Doing TBI swap to 69 GMC

[67ChevNut]

I am trying to install a 1987 TBI engine in my 69 swb GMC. I have a complete 1987 suburban that I am parting out to do this swap. I have the complete engine, with sensors, computer, etc. I also have a 1989 blazer gas tank that I am planning to use, I have an original 96 suburban fuel pump that I will be placing in the gas tank.

I want to keep the original inside cab wiring harness, my questions are:

How do I make the computer work if I am using the original 69 GMC interior wiring, and the headlight wiring as well?

Is there a special aftermarket wiring kit for this application?

What kind of wiring will I have to do?

I will probably be installing the gas plumbing from the suburban as well, want to make this easy. What other things should I consider for this swap?

Thanks a bunch for the replies.

[hugger6933]

You have chosen the closest thing you can get to bolt on injection for your truck. Now all of the mounts and stuff are no problem and what you should do is find somebody that wires in the LS type motors and have them rework your harness or look it up on the net you may could do it yourself so that it is a three or four wire tie in to your harness. You shouldn't need much more than a keyed hot and a constant hot to feed the computer then your up and going. It will make a great clean swap. Good luck. Jim

[Chevypoor]

Jim is correct. We have an aftermarket painless TBI harness that is designed to be wired independently of the host vehicles harness. Should be able to locate an 87 wiring diagram and remove the extra wires and make your own stand alone harness. Then just hook up the hot wires to a fused feed from the battery. As a matter of fact we do not need our harness... pm me if interested.

[dirtyjim]

go on over to http://www.gearhead-efi.com/Fuel-Injection/forum.php all of the wiring diagrams are there along with lots of other info.
I was going to do a tbi swap on my 67 but I,ve decided to go a different route using a 411 ls pcm with a 2002 express van tune so I can use the ls pcm with a vortec distributor, have trans control and a much faster flashable pcm than can handle big cams

[Katrina/10]

If you carefully remove the 87 harness and mark every connector, you should be able to reuse it. It's nearly a stand alone harness already. I located the ECM on the side of my heater box inside the truck, and the wires were the right length.

[Greenlee]

This thread has a lot of info.

http://67-72chevytrucks.com/vboard/s...d.php?t=352321

[Orange Crate]

The guys over here have a separate fuel injection section with tons of infos. (Why don't we have a FI section?)

http://coloradok5.com/forums/forumdisplay.php?f=81

[MARKDTN]

Originally Posted by Katrina/10

If you carefully remove the 87 harness and mark every connector, you should be able to reuse it. It's nearly a stand alone harness already. I located the ECM on the side of my heater box inside the truck, and the wires were the right length.

I agree. Don't think you want a '96 fuel pump, that will be a Vortec not a TBI. My advice is buy a new fuel pump and be done with it. The '87 Suburban one should be fine.

[Acorn]

I did a TBI swap on my '70 and it is pretty easy. The harness I had was messed up and I did not have the time or the patience to rework it so I bought a reworked stand alone harness from warrperformancellc on e bay. It was under $200 and well worth it. The seller was more than helpful in answering my questions. Everything on the harness was labeled and it came with instructions. You only need to run power to a few wires and a couple grounds and your good to go. Very easy!
As far as the fuel pump, the '96 will be higher pressure but i think its a better pump. As long as the regulator in your tbi unit is ok and you have a proper size return fuel line, you should be ok. But you really don't need more pressure if the engine is stock. Either way I would recommend buying a NEW pump.

[67ChevNut]

Appreciate the replies.

I will defenitely buy a new pump, want to make as painlessas possible.

Still confused about the wiring though, I'll check those links and see if I can figure it out. Is there a thread with detailed pictures showing this wiring conversion? Sure like to see one.

This is a pic of the ecm:

[MARKDTN]

I would buy a manual for the donor vehicle so you have an accurate wiring diagram. You will find on an '87 that the TBI harness is pretty self-contained. It goes to all the engine components, through the firewall, and to the computer. If memory serves, the only wires left over are SES, hot, ground, ignition, and maybe some sensors. Can't remember about fuel pump, but I think that is in the harness too. It's about as simple as a fuel injection harness can be. The later ones with 4L60E transmissions have a lot more stuff in the harness.

[dirtyjim]

once you start disassembling the harness to clean it up it will start to make better sense.
you will want to get a weather pack disassembly tool, you will also more than likely have a few connectors that are damaged or have got brittle over time and will break when you try to remove them. I wouldn't bother trying to get the new connectors from the junk yard, a lot of them are available at the local auto parts stores or at http://www.clipsandfasteners.com/Soc...tors_s/265.htm

[Orange Crate]

Here is a wiring diagram for 1227747.

[67ChevNut]

Ok, bought a warrperformancellc tbi wire harness in ebay. I am trying to install it, but I need a switched 12v source conection inside the cab. I have no power in my truck since battery is not conected and still need to conect other wires. I am unable to use a test probe to find one. Can somebody tell where exactly I can get one from the fuse box?

[67ChevNut]

A better pic of the fuse box

[MARKDTN]

http://67-72chevytrucks.com/vboard/s...d.php?t=547020

A good photo of each fuse slot. See upper right side "Ignition unfused" Use a female spade connector and you are good to go.

[67ChevNut]

Thanks for the reply, that info is going to help me a lot! Hope to have it running pretty soon.

[Acorn]

I'm in the process of moving and I can't find my old instruction but I think there is a wire or two that need power in both the start and run position. Just an FYI