This thread is to help swappers finish up their install. It isnt complete yet, early year pinouts are still needed







That is a 98 Fbody LS1 CTS. If you go to a common parts store asking for a CTS, you will most likely get a 2 pin version correct for pretty much ALL GM engines except 98. Ask for the temp sender

 

Pocket, I don't know what most of us would do without you when it comes to the electrical end of the LSx swaps. Subscribing in anticipation of my swap this spring.

 

Pocket you are a genius. I have a question doing the 96 LT1 swap. I have the 3rd gen pretty good but the LT1 part is confusing for some reason. I prep'd my third gen harness but where on the LT1 harness do I start to plug in my wires, near the pcm or......? My harness for the Lt1 came with the fuse box attached but no fuses and two relays attached to it and a black (which seem to be a battery ground cable) battery cable thats mounted inside of the fuse box. I ordered a shop manual for the 96 LT1 which will hopefully go in to detail but i need to know where the red( positive battery cable) comes from for the fuse box. is that black cable the power or ground? your diagram is in its simpliest form but in the chart(side by side) from the c100 to the LT1 is that what wires match up. I know I asked alot but I want to do a compiled tutorial for the non technical people who just dug in with no skill or know how.....like me. I have learned so much from these message boards and TGO so thanks to you fine folks here.

 

Please read this thread
https://www.thirdgen.org/forums/ltx-...rt-finish.html

Specific excerpt:
In other words, I cant help you with the fuse block because I simply do not know. I do know the stock 3rd gen fuseblock/relay center is more than capable of controlling your LT1 and is already in place, functioning

It sounds like you got a B-body harness as the 4th gen Fbody harness has a separate fuse block. Regardless, a fuseblock will never be a source of heavy grounds, esp for a battery cable. IIRC that cable went to the alt output

The connection chart shows what needs to be spliced where to the swap harness. It doesnt go into detail about the pieces that still need to be plugged in, like the brake sensor, starter solenoid wire etc. These are still critical, but are not directly spliced into the new harness

Go over the LS1 harness thread. Its not identical, but the procedure is the same: marking, disassembly, mockup, lengthening, etc.
Use this diagram to help get you started


I havent made one for the 96-97 cars yet, they added a few connectors

 

Another excellent and informative that just got added to the sticky

 

I personally just used this bit of genius tonight with my wiring.

 

A link to this thread has been added to the LS1 swap sticky.

Thanks for sharing all your good wiring info with us.

 

Some more diagrams

Engine schematics
LS1


0411 SBC


Trans wiring





Several people race their swap and need a kill sw, here is what I use in my racecar

 

Full braided fuel systems with PNs. Rail to tank

LT1


LS1

 

I also followed that fuel line diagram to a "T". And it looks beautiful (not 100% done , but almost )

 

I just prepped 3 '89 harnesses. They are very similar to the 90-92 TBI with the VSS running through the C100. To use these, the buffer box must be bypassed and the speedo signal send through the C207(same pin actually). 85-88 cars had a separate connector near the C207 for injector fuses. Ill cover these when I find one

They also ran the fan fuse through the C207 and changed the wire color from BRN to TAN/WHT. I remember from a while back that someone said the fuel pump wire ran through the C207. It doesnt, it still uses the same pin as posted above in the C100. The fuel pump wire that goes through the C207 is for the ALDL bypass and is generally cut out in the prep. Theres no point in keeping it since the OBDI ALDL is being removed/made inop and the OBDII ALDL has no provision for direct fuel pump control. This is true for the 90-92 cars as well, s dont be confused when you see a GRY wire spliced into your oil switch and fuel control in that area

 

Hey, I just wanted to add this for the fuel line diagram. I originally was using every single part number you had listed on that diagram, but the stainless line, being very thick and bulky, wouldn't bend short enough to go where I wanted it to under the engine bay, so I removed the RUS 610020 on the fuel rail and replaced it with a 90* swivel, part number RUS 613160. The reason for this is because with the SSW long tubes, and the thickness of the fuel line, the fuel line was way too close to the header going the factory route, so I re-routed it behind the block and down the transmission tunnel, and it comes out by the cross member, avoiding the header completely.

Before with the RUS 610020 (it was angled too high for my opinion, because I had to bend the fuel rail when using truck coils)





And now with the RUS 613160

 

I have the same problem and decided to go with a 90* swivel as well.

 

Noted

http://www.ls1tech.com/forums/conver...oc-swap-6.html

Spike used almost all 90*s. Ill update the diagram

 

Nick, where did u get you SS braided lines ? did they come precut lenghts with fittings crimped on the ends or di u have to make it ?
part # and place would be great.

Also the black braided lines that Spike-Z used looks awesome. links for that Spike

 

I got it from Jeg's, I will try to get the part number after work. I got a 20 ft piece, it doesn't come with fittings, you have to put them on yourself. I got the -6AN size line.

 

New fuel diagram


Pic of the connections needed. This is a LS1 harness, but LT1 and others will be the same


VSS buffer box


Schematic of the box
http://www.austinthirdgen.org/mkport...SS_V8_vinE.jpg

Connect pin F to pin C. In the schematic its BRN to BRN. In the buffer box pictured, its BRN to LT GRN. After the connection, the box can be removed

Starter relay


Starter schematic
http://www.austinthirdgen.org/mkport...n8_starter.jpg

Two options to bypass this to start the new engine

1) Splice the two heavy wires together. This cuts out the relay and relies on the shifter (auto) or clutch switch to protect against in-gear starts

2) Ground the BLK/YEL wire. This retains the relay but satisfies the circuit. Using a hidden toggle switch to ground the relay makes a simple way for anyone to give a measure of anti-theft to the car

 

where is the starter relay located on a thirdgen?

 

Edit

 

Tracing each indiv wire until it had a C207 connector was how I made the 90-92 diagram up top. Why GM didnt put that info in the diagram from the start Ill never understand

Anyways, here are a few more years
90-92



89

 

88

88 C207 missing

87



86 Hard to read, sorry

86 C207 missing

 

85

85 C207 missing

Berlinetta's had the VSS wires going through the C100 like the later TBI cars. These are not used in the swap and the buffer box must be bypassed like above

84


84 C207 missing

 

83
missing

82

82 C207 missing

 

How the prepped 90-92 harness should be


Basic power dist of the LS1 swap harness

 

Ya, 90* works best. They are a lot more expensive then the standard straight fitting, but the fit is perfect.

I got it from Summit. Its a -6 nylon wrapped fuel hose. I loved the look and the material is soft, so when it rubs against the body, it doesnt scratch it like stainless would, plus its good up to 300psi... good enough for us.

 

Adding a bit more info about an 87 harness I just did. 86-88 are very similar so this should be helpful

First, the 87 C207 pinout is WRONG. Pin D is not the fan fuse, it is the fuel pump relay output to the fuel pump itself. It is a very large (10ga) tan/wht wire. I verified at the relay with my multimeter before disassembly. Pins B and G are supposed to control the fuel injector fuses. They do not, Im not sure where they go but the INJ 1/2 fuses go to the separate connector near the C207

Im not sure of the connectors name, but it is a gray 6 pin rectangular connector near the C207 with only 3 wires going to it

A PNK/BLK INJ 1
B
C TAN/WHT Fan fuse
D PNK/BLK INJ 2
E
F

 

Coolant tube gasket PNs
GM 12551933 $7.49 each 4 req'd
Dorman 56390 $6.98 4 per box

http://www.thunderracing.com/catalog...vid=3&pcid=227

 

That's the 87 C221... Some may have a couple more wires in there (I'm pretty sure I have a blue one in there).

For the 87 C207, keep in mind these are for the base V6:
A: Brown, ALDL Pin C for the AIR system test
B: Red, ALDL Pin G for the fuel pump test connector
C: SES Brown/White controller wire to/from ECM
D: Tan/White Fuel Pump power wire that runs to C208 by the C100
E: White/Black wire for ALDL Data (ALDL Pin B)
F: Pink/Black, ECM/IGN Fuse power In
G: Black/Pink, GAGES Fuse power
H: Tan/Black TCC solenoid control
J: ALDL M Orange for Data link (scanner)
K: Brown, VSS Buffer Input to ECM
L: V6 harness doesn't use this pin
M: Black/White ground wire
N: Orange/Black, Neutral Safety Switch Input to ECM
P: Purple wire, unused in V6 app.
R: Purple/White, Crank fuse out to cold start injection.

I hope this helps a little, even though it's not for V8 engines.

 

It helps quite a bit. V6 and TPI engines are wired nearly identical. Carb/TBI are the hard ones that like to change every year

 

Tried to update my post before (blasted internet card!), should look like this:

For the 87 C207:
A: Brown, ALDL Pin C for the AIR system test
B: Red, ALDL Pin G for the fuel pump test connector
C: SES Brown/White controller wire to/from ECM. May be White/Dark Green (VIN H), and goes to something called a "light driver module".
D: Tan/White Fuel Pump power wire that runs to C208 by the C100 (TPI). FP/INJ 2 Black/Orange wire to auxillary fan relay, VIN H.
E: White/Black wire for ALDL Data (ALDL Pin B)
F: Pink/Black, ECM/IGN Fuse power In
G: Black/Pink, GAGES Fuse power
H: Tan/Black TCC solenoid control, Shift Light control for M/T cars.
J: ALDL M Orange for Data link (scanner) (Fuel pump relay control for VIN H)
K: Brown, VSS Buffer Input to ECM
L: V6 harness doesn't use this pin (Fuel pump relay to choke heater relay control for VIN H)
M: Black/White ground wire
N: Orange/Black, Neutral Safety Switch Input to ECM
P: Purple wire, unused in V6 app, Brake switch Purple wire to TCC, VIN 8, F, H.
R: Purple/White, Crank fuse out to cold start injection (V6). C/H FAN fuse out to auxillary fan, Brown, VIN H.

:edit: BTW,

 

for any wanting to run 6AN lines straight off of the LS1 plastic fuel tank, Summit part 15117 is a quick connect to female fitting that costs 35 dollars. it should allow you to connect directly to the plastic off of the sender, then use a male to male fitting then a straight through fitting to your braided line.

i made a drawing of my fuel lines for a plastic tank to an LT1 rail (kindof a mix up, i know), and my total cost in fittings came out to 166.44 dollars, which ranges from 240-270 dollars for the entire system when you add 20 ft. of braided line, depending on wrapped coated or bare.

 

http://www.summitracing.com/parts/RUS-640850/ About half the price of that Aeromotive fitting, no other adapter needed.

 

I didn't know that would work off the plastic tank fittings- thanks for saving me 40 bucks!

 

okay, i see where on the ls1 pcm red pin 44 will operate the reverse lockout. is there such a pin on an 03 truck pcm with the green and blue connectors though?

 

Doesnt look like it
http://www.lt1swap.com/2004vortec_pcm.htm

Repin it to the 99-02 style or run it off the brake switch outlined in this thread
https://www.thirdgen.org/forums/faq-...questions.html

 

Pocket I wanted to say thanks for putting together all this info. I think there is one error on the 4L60e connector. The earlier pcm’s may be different, but for the 99-02 LS1 pcm, the 3-2 shift sol should be B79 not B78.

 

http://www.lt1swap.com/pictures/16_a...amp_switch.gif

You're right, thank you

 

this is another wicked write up by you pocket and thanks again for the info

 

I have a question regarding the large pink ignition wire coming from the C100. What are you guys using this for?

I have the injectors and coils hooked up to the two IGN fuses coming from the C207. I have the O2’s coming from the emissions common on the C100. I have the PCM and MAF hooked to the PCM fuse at the C207.

 

Some swaps dont use it at all

 

I am debating what to do with it, I am running all of my wires for power circuits and DLC through the speedo cable hole with a grommet off of the LT1 harness and not using C207 at all. It will make things much cleaner on the passenger side of the motor.

 

I have the IGN common powering my HO2's. (ask me how I know)

 

so to bring this back from the dead is there a breakdown of the 89's c207 wires and the c100 the way the first diagram was done? i did the 92 by hand myself before coming across this using a FSM but i dont have one for the 89 i tried using ATGO's diagrams with little luck

any info would be greatly appreciated!

 

Identical except the fan fuse was moved from the C100 to the C207 pin D and all engines used C207 pin K for the speedo via buffer box. C100 F8 is not used because airbags were not introduced until 90

 

Pocket you are ever the life saver around here! ill have to do some homework and post up in a new thread with any questions i have from there i really appreciate your help

 

https://www.thirdgen.org/forums/elec...ml#post5156537

pocket, this guy needs your help bad.lol

he has a 91 tbi car,reppined to use a 1987 ecm and cant get the speedo to work

 

can you post a full diag for my 89 rs 2.8l the autozone one wasnt quite extensive enough

 

Read post #20 above......

 

hey guys,

did anyone download these schematics from Pocket? it looks like they are not available at the moment. I need anything related to the 87 305 TPI.

Thanks

 

I've got this






http://berlinetta.info/C100.htm


I don't have anything on the C207 connector at the moment.