Wiring harness question

[89Suburban]

No reason to change the harness just to install the 350. Just swap the ecM, as there are different chips for the 350 and 305.
The oil pressure sender on the 350 should be behind and to the drivers side of the distributor, tapped in with the oil pressure switch for the fuel pump.

 

[Hoodbj]

Thanks, I will check out the oil sending unit tomorrow. As for the harness I agree, in sticking with what I have and just altering what I need. I have to pick up some shrink tubing and solder tomorrow. Thanks again fellows for the help! I really like the forum, very helpful.

 

[Hoodbj]

Transmission, starter driveshaft and crossmember in tonight after work. Installing a tranny solo is rough work. I had to see saw the transmission on 2x4s to be able to get it on jack and then balance it on the jack while trying to move it and jack it up to align at the same time, but it is done. Hoping to tie up all loose ends tomorrow, wiring, battery, fuel lines etc. hopefully have it puring by tomorrow or Sunday. Still have to check the oil sending unit and replace computer but getting close.

 

[HotRodPC]

Transmission, starter driveshaft and crossmember in tonight after work. Installing a tranny solo is rough work. I had to see saw the transmission on 2x4s to be able to get it on jack and then balance it on the jack while trying to move it and jack it up to align at the same time, but it is done. Hoping to tie up all loose ends tomorrow, wiring, battery, fuel lines etc. hopefully have it puring by tomorrow or Sunday. Still have to check the oil sending unit and replace computer but getting close.

It just takes practice brutha. I've put in many many transmissions by myself. Many times didn't even use a jack since it hindered the install. Of course, that might have something to do with having my first back surgery at age 30 too.

 

[MrMarty51]

88-89-90 Burbs had the Harness run to the left side of the firewall and to the right of the brake booster. One big grommett that the wires passed through.
Those would be the easiest to install into an older than 87 Square Body pickumup.
The 88 and newer pickups has a flat long harness under the H/VAC box and is a real pain to deal with.

 

[Hoodbj]

Ok ran into a couple of wiring issues. The alternator in the 350 has two wires that run into the harnes that are brown and pink with a black stripe. The 305 had one black wire Amin the harness and one orange with a eye to bolt to alternator. Also on the tbi on the front passenger side of the tbi there is a sensor if some sort with a completely different plug. Had to change the plug on the temp sensor also, geeze a lot of differences for a few years difference. Any help is appreciated!

 

[89Suburban]

It just takes practice brutha. I've put in many many transmissions by myself. Many times didn't even use a jack since it hindered the install. Of course, that might have something to do with having my first back surgery at age 30 too.

I used to lay under the truck, put the trans on my chest and bench press that fugger into place. That was nothing compared to those damned cast iron transfer case installs. They used to really piss me off trying to get it into place, heavy, awkward shaped bastards.

 

[89Suburban]

Ok ran into a couple of wiring issues. The alternator in the 350 has two wires that run into the harness that are brown and pink with a black stripe. The 305 had one black wire Amin the harness and one orange with a eye to bolt to alternator. Also on the tbi on the front passenger side of the tbi there is a sensor if some sort with a completely different plug. Had to change the plug on the temp sensor also, geeze a lot of differences for a few years difference. Any help is appreciated!

The sensor on the in the front of the intake manifold on the pass side of the thermostat housing is the temp sensor for the computer/TBI. Let me get you some diagrams for the '90 so you can reference and mod what you need to. BRB....

 

[89Suburban]

The black wire on the current alt plug, does it have a red stripe? If it is it should be going to the junction block.

The brown wire on the '90 alt plug goes to the instrument cluster. Why I don't know. For the Batt warning light maybe?


I am really confused about the colors you are reporting. Basically the small plug on the alternator is a trigger and the big wire on the stud goes to the junction block and in some cases a 2nd wire on the same stud goes directly to the pos terminal on the battery.

The pink/black wire should be a "ign on" switch power source to energize the alternator.

 

[89Suburban]

You must be registered for see images

You must be registered for see images

You must be registered for see images

You must be registered for see images

You must be registered for see images

You must be registered for see images

free pic

 

[Hoodbj]

Thanks for the help. The big black wire with a red stripe is hooked up. The two prong plug is what's throwing me on how to desire. The 87 alternator only had the one brown wire in the harness but coming out of the same connector was an orange wire about 4 inches long with a ring terminal that bolted to the stud with the battery wire if I remember correctly. The 91 alternator has two wires in the harness one brown and one link with a black stripe. I'm assuming brown to brown but not sure if I should loop the pink with black stripe like the orange wire was.

 

[Hoodbj]

And sorry for the confusion, the connector that doesn't match up is actually on the tbi itself, I will look over the wiring diagrams and see if I can figure it out. Worse comes to worse I should be able to switch throttle bodies.

 

[89Suburban]

And sorry for the confusion, the connector that doesn't match up is actually on the tbi itself.....

Which connector would that be exactly?

 

[Hoodbj]

Not sure it's purpose. It is actually part of the throttle body on the front passenger side. The old tbi had a flat 3 prong connected and the new one has a more square connecter. Both connectors are 3 wire but the wires are different colors.

 

[kleedus]

the 87 uses the old style plug on the firewall and the 91 uses the newer small style plug will not interchange

it would be easier to keep the 87 harness they both should be tbi

I was talking about the plug under the steering colmn 87 and 88 where tbi and used the same older style plug 89 to 91 used the newer style plug

so the under hood harness does not interchange