i am just about ready to convert my LG4 to TPI and i have NO EXPERIENCE at all "repinning harnesses" ive searched the internet cause i thought i could have my harness repinned by sending it out and having it done professionally but it seems as though no one offers this service anymore... i was wondering if there was anyone in my area or in the tri state(pa,ny,nj) that would be willing to help me out with this, i just about have everything i need just waiting on a few parts and such but i should have the whole thing ready in approximately 2 weeks, if anyone knows of a place that will repin my harness if i ship it out or if you can do it for me please hook me up with that info thank you

 

https://www.thirdgen.org/forums/diy-...nning-how.html
Its not hard, just need to know what goes where.
Plan everything out and you'll see where you'll need to add/remove wires.

 

so what do i matchup the colors? i have NO idea even where to start... should i install all the hardware, ie intake manifold etc and then start pluggin everything in till i get to the computer and dash?

 

You'll need to locate schematics for the existing wiring and from the donor car and compare.
If you are removing the LG4 harness there will be a few connections for the Instrument Panel (I/P connector) that you will probably want to use.
These can be spliced in or the existing wiring reused when you cut out the rest.
Matching colors alone will not work. Some colors may match up but I wouldn't count on that when going to different setups.
You should do the homework to be sure everything will work when you get done. Autozone has a bunch of schematics and would be a good place to start if you don't already have them.
Do you have a high pressure fuel pump?
LG4 runs on low pressure around 5 psi, TPI needs 43 psi.

 

This might help a little. http://www.chevythunder.com/

 

yes i am getting a new fuel pump and the hard lines from a tpi car... im just really pessimistic about being able to do this the more i hear the harder it sounds. im sure i can install all the hardware its just the wirring that has me worried as ive never attempted anything like this

 

Your best bet is to get a complete TPI harness. Easiest would be for one that matches the year of your car. This also means that the TPI set up would be MAF. You can get a harness from a '90 - '92 TPI vehicle. This will use a MAP sensor, not MAF.

The difference is that it won't just 'plug into' the '87 vehicle. You will need to make some changes.

You mentioned that your '87 is an LG4 5.7l. An LG4 engine is the 305 (5.0l) set up with a computer controlled carb (CCC).

The reason to get a complete TPI harness is because the LG4 ECM uses edge card connectors. Where the TPI ECMs use pin style connectors. It isn't just a re-pinning, but a cut and splice to use the current harness. And, there isn't enough wires in it to convert from a CCC harness to an EFI harness anyway.

The other item is which year TPI set up are you going to use? There are differences in connectors along with a cold start injector.

RBob.

 

xxx

 

87 5.7L LG4 means i swapped the long block, the intake and carb are the same as well as the distributor and computer. the tpi setup i have is an 1988 MAFS system from an Iroc im wondering if the wiring harness from 1988 is so much different from a 1987 and can i make due with the one i have or do i have to use an 1987 harness. also my car is an auto and the harness comes from a 5sp iroc, do i need a harness and comp from an auto or can i just switch out the pcm?? and from what i gather it sounds as if i am just replacing the harness because i have the whole new harness, so i take out my old harness and replace with the new one and im done??? how do i get my gauges to work or can/should i just get the gauge cluster and gauge harness from a donor car??? where will the repinning be done??? im real confused right now lol

 

ttt

 

still no help?