Tbi swap build thread

[BigrobDog]

Originally Posted by rfmaster

@BigrobDog

OK - thanks for posting photographs - these help quiet a bit.

In Photo # 1
Your 1990 burban donor came equipped with CS-130 Alternator. This alternator has internal regulator. OE external '72 regulator that you have in Photo #2 will not be used. To adapt CS 130 to the '72 wiring is actually straight forward, but it will require a bit of DIY soldering. Are you up for it????

CS130 alternator is rated for 105AMPS maximum output and will deliver around 30 to 35Amps at idle. Which is plenty.

Look at the back of alternator. There, you should see BAT terminal and big fat red wire should be running between alternator BAT terminal and terminal block that is part of EFI harness - mounted on the passenger side firewall. I thinks there is one, but it is taped-up and not clearly visible. That wire should have been a part of '90 burban harness. From the firewall mounted terminal block there also should be a big red wire running to starter main terminal - its also should be a very thick red wire - 8AWG. Please take a close look and capture a photo of it in case if it is not connected. A fuel pump relay should be in close proximity to that firewall mounted terminal block.

Back to CS-130 alternator. There is a multi pin plug with several wires protruding from it.. Most often it is just a brown 16 AWG wire tied to 'L' terminal. This is a alternator light bulb wire. You can NOT connect this wire directly to the instrument alternator light. This connection can only be made if there is a series 150 to 300 OHM 1Watt resistor ( between alternator plug and instrument cluster alternator light). This is done by disconnecting external regulator plug from OE external regulator module and connecting brown wire from CS-130 'L' circuit with a series resistor to terminal 4 of the OE regulator plug - also brown wire. At least GM was consistent with their wire color schemes over decades! . Schematic below does not show this resistor, but it must be there.



Sometime, there is a larger gauge red wire tied to S terminal - this is a voltage sense line. This wire should be tied to a BAT terminal block on the firewall.

Photo #3
This is a tough one - this portion of the harness was connected to 90 burban main feed through block. The wires protruding maybe useless - anti lock computer, windshield wiper motor, temperature sensor, etc. It is best to remove split loom and peel off electrical tape and determine where these wires went.

VSS - this is a long discussion in itself. Do you have 700R4 from donor or you still have THM-350/400???

P/N switch - some DIY is involved but can be easily implemented. Search this thread for schematic.

//RF

your showing a 4 prong plug i only have 2 prong plug brown / and orange.. so brown to 4 plug and and orange to back of + alternator. is this right , nothing at all will be hook to external 72 regulator.is power wire to dash were the light goes , or is that voltage out put.