Subscribing and a quick question.

You refer to "commons" e few times. Are these ground wires or just specific wires grouped/connected together?

My term for grouped wires

Thanks. Just had to clarify for me is all.

The pics don't work... Was going to use them for reference while stripping my 89 harness and adapting it to a 01 LS1 harness. Is it on my end or are the pics not hosted anymore?

Bandwidth is maxed for the month. Give it a few days to reset. Usually mid month

I was wondering about that too as I am about to start my harness and was freaking out a little. The believe the write up should be enough, but the pics you have up are definitely a huge help to all of us. Thanks for the info!

so pics should be back up middle of the month ish?

I was wondering if I could use a s10 PCM and harness or just a complete harness and add the extra injectors

Need a few more connectors beyond inj, but s10 4.3 harnesses have most of what's needed

01-02 s10 pcms were 0411 just like late ls1/truck

I have a 6.0 so will that work

The S10 PCM will work fine on your 6.0. Using one on mine currently

Thx!!!!

just what i needed to know. will pcm require a tune? what else will have to be added to the harness?

No factory PCMs will work without a tune, so it doesnt matter what it comes out of as long as the service number is compatible. V6 S10s are super common and the 0411 PCM is well established. Ive got a shelf full of them for that very reason

Link to wiring diagram I created for my LQ4 swap using 0411 PCM into a 1986 IROC. It uses a Current Performance Wiring fuse block.

https://www.thirdgen.org/forums/ltx-...ml#post5841970

*no where did i see anything posted for any intro-newb "redbelly" entry hazing pre-posting?*

i hope that it is cool to belong to this forum?

because i did own the 1984 H.O. w/a 5 speed z-28. wikipedia shows a 305 h.o. only available in the Iroc in 1985 w/an automatic at $11k-13k. well i payed $16K and ordered mine w/the H.O. 305 and a 5 speed in late 1984! it out ran Iroc's with the 5.7 on take off back in the day! i mean the only part i had to replace was the fuel pump and it was a "H.O." that was a few IBs diff from a 305 and basically a 350 fuel pump. i also did have a Pontiac 2001 TA. but it was totaled and it will live on in a truck.

i really was looking for a wiring harness guide to re-wire to engine guide. this diagram/photos are by far the best that i have located. i have several wiring schematic books, but i wasn't there when my engine was swapped. and i am getting the wires redone & the PCM re-prog'd. and i will attempt to re-wire it myself.

If it was a 99 harness there would be no need to un pin the two connectors right? You would Just have to remove the wire you don't need.

I depinned all of them regardless of year or vehicle class. Read on to where you lengthen/shorten the wires to fit the new PCM location. It'll be 10x harder if you leave them in the connectors

Pocket, are you getting caught up? I still need a C100 harness.

Pocket. Wouldn't you just do one wire at a time if you wanted to lengthen them? I think defining the entire connector is way to difficult well atleast for a first time swapper like me

Makes the whole soldering procedure easier being able to separate a wire out from the bundle, and fully pulling the harness apart down to individual connectors allows you to rebuild the harness slimmer and simpler.

Honestly, takes no time to pull a wire out from the ECM connector and to push one back in once you've lengthened it.

Hi Pocket,

I've just been going through my harness with a multimeter to make sure the pins all match up to the connectors they're supposed to, and I've completely forgotten about relays.
Do the 0411 PCMs not need relays, or are the relays part of the body wiring that you hook into via the black plug wires that are connected to the c100, c102 etc?

I was thinking that I would need the following relays:
AC
MAF
MAF burnoff

Are there any others I would need, or are these not needed?

I pulled the TPI wiring from the car as well as most of the engine bay wiring when I started my rebuild, so I just need to know what needs to go back in.

A typical LS swap will use FP, Fan 1, Fan 2 and AC

I prefer to run the relays last as they only have a trigger wire to the PCM. Everything else is external to the engine harness

Fuel is simple, PCM triggers the relay, direct to pump

Single fan swaps use the low fan point only
Dual fan cars do ^ as well as a second relay from the high speed point. When the low speed command is enabled, one fan comes on 100% while the second remains still just like 3rd gen fans did. When the high speed command is enabled, but fans engage

AC depends which you use. LSx low mount I use a PCM controlled relay with 3 wire pressure sensor emulating a 98-02 Fbody AC circuit
3rd gen R4 and sanden high mount compressors are wired like 90-92 Fbody TBI AC circuit direct from the HVAC head unit with a PCM reference. The stock hi and low pressure switches regulate pressure

MAF and MAF burnoff relays are part of the 3rd gen wiring and are not reused

Thanks for that. Sounds easy enough.

I have a TBI AC compressor with the 3 pin plug on it, but using an old OLD school HVAC from the 70s that I'm modifying, and it just has an on/off switch and fan speed switch so I have to wire it from scratch.
From what I can gather, I need a relay for the fan on the condenser, one for the compressor, and pressure cut off switch, does that sound about right?

http://www.austinthirdgen.org/mkport...al_V8_vinE.jpg

Thats about as universal as it gets. 12v goes from the HVAC head unit to the compressor clutch with feedback to the PCM. Hi/lo pressure switches break continuity if the pressure is outside of the acceptable range

High pressure switch is on the rear of the compressor, low switch on top of the HVAC box

I couldn't find it in here, I'm swapping a 4.8 in to a 86 iroc. Just wonderig if some one could tell me roughly how long the harness needs to be from the back of the motor to inside the car. I'm ok with it being a little to long. I just don't have my car here and wanna get the harness finished. Thanks
Oh and pocket this is awesome

From memory I think it was an extra 1-2 foot would give you the length, but that's only if you're routing the harness the same way.

I'm using a commodore harness for mine and going straight through the firewall so that I only have to extend the CKP and that's it, but I guess depends what you're doing with the harness route.

Also, probably wait for someone who knows successfully completed theirs and not my advice :P

2.5' to mount it on the HVAC box, 3' to fit in the stock location via hole under the HVAC box, 7' stock route behind the fender

Your the man pocket! Thanks

Hi.
I have a corvette 5.7 engine wiring harness and computer SERV, NO. 16,232,148.
I have been told. that it can not control a 4l80e transmission.

What computer I can buy the best. Can i use the computer and wiring harness from a 2003 Silverado 5.3 or a 2003 5.3 Avalanche. They are here on a scrap yard in Netherlands.
All tips are welcome.

Greetings Pocket, I too want to be a wire twisting hippie,
But from what I have found out, I need to go with the latest greatest stuff, which means a 03 s10 blue green harness to start with and a- last of the cable throttle pcms either the 07 express van 801 or the 06 462 because the engine is a 54 tooth reluctor wheel,, when seeing someone say--have the machinest press on a new "exciter ring" they are talking about the reluctor wheel right?


im sticking with the 03-7 pcms because ive heard they are the faster-optimal ones, I know everyone figures the 411 is the most popular but....
one question I have is the possibility of it having the potential to control something like the 12 volt stepper motor VGT mechanism on a Holset he341ve VGT turbo............ I know,, something from way out in left field,,
any possibility? or do I have to plan on adding on a programmable logic controller, like a hobbywing or a picaxe~ if you know what those are.

You want the 2002 or earlier blue red connector harness and the 411 pcm I think

Okay thanks.
Monday I'm going to look around at the junkyard.
Sometimes it's difficult to build American cars in the Netherlands.
But it's worth it.

I found a 2000 suburban 5,3 computer 09354896. Wiring harness i can adapt myself.
It has the drive by throttle cable chip (idle air control) in it.

I just hope that this computer can control the 4L80e gearbox.

Now i only need someone who can customize the software.

Holy Shyt --what a small world,, I was always into early Camaro's fil my 30's when I went off ol the old GMC tangent, and the ones I mess with are the COE versions of your HD 39, trucks like yours are almost non existant in America now.


http://dallas.craigslist.org/dal/pts/5260229476.html

I really like the tow truck.
Saw it neglected for sale in The Netherlands and had to save it.
Stays completely original exterior (fore now)
just needs more power

hmm does it got the 308 engine? manifolds on the Passenger side?

you can look here:
http://oldgmctrucks.infopop.cc/eve/f.../m/52620155373

Do not want to pollute the camaro ls1 haness forum.
Talking about gmc trucks.

Still need their help when I'm going to make the wiring harness

Ive done a lot of searching, and I found some info that I can connect the VATS wire to the Pin 30 on the red PCM connector.
Post #10 https://www.thirdgen.org/forums/ltx-...questions.html Will this work?

I got my new Pocket harness installed this week and was able to fire it up last night but it fires and sounds great for just a few seconds then shuts down. Research leads me to believe its the VATS in the PCM.

Will this work or does it absolutely have to be tuned out as you previously posted?

Thats a 97/98 PCM and you are correct it cannot control the 4L80E

Either of those truck PCMs should work. Check the service numbers: 9354896/12200411. If all else fails, look for a 01-02 S10/blazer or similar with a 4.3L V6. They all used 0411 PCMs which also work with a reflash

Thats VATS and you can build/buy a bypass box to solve the shut down issue. It doesnt address the other factors of the conversion such as emissions deletions

Does this mean the info I suggested won't work? It was the only place I'd seen it mentioned but seemed creditable.

I could build one but I'm having trouble making heads or tails of all the bits and pieces of VATS bypass info. I can't find one good thread explaining one or where I hook it to. I also can't get a ohm reading on my 4thgen key. Thirdgen key was 523.

Another difficulty I'm having is clearly distinguishing between thirdgen and 4thgen VATS info. I'm pretty sure my issue is just the 4thgen VATS but I don't understand it all well enough to be sure.

Can you point me to a "how to" thread for building one? Who else sells them besides Hawks? TYIA

VATS is an antitheft system, so its not just annoying it will disable the car. A bypass box will take care of it. The other systems are just annoying and will leave your MIL on until you either fix them (non-existant) or turn the codes off in the PCM. VATS boxes are usually $30-50, $25-30 DIY and a basic swap flash on a PCM $50-100. Not much savings for a DIYer

Ok, lets talk about how VATS works, hopefully itll clear up the modules and resistors questions

VATS is a security system to prevent any goober with a screwdriver from stealing a car. It consists of a resistance pellet implanted in a key and a matching VATS module. Put the proper key in and the module OK's it, then allows the PCM to fire the fuel injectors and starter. There are also two different types of VATS which isnt super important, just remember they're not compatible with each other beyond the key. Reason why a VATS equipped 3rd gen wont work with a VATS equipped 4th gen PCM without extra help

Now to bypasses
The resistor:
If you're running the same system that came with the car ie 3rd gen in a 3rd gen or 4th gen in a 4th gen then you can use a common resistor. GM only made 15 key blanks of different resistance values for all VATS system, so anyone with a meter can measure the original key and solder a matching resistor in before the VATS module. That way VATS is still active but permanently satisfied. Down side is you have to know the original value from the start, so if you just get the drivetrain/PCM you've got a 1/15 chance of guessing it

Next is the VATS module:
When the proper resistance value is given to the VATS module, it outputs a distinct signal to the ECM/PCM to energize the drivetrain. Bypass modules remove the original box and hook up a small box that outputs that unique signal to the PCM. No original info is needed

Tune:
This is the best option because it skips all above and is transferable to any vehicle the PCM is used in. Since there are other things in the PCM commonly changed in a conversion its helpful to clump all these things into one trip to the tuner. With tuners being so prevalent, its not hard to find someone to do this if you lack the software

1st question... Can you still load and unload a PCM if you are VATs locked out to tune it out. Or should I tune it out before hand?


2nd... Do you have any pinouts/links/tips on an older 3rd gen(specifically a 1985 z28) It had a factory carb. I assume I have to make some sort of relay/fuse box, for electric fans, fuel pump. Or any sources of schematics? Once I saw links to individual systems breaking it down, it made alot of sense.

The good news, is I have an entire running and driving 2000 T56 ls1 car that I will be getting donor parts from. At one point I am going to gut the ls1 car and junk it, just don't want to regret not getting some stuff.


Other questions, where do you source your wire? what is typically used? 18 and 20 guage? do you just do butt splices and heat shrink if you need to extend it the harness?

Tune anything in any order. The PCM wont be any use for a swap unless VATS is turned off though

A carb car will need a fuseblock added to protect the engine electronics. There is a diagram in the additional info thread along with pinouts for every year 3rd gen

I buy wire in bulk in two sizes: 18ga TXL and 12ga TXL. Everything that goes to the PCM is 18ga, heavy cables for power/grounding get 12ga. If you plan to do multiple harnesses, then its worth while to stock up on some new wire. For just one, Id grab a cheap mid 90's GM harness to scavenge wire from. S10, CK truck, van etc. For splices, I use a modified lineman splice; strip one end about 1/2" then the other about 1". Twist the two together for the 1/2" then fold over the remaining exposed 1/2" and twist again. This often pulls the wire slightly short, so tug it back to length and it will slightly unravel. Pinch it tight, solder, cover and youre done

Hey Pocket,
Sorry I think I've asked before, but just wanted to double check, what relays are needed for the LS1 PCM?
There's no MAF / MAF Burnoff?
Only Fuel Pump?

Id assume electric fans as well.

Fuel, Low fan, Hi fan (optional), AC (optional)

If a fuseblock needs to be added then an IGN relay is also required

ok i got my harness almost done but i have one black wire that goes to the pcm but cant figure out whre it goes. any help

Is it a black wire pinned in to the PCM and you can't figure out where it goes?
Or is it a black wire in the harness and you don't know where it goes on the PCM? If so, we need to know where it is attached to the harness at the other end.

Sounds like it is a ground for something simply because it's black, but lets not assume.