Need help merging together wirings of 1990 5.7/350 in cabin with 1998 5.7 vortec eng

[Aksl]

Hi everyone,

Some of you are already familiar with my project, to be short it is a Chevy Silverado 1990 step side k1500 5.7/350, with all top end from 1998 5.7/350 vortec (Heads, manifold, MPFI spider injectors, pro comp cam 08-467-8, 0411 PCM from moates with road runner emulator, 4L60E transmission).

So i had long road taken with this project, changing on the way this and that. And lately after installing 4L60E transmission, had trouble of PCM recognizing it, and since i had a scrap wiring, that was cut here and there before i even got it, and had no cruise control working plus to all, and the under hood fuse box cut out, i decided that i get a new used wiring of a 1998 Tahoe, and start merging it together with my in cabin wiring from scrap, so i did get the new used wiring, all completely whole, with no wires cut or damaged with the fuse box, taken of a car to be cut and sold by parts at junk yard.

So i know there are many swaps of engines in trucks like mine to L31 engine, and swaps exactly like mine, but i have searched all of the net, and can`t find any info on merging the two wirings together, the incabit with underhood, via the bulkhead connector C100 and C200 connectors to merge with the 1998 wiring, to have everything functioning, the A/С, Cruise Control, etc...

If anyone has some info, it would be grate, cause for now i have some pinouts for these connectors, but not sure that they are the correct year. And the 1990 schematics are so difficult to follow.

Thanks in advance folks.

[dave w]

Merging wire harness is very challenging!

I've worked with several L31 conversions on the 1986 - 1995 pickups, re-using all the original TBI harness.

For 1986 - 1992 an upgrade to the 16197427 PCM is required.

The next step is to convert the 16197427 computer to MPFI, which mostly consists of rewiring to the L31 injector pod wiring to the TBI injector wiring.

The next wiring modification is to add the 4L60E wiring harness.

Then install a custom PROM chip, and tune as required.

dave w

[Aksl]

Hello Dave, thank you for feedback.
As you have noticed, i have repined the L31 vortec engine (underhood) wiring for 0411 PCM, that can control and the vortec injectors and the 4l60e.

You are absolutly right it is challanging, i am braking my brain for this setup, still thinking should i keep the underhood fusebox, i know folks choose to cut it out, to make the wiring more simple and neat. The L31 underhood with 0411, can work by it self, controling everything and the 4L60E, with out the incabin wiring, like most make a bench for L31.
But want to merge everything to work together. I wonder why there is still no rewiring schem or file out in the net yet for this setup, like Lextech has made for the 0411 repining file, it's realy a mistery..

[dave w]

Planning is a good thing when re-wiring.

The option to delete the '0411 fuse block is a solid plan.

The list of old TBI wiring that can be reused:
Fuel Pump Relay wiring.
Battery +
Battery -
Ignition On / Start
Old TBI fuel injector wiring
Old TBI coil power
ALDL Wiring (reconfigured)
Add HO2S wiring
Add MAF Wiring

dave w

[Aksl]

Planning is a good thing when re-wiring.

The option to delete the '0411 fuse block is a solid plan.

The list of old TBI wiring that can be reused:
Fuel Pump Relay wiring.
Battery +
Battery -
Ignition On / Start
Old TBI fuel injector wiring
Old TBI coil power
ALDL Wiring (reconfigured)
Add HO2S wiring
Add MAF Wiring

dave w

Thank you Dave.

[Aksl]

Ok as i called the thread i have done some homework)), i have made some connector wiring pinout charts for two main connectors i have to merge: The C100 Bulkhead connector & C200 passenger side firewall connector (in 1990 k1500 its called C273 connector, in 1996-1999 C200).

I have obtained a new used untouched wiring of a 1998 Tahoe with fuse-box and everything uncut/untouched, and started looking on how to merge my in cabin wiring with new under-hood, i as well have my old under-hood wiring. And what confuses me is this, the old under-hood wiring was looped with the in cabin wiring, because everything was going from engine to cluster and modules behind cluster & behind the dash and then to the ECM with corrected by modules or cluster signals i guess, not direct. Where as in 1998 vortec the under-hood wiring is hooked up directly to the PCM. So for me to hook up my cluster and all the modules inside the cabin as well as under-hood modules that my old wiring goes to like ABS & Cruise control, how should i pair the wirings Sensors -> new PCM - > Incabin, and if one wire has to go to both, just split it? Or does it have to be sensors -> cluster and in cabin staff -> New PCM.
For example my VSS signal used to go from trans case to C100 Bulkhead -> Cluster -> C273 passenger side -> ECM. I can live that as it is and get the VSS signal to my New PCM from C273 connector, but that will bee a hell of a loop of wires around the cabin, or i can just have the VSS signal go directly to the PCM From the trans case, and then have separately signals go from pcm to speedo etc..

As well i`m a bit confused on how to merge these connectors C100 & C200/C273 together correctly, totally different wires in old vs new C100 & C200/C273 connectors, only a few are coming and going to from to same place in one-another...

Hope my tables will help someone and ease their job.

If someone could suggest me a way out with my headache, i would appreciate, a psychologist will do but only if he has experience in swapping L31 into 1990 L05 truck.