I posted about this a while back and received little help and now I am hoping that someone can really help me out...

My Camaro is originally a 1991 with a TBI 305 and a TH700R4... I have recently swapped in a T56 transmission and a GMPP 350... I would like to use TPI for my fuel delivery... I picked up a 1987 MAF TPI system out of an 87 GTA and the computer that goes with it... Unfortunately the wiring harness that went with this system was wrecked so I had to go to Ebay to get a harness...

The Harness I received was rough but with some new connectors it could work just fine... However, it is pretty apparent that I need to combine it with my original TBI harness to have a complete wiring harness (The TPI has all the engine management connectors, but nothing that goes into the fuse block, and it seems to be missing more)...

This is where my problem begins... I am not great with wiring and could use some help in how to combine the two harnesses (If this is in fact what I need to do)... I would consider a new wiring harness but I have heard bad things about Painless harnesses and don't know what to do...

If anyone can help me in any possible way it would be greatly appreciated... I would prefer to work with the TPI Harness I already have, but if there is a much better way to approach this situation I am all ears... If there is a good aftermarket harness I will definitely take that into consideration... Please help I have been working on this project for 2 years now and would like to once again be able to enjoy my thirdgen.

(FYI... I have already changed my fuel pump and installed all the TPI Components... I am currently only haveing problems with the wiring)

 

What exactly do you have questions about? I converted a 1987 Monte Carlo SS that had a computerized carb to a TPI equipped 406 with T56. I used a '830 computer and a friend of mine made a harness from a TBI equipped V6 early 80's G-body. As it turned out I had to nearly rewire the complete harness and in the process I learned tons of info... if I were to do it over I would build a harness from scratch.. if you want there are companies that sell complete harnesses like you want but I think if you go to chevythunder.com and look up the pin callouts you will quickly understand how simple it really is.
The main thing is to make the proper changes to the PROM such as the T56, etc.
Let me know how I could better help you and I will try to get you going in the right direction.
Good luck!

 

Ummm, what have you heard about painless??? I have a painless for my speed density setup cuz I had MAF. It fit just fine with no trouble at all and any questions I had were answered by their tech dept. I ripped out the old MAF harness and installed the new one. That took me the longest time. Everything else was easy. If you dont want to go through the trouble of splicing etc. then buy a harness.

 

I have used a painless harness on 2 different TPI swaps and am very pleased with them, you may or maynot have to add/extend/shorten wires to fit your application better.

First one was a standard length MAF harness which made locating the ecm a difficult process in a 79 3/4 ton silverado.

Second one was the extended (3feet) length MAF(which has now been repinned for SD) mounted in my 82 ElCamino.

The only complaint I had on them were how tight some of the zipties were on the harness(some actually chaffed the insulation a little! ) which was easily solved by cutting the ziptie off and putting another on not quite as tight.

 

There's a guy that posts on these boards and sell's harnesses on e-bay
His name is "S10wildside" if I recall correctly
From what I can tell,he does some quality work
Do a search in the classified section,for his username
Check him out
Later
Steve

 

Painless does make a good product (tho expensive) and nice thing is all the sensor connectors are new!
I extended my fuel pump and cooling fans so I could place them behind the headlights so you can do the same with the 'store bought' kind.

 

Thanks Steve,

I'm still working with the TPI harnesses (converting a few TBI to TPI right now). For a project such as the one in this thread, I always want to talk over the phone about the project before making a commitment. I always request payment after I finish a harness or do work on a harness. There are a few guys on this board who have contacted me about building/modifying harnesses, several have had me work on their projects.

 

I did a writeup a few months back on repinning the TBI harness to TPI. It can be done on a saturday afternoon with a 6 pack.

Do a search on the TPI and TBI boards.

It's easy.

-- Joe

 

The only thing that caught me by surprise was the way the A/C compressor is wired. If you don't look closely at the diagrams, you can easily miss the wiring difference between the TPI and TBI harnesses. Otherwise it's pretty easy...just time consuming.

 

Well yeah btu that doesn't have much to do with engine management, other than A/C switch engagement for idle rise.

-- Joe

 

Since he is running a 91 car and there may possibly be smog cop problems (location was blank) I would think converting to a MAP system instead of a MAF system would be a smarter move...... Not to mention have more horsepower potential....... Oh darn, I guess I did mention it!

 

The best thing to do is make a sketch of all the wires you will need and then go back and compare to where you are.
Then the problems become less and you have a positive direction to go.
If you were to just put one of the harnesses in and begin picking away at probles I think the problems will begin to multiply from confusion.
I remade a new harness from scratch because of the confusion it caused me. Although a lot more work, the end result will be trouble free
A full diagram will also keep you focused on what you need. The extra connections you will be removing always come back as "what did I forget to hook this up to??"
Extra power wires can also cause shorts if left uninsulated and sensors not all grounding to common points can cause problems with readings as well.
The actual cost of making a harness from scratch was about the same as buying one. The best benifit was that all my emmisions stuff can now be used or not (my choice). Most aftermarket setups do not have them included.
I have a diagram for my 90-92 SD setup of my 86 Monte that can be used as a starting point.
Check it against your wiring (mine is colored and probably different)
Hope this helps.
JP

Edit: Found the thread where my other info was posted, my help.
https://www.thirdgen.org/techbb2/sho...hreadid=242358

 

I am planning on deleting the A/C and A.I.R. systems from my car... would this cause any problems?

 

The A/C will not cause any troubles (just don't wire the input to the ECM) the idle goes up by a programmed amount when its turned on.
The AIR stuff also has an effect on the O2 mixture when on and can cause you some trouble but not serious (I don't think so anyway) Should be handled though.
If you are burning your own chip, both can be programmed out and then there is no problem at all.
Thats the best thing to do.
I wired all mine up and just turn them off when I don't want them.
I like the flexibility to use it or not. I have emmisions testing here and "might" need to use it. My first check will be at the end of the month. I really don't have much concern, It's tuned pretty good now .
Hope this helps ya some more.
JP