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.

[rfmaster]

Originally Posted by BigrobDog

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.

@BigRobDog

Take a look at your CS-130 plug.



In most case it will have only two wires populated - Large red and smaller gauge brown. The red goes to terminal labeled 'S' and brown goes to 'L'. Terminal letters are hard to see but they are part of plug body!!!

Disconnect plug from OE '72 external voltage regulator shown in the photo below...



extend wire from CS-130 plug 'L' terminal to reach terminal #4 of the OE '72 external voltage regulator.

//RF

[rfmaster]

Oh wow - it is nice to have a power lift -> CAT!

With VSS you have a small problem. The 90 burban uses electronic speedometer, while '72 truck is a classic mechanical unit.



To solve this you'll need to find a mechanical speedometer gear cable unit from an earlier 700R4 and add an inline 2000 ppm VSS unit from JTR.com. For example AC-Delco 25512339. But first you need to figure out which speedometer gears to use before ordering.



Also complicating conversion is that you have a 4x4 burban and VSS may have been installed in a transfer case (I simply do not know).

//RF

[BigrobDog]

Originally Posted by rfmaster

Oh wow - it is nice to have a power lift -> CAT!

With VSS you have a small problem. The 90 burban uses electronic speedometer, while '72 truck is a classic mechanical unit.



To solve this you'll need to find a mechanical speedometer gear cable unit from an earlier 700R4 and add an inline 2000 ppm VSS unit from JTR.com. For example AC-Delco 25512339. But first you need to figure out which speedometer gears to use before ordering.



Also complicating conversion is that you have a 4x4 burban and VSS may have been installed in a transfer case (I simply do not know).

//RF

i think it is on the back of the transfer case on the out put of yoke.but i dont think u can add a mechanical cable .

[BigrobDog]

Originally Posted by BigrobDog

i think it is on the back of the transfer case on the out put of yoke.but i dont think u can add a mechanical cable .

Oh wow - it is nice to have a power lift -> CAT! ,, I just read that , funny , ya im a diesel mechanic and have the shop to my self on the weekend. , but my question is , I have read all 39 pages and have learned alot about tbi , my truck halls ass down the road . one problem im having is when I smash the pedal it get no response, have to ease in to it . then it gets on it , is that because of the drac , i have the 4x4 . and when reading all the post sounds like on the 4x4 model that the drac is used to run the speedometer . and another question is my brake switch is not hooked up to my harness what wire is that on my tbi harness, i love this tread , thanks for all the help.

[rfmaster]

CS-130 Alternator swap info

http://67-72chevytrucks.com/vboard/s...d.php?t=567472

[jasons]

I wired B8 for the AC signal into the dark green lead to the compressor. Now with the compressor pluged in there is continuity between B8 and B1 which is a 12v battery wire hooked to a junction block and also between B8 and B3 the black/red wire to the distributor plug. Is this normal?
It makes me think the AC would always be engaged.
The compressor that is on the engine now is locked up and will be replaced, could this be the cause?

[rfmaster]

Originally Posted by jasons

I wired B8 for the AC signal into the dark green lead to the compressor. Now with the compressor pluged in there is continuity between B8 and B1 which is a 12v battery wire hooked to a junction block and also between B8 and B3 the black/red wire to the distributor plug. Is this normal?
It makes me think the AC would always be engaged.
The compressor that is on the engine now is locked up and will be replaced, could this be the cause?

B8 is AC signal ON input signal to ECM. So unless AC -heater selector switch is set in AC operate position and evaporator pressure control switch is closed there should not be +12 V at B8.



It is an input signal to ECM indicating that compressor clutch has been engaged. Move AC control selector and see if this voltage goes away when move AC to heater position (no AC).

//RF

[rfmaster]

OK - yes, you'll need to get IAC replaced.

When you go through the IAC reset the plunger should extend fully and close off air bypass passage. You should hear a clicking noise while ALDL pins A & B are tied together and IAC is plugged into the harness. SES light should be on as well. Your assumption about how IAC operates are correct.

Lets address IAC operation first before moving any further. I assume that EGR valve is installed, but vacuum hose is disconnected???

The other items to be aware of - make sure that all harness ground connections are tied to their respective grounds. There are two main ones - in front by the thermostat housing and one in the back of the passenger cylinder head. Loose grounds will drive ECM nuts!!!

//RF

[jasons]

Originally Posted by rfmaster

OK - yes, you'll need to get IAC replaced.

When you go through the IAC reset the plunger should extend fully and close off air bypass passage. You should hear a clicking noise while ALDL pins A & B are tied together and IAC is plugged into the harness. SES light should be on as well. Your assumption about how IAC operates are correct.

Lets address IAC operation first before moving any further. I assume that EGR valve is installed, but vacuum hose is disconnected???

The other items to be aware of - make sure that all harness ground connections are tied to their respective grounds. There are two main ones - in front by the thermostat housing and one in the back of the passenger cylinder head. Loose grounds will drive ECM nuts!!!

//RF

The IAC did click when A&B pins were jumpered, I'm just not sure the plunger extended completely, the new IAC valve will be here in a couple hours.

The EGR valve is installed and the vacuum hose is connected. Should it be disconnected for this?

I will double check grounds at the ecm plug.

[rfmaster]

Originally Posted by jasons

The IAC did click when A&B pins were jumpered, I'm just not sure the plunger extended completely, the new IAC valve will be here in a couple hours.

The EGR valve is installed and the vacuum hose is connected. Should it be disconnected for this?

I will double check grounds at the ecm plug.

BY disconnecting EGR you'll make sure that EGR is not active at idle. This is just a precaution.

There are no grounds at ECM - there are two multi pin plugs that plug into dual row connectors. The grounds that I referring are harness grounds - 3/8 ID lugs in the engine bay.

//RF

[jasons]

I have ground at the following plugs.

A12- blk/wht- System ground
B3- blk/red- Distributor plug
B10-orange/blk- park neutral switch wire
D1- brn/wht- system ground
D6- Tan- O2 sensor ground to engine

[jasons]

Installed the new IAC valve and did the reset procedure. Now it idles at 2,500rpm.

I'm at a loss. It's hard to search for a vacuum leak when you don't want to let the motor run.

Just a thought, but could too much fuel pressure cause this?

The fuel pump is rated at 29 GPH @ 12 PSI which should be right. Would a blocked return line boost the pressure? I ran into that on an 87 Dodge pickup once, but the increased fuel pressure caused it to shut down after a couple seconds, not run fast.

Any ideas? I appreciate it.

[jasons]

Having run out of ideas and remembering late last night that a friends 87 body swap project was in one of my storage units I swaped throttle bodys. It now idles like it should. I must have gotten something messed up when I put the kit in my throttle body. I'll have to go throught it again.

Thanks for the help RF.

[BigrobDog]

all i got left is my drac to wire up . has any body got info on were to wire each wire to, 90 suburban 350

[Jonboy]

Just a quick fuel question, for a swap into an older vehicle. I am getting ready to help a friend do a TBI swap into a '74 Blazer, but it does not have a return line. What is the best way to do one? Should I use rubber line going back to the tank, (and does the return need to be FI rated?), or does it need to be hard line. I am planning on using an inline fuel pump and using the original feed line. Also, where are you guys putting the fuel filter when doing an inline pump?

[rfmaster]

Originally Posted by Jonboy

Just a quick fuel question, for a swap into an older vehicle. I am getting ready to help a friend do a TBI swap into a '74 Blazer, but it does not have a return line. What is the best way to do one? Should I use rubber line going back to the tank, (and does the return need to be FI rated?), or does it need to be hard line. I am planning on using an inline fuel pump and using the original feed line. Also, where are you guys putting the fuel filter when doing an inline pump?

1) You'll have to become a plumber and install a new 3/8" supply line - for example SUM-G2538 aluminum fuel line which is easy to work with. Use your old line as return. Do not use rubber line - it will increase pressure drop and will deteriorate over time. As a minimum supply must be 3/8" and return 5/16". Return is a low pressure, but it still carries fuel. When plumbing vehicle for EFI keep safety and long term maintenance in mind!!!

2) If you have a baffled tank - use in tank fuel pump. In case of conventional tank use largest fuel filter you can find before inline FP inlet port. Large fuel filter will act as a mini surge tank and prevent fuel starvation when fuel sock gets uncovered. It is not a perfect solution, but it is as close as you can get away with without building a full surge tank system and lift pump.

//RF

[Jonboy]

Wow. I would have thought that the feed line would have been 3/8 already. Guess that's what I get for trying to engineer a TBI swap from 250 miles away. Thanks for the heads up.

[rfmaster]

Originally Posted by Jonboy

Wow. I would have thought that the feed line would have been 3/8 already. Guess that's what I get for trying to engineer a TBI swap from 250 miles away. Thanks for the heads up.

It probably is a 3/8" line, but after 40 years of service I would be leery to subject OE fuel line to high pressure. Fuel fires kinda ruin your day! In carb operation the fuel is sucked from the gas tank by the engine mounted fuel pump. In the EFI system fuel pump is working against FPR mounted in the TB, hence between fuel pump outlet and TB FPR fuel system is pressurized. Leaks are not good since today's gasoline is a nasty concoction of Gasoline and ethanol and other 'poop' that I do not care to remember.

//RF

[iceship]

So what is the least about of componits you need for the engine to fire up. ....
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[rfmaster]

The thread has been quiet for a while! For those who are looking to upgrade TBI harness from JY pulled rat nest or contemplating clean carb to TBI swap Northern Autoparts has a special on Painless EFI TBI swap harness #60101 this week:

http://www.northernautoparts.com/Pro...ProductId=1468

//RF

[iceship]

Any of you guys put a. obd-11 in your truck. .. I'm taken engine and trans out my old 93 roadmaster wagon..
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[rfmaster]

Originally Posted by iceship

Any of you guys put a. obd-11 in your truck. .. I'm taken engine and trans out my old 93 roadmaster wagon..
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The engine and trany from 93 roadmaster should be equipped with TBI which is OBD-1. Last year for TBI in B-body before cast iron LT-1 was introduced in B-body in 94 model year. OBD-II vehicles were mandated by 1996 model year. Between 1993 and 96 GM had some car platforms that were equipped with hybrid OBD - the so called OBD 1.5

What is your question regarding TBI - OBD-1 (yes we run it in our trucks) ??

[iceship]

Obd-1 plug does it just run to the pcm or its it more to it than that. .
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[rfmaster]

Originally Posted by iceship

Obd-1 plug does it just run to the pcm or its it more to it than that. .
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1) PCM = power train controller found in late model OBD-1, 2 systems and is used to control EFI and transmission shifting (4L60E, 4L80E). Prior to 92 ECM only controlled EFI and TC lockup.

2) OBD-1 plug was wired to a number other modules - anti lock computer, Air pump solenoid. In early OBD-1 prior to 92 model year plug provided interface to ECM