I wouldve gutted the entire harness from the engine bay and grafted everything together as if it was supposed to be. In a way, Lextechs diagram would make that happen but its the details that I care about and I am not happy with the way mine turned out but again it is my DD and I couldnt be out of it any longer. I deal with 12 volt wiring every day and I make damn sure I am perfect with my wiring everytime.Quote:
Originally Posted by BOTTLEDZ28
Good to know My truck is my DD too and I know exactly how you feel about the wiring needing to look perfect. I did exactly that with my camaro build. I ripped out the entire engine harness and tossed in in favor a stand alone hanress from FAST. I then grafted the needed circuits to it and away it went. It took a while but the end result was a very neat and uncluttered engine compartment AND the wiring was done correctly. It sucks when we try to mod our DDs because time ends up dictating the quality of our work sometimes.Quote:
Originally Posted by capricefrk013
Im still torn right now on what to do with the harness side of things. My brain is about to explode from reading this forum, gmt400 and lt1swap!! Just when I think I have a good grasp on what needs to happen and what parts I need, I find someones elses build thread and BAM, they did something different.
Thats exactly how I felt when researching mine. I just made sure I had all the parts I needed to mail order were on hand before starting and the rest of them I had delivered from the parts store while working on it.Quote:
Originally Posted by BOTTLEDZ28
You could use the wiring on the LS motor and just remove the unneeded wiring from the OBS engine harness and leave the trans harness alone and just pin them in to the 411. Splice the cruise wires in to the TAC module that will mount in the same location as the cruise. Repin the data wire from OBS PCM to LS PCM so the OBDII port still works.
When I did mine, I used Lextech, LT1swap and Alldata diagrams to make sure all was correct. The only think that was messed up with mine were the o2 sensor wiring. I am gonna go speed density on mine so I wont need them anymore.
Capricefrk, what issues did you have with your o2 wiring?
So Im undecided on which direction I want to go in with the wiring side of things.
Use OEM harness and modify it per Lextechs diagrams
Use the harness from the donor engine and modify it to run with the 411 PCM and keep the stock PCM on board to run gauges
decisions decisions
Well no matter what way you decide to go there is no reason what so ever to
Keep the original ecm. Just get the wiring file from Lextech and modify your harness. You can still take the time needed to make it look good and it will fit your engine bay the way it's suppose to. The 411 will run all gauges and all. No need to keep the old black box.
I MAY just modify a GEN3 harness to as long as I can get some detailed info on how to get the trans wired in to work with 4wd. I dont want the truck to be down for a prolonged period of time. If I can get a jump start on the wiring side of things while the engine is on the stand then I can continue to drive my truck until the last possible minute prior to the swap.
I managed to get a chopped up LS harness from a 2001 2wd truck along with the 0411 ECM. I havent dug into it yet to see what was cut out of it. What I want to know is if the my trucks OEM harness connectors for the engine are the same as the LS connectors. If all the connectors plug into the same sensors then I might just use the OEM harness and add in the injector wiring from the LS harness.
Not all of the plugs are the same. most are for the most part.