Re: LS1 harness: Start to finish
 

you're the man pocket...:goodjob:

Re: LS1 harness: Start to finish
 

pocket, do you do every harness anyone sends u like this?

Re: LS1 harness: Start to finish
 

Yes, LT1 and LSx

Re: LS1 harness: Start to finish
 

will this pinup fit a lm7, or is it strictly ls1?

Re: LS1 harness: Start to finish
 

Any 24x LSx using a 4896 or 0411 PCM (most common two). Also fits 58x LSx with the leignfelter conversion box

Re: LS1 harness: Start to finish
 

????????

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is it ok to cut the grounds, then sauter them together later?

Re: LS1 harness: Start to finish
 

Those are the compatible PCM serial numbers for that pinout. 24x/58x is the crank reluctor type. The older PCM cannot understand the newer reluctor so the converter box changes a 58x signal back to 24x so the older PCM can be used to control the newer engine

LS1/6/99-06 truck engines are all 24x

LS3/4/7/9/07-present trucks are 58x

LS2s can be either way, check before hand

Yes, cut the ground commons and solder them back together at the end

Re: LS1 harness: Start to finish
 

on the pinup provided, it says #8 put tps reference and it says the wire is grey, all of my wires aregreen or blue, which one goes where???

Re: LS1 harness: Start to finish
 

What kind of wierd harness are you working with?

A GRY TPS 5v ref
B BLK (or PPL) low ref
C DK BLU signal

Re: LS1 harness: Start to finish
 

never mind i had the wrong sensor, i have very limited info on these types of motors, but on the blue pin place, #8 doesn't have a place for the pin to go, so i looked up a pin up particularly for 4.8's and got that fixed

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do you have to put the 02 sensors in? is there any way you can have a pcm tuned to do away with those?

Re: LS1 harness: Start to finish
 

Fronts are required, rears are almost always deleted

Re: LS1 harness: Start to finish
 

pocket i've got a real bad feeling about this wiring, also i have a few more questions...
1. does the alternator hook into the PCM or the car harness?
2. is there another name for the MAF, because i can't find mine anywhere
3. the crank sensor i have is cut, what do i do to fix that
4. PLEASE HELP ASAP!!!!

Re: LS1 harness: Start to finish
 

1) PCM

2) MAF, Mass air etc

3) Use a 3 wire MAF connector from any 90's GM car

4) You lucked out because i sat down for a break just now

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do you know the specific pins that the ALT goes 2? if not i can sit down and look through anll of the pins i have and see, did i make a bad choice by using a 4.8 PCM pin up?

Re: LS1 harness: Start to finish
 

do you have a thread on this particular step?

Re: LS1 harness: Start to finish
 

Subscribed

Re: LS1 harness: Start to finish
 

Alt R15

Additional info thread

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Where did you get your constant power for the ecm and o2s?

Re: LS1 harness: Start to finish
 

PCM/Fuel battery 12v come from the 20A fuse near the battery

HO2s are on the PNK/BLK emissions fuse from the C100

Re: LS1 harness: Start to finish
 

Damn dude! Thank you for this thread. I have saved this for when the time comes to do my swap. :goodjob: I appreciate it!

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My red 'caps' for the PCM connectors are broke. Any way to get replacements?

Re: LS1 harness: Start to finish
 

this is my 1st post here (found link on NastyZ28), and i have read lots of wiring posts. this one is the easiest to follow and very thorough. should be a Sticky.

Re: LS1 harness: Start to finish
 

JY or EFIconnection

You can use any color instead of red, just shave the little tabs off with a razor

Thanks, it is a part of the LS1 swap sticky up top. If you know any other good wiring threads please add them to the forum. You can never have too much instruction

Re: LS1 harness: Start to finish
 

Hey Pocket, nice writeup!

Any idea how much wire you used (the red stuff) to extend the harness for the 3rd gen?
Also, what gauge do you use?

Re: LS1 harness: Start to finish
 

this is by far the biggest headache of my life. completely depinned harness, not a single pin or connector labeled.

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bit of a side question but is there a special tool to depin the harness? ive asked and had yes and no answers, i cant seem to get any of them out. maybe im just doing it wrong

Re: LS1 harness: Start to finish
 

i used my fingernails. if you push the pin in slightly before lifting the retaining tab it might help.

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i shall try thanks

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I use a pair of small flat head screwdrivers

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Has anyone installed the E38 pcm and harness into a 3rd gen?

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i have a question about your pinouts. is that set up for a manual trans car or auto?

Re: LS1 harness: Start to finish
 

Both

You ignore the parts that do not apply to your build IE, If running an auto, the reverse lock, CAGS are both irrelevant

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im so lost on the whole ls harness I got my 91 harness done but idk were to start on my 5.3 harness im so lost idk what half the connectors are and the whole c100 c101 c105 220, 230 im completely lost on I got all the pin outs for my pcm but idk were to start and were to connect to third gen harness and im switching to a ls2 intake from a dbw truck intake and idk were I need to pin for the tps iac etc im just so lost any kind of help or more indepth would help ik I gotta change injector plugs since im changing intake I have a 04 5.3 harness and pcm im new to all this stuff and I think I did third gen harness right but idk and the truck harness has the fuse block idk what to do with that just any kind of help will be good

Re: LS1 harness: Start to finish
 

You may want to start by researching the 04 PCM, in regards to it being a drive by wire PCM. As far as I know, the 04 PCM cannot be converted to a drive by cable configuration. A 99-02 PCM would be ideal, but if you have the electronic gas pedal and TAC module, the drive by wire can be retained.

Pocket has a thread here somewhere with pictures, to help identify plugs, so you can easily decide what you need and what goes.

Re: LS1 harness: Start to finish
 

The 04 gto is drive by cable and it uses the same PCM I'm gonna print the pin outs for it tomorrow I just got off the phone and they explained it to me I think I got it at the moment and iv done a lot of reading on all this I have the parbt number and connectors the harness Prep and this fourm lots of times

Re: LS1 harness: Start to finish
 

Your previous post said you had a 04 5.3 harness and PCM, which most would assume is a dbw truck. GTO was either a 5.7 or 6.0. Just be sure you know exactly what PCM you have so your harness is pinned correctly.

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I have a 04 blue green PCM but I'm gonna check all data today at school

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Alldata wont have the answer on the PCM. You have to open it up and look for yourself

If the PCM came from a DBC engine, it will work. If it came from a DBW engine, you have to inspect

http://www.lt1swap.com/cable_conversion.htm

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Where do the pink and black wires from the Bank 2 Sensor 1 oxygen sensor go to? Can't find them in pinouts

Edit: ok, I get that they don't go to the pcm because they don't have pins. Where do I route them?

Re: LS1 harness: Start to finish
 

Link is ignition 12v supply, black is ground. These wires do not go to the PCM.

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I have completed the DIY harness 99 LS1/4L60E combo into an 87 S10 Blazer. All of the wiring schematics were bounced off of this post, the famous "DIY LS1 swap into anything" book, Blazer wiring diagram and the 99 Camaro wiring diagram. I have everything installed and sitting in nice and pretty, but when i took it on its maiden trip felt some issues.
On acceleration.. shifts from 1st to 2nd harsh enough to chirp tires, 2nd to 3rd normal, 3rd to 4th normal. However.... cruising down the highway about 65-70mph it only stays in 4th for about 15 seconds, acts like it shifts into neutral for about 5 seconds then downshifts.
I have hooked up an LED light to R42 "TCC enable circuit" to see if the converter was locking up when its supposed to(haven't driven it since). I also noticed i did not have anything hooked up to B33 "TCC Brake Switch". Would not having a 12v power source hooked up to B33 affect the shifting of the transmission? and do you have any ideas on a fix?

Re: LS1 harness: Start to finish
 

If theres no codes, chances are the wiring is fine. Can always double check it though by ohming out the circuits between the PCM and trans. Open circuit means issue, but it will almost always throw a code of some sort

Ive never not wired the brake switch in, so I cant tell you the symptoms related to it, but I can say it is required. Your 87 will have a compatible switch on the pedals, so wire it in and see if it helps

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Thanks Pocket!!:thumbsup:
Ill hook everything up today and see what is going on, may not get to drive it though... we got about 6 inches of snow last night and don't think that would be a good combo..lol! I am hoping that it is something simple like that.
I did the completed swap and wiring in a month and a half last Mid- October/November and have been working out gremlins since.... kinda one of those frustrating, ongoing deals.

Re: LS1 harness: Start to finish
 

I have a question im doung my wiring and i cut off the fuse block now my question is i know the pink needs to go to the ignition switch and orange to the battery but what do i do with the rest of the wires that were on the fuse block? I need help asap

Re: LS1 harness: Start to finish
 

im guessing this is very similar to lt1 harness but just a question my harness has four connectors into the computer how would I go abouts getting that done ive got a 97lt1 t56 out of a z28 going into 91 z28

Re: LS1 harness: Start to finish
 

https://www.thirdgen.org/forums/ltx-...rt-finish.html

Give this a read

Re: LS1 harness: Start to finish
 

Wow, this thread is incredibly helpful... I wish I'd found it before I got neck deep in building mine from scratch :doh: Just another one of those things where I do a bunch of research and think I have it all under control, then get part way into it and realize I have no idea and end up spending too much money :lol:

Oh well, live and learn. When I'm done, I'm going to have one helluva harness :thumbsup:

Re: LS1 harness: Start to finish
 

Thanks for the great write up. Is there any way you could show me how you wrap the harness after you get it complete?