chevyredneck8

iTrader: (4)

This is my removal of my factory wiring harness and computer. It may take a while for me to load everything on this site and ill add to it as I figure out more. I'm trying to be detailed for any first timers on projects like this feel free to ask.I separated the harness from the factory section I needed AC, alternator, lights, wiper motor etc. Then integrated Holley's wiring harness and ECU into the section I still needed.

My suggestions before you start 1st find more than one wiring diagram for your car. I had Haynes, Chilton and a third party diagram and found imperfections with all 3. 2nd take plenty of picture as you make progress it can always be helpful to have something to look back on or you can later share with others to help others out. 3rd take your time a label every plug and what sensor or where it guess. This will be helpful if the color of the wire is faded or you find an imperfection with the diagram.

Pull the inner passenger fender liner and kick panel. There is plugged connection that disconnect the computer and the two additional plugs.

Then start working through the complete engine harness unplugging everything including relays and grounds. On the drivers side firewall wiring harness plug there is a small bolt that can easily be overlooked be sure you unbolt it first before you go pulling.

chevyredneck8

iTrader: (4)

The above pics are a few or passenger side. Dont forget some wires that go to the cruise control and lights do not need removed they come out the drivers or firewall separate from what I have mentioned.

chevyredneck8

iTrader: (4)

Next Lay everything out the plastic that came through the passenger fender has a factory glue. The best way I found to remove this was a heat gun heat a section up till its guey then pull it out with a rag till its out. Then remove all the plastic protective casing.

The next step is figure out what sensor or inputs you need to keep and what wire use the same connections. One is hot in run pos mine looks like this. The next pic was my color code for the trans plug you shouldn't need the 4th gear reference but hook the tcc up if you want to retain lockup through wiring up a relay ill explain how later. then black or black w/white is generally ground and will have to be separated through out harness

chevyredneck8

iTrader: (4)

The way I did the fan relays was I keep both of them. Orginally One is tied into the factory computer and the other was tied into the temperature on the passenger side of the engine. These trip on ground. So I have both of the relays tied together (both fans turn on together)I have mine tied into the Holley ecu which Ill explain how you set that up later. The important thing is to have them tied together also I tied in the AC sensor so if that turns on It will turn fans.

I also wired an additional fan switch to where I can turn on my fan when I want. I had an issue when I was tuning and reloading the holley ecu It would say hi temp coolant sensor error and wouldn't turn the fans on. It is some type of software bug holley engineers may be trying to figure out now.

Orange or red was generally always hot. The tan w/white strip is hot when ac is running

86ZRESTO

Chevyredneck,
I am actually going to do the same 383 hsr setup this year. I would like to pick your brain a little about the holley ecm and the slow ecm from factory. Would it be cost effective to have tpis burn a chip for $500 for stock ecm or just bite the bullet and and go with the hsr ecm.

chevyredneck8

iTrader: (4)

I've seen people with mix results trying to order chips. It could be the cheaper route, but the best tune would be something you can fine tune. Also if you change something later head cam etc. You have a tunable system. Plus wide and is I nice feature to dial in your afr ratio.
I'm still going to take mine to a shop to tune and dyno it. I've driven it about 30miles but its still running way to rich and the self learn isn't pulling the fuel out unless I'm doing something wrong . I'm going to tinker with it more next week when I get it back from the exhaust shop. I was hoping to get a very close tune with this system and have a professional do the final tweek.

Also what car combo do you have now you have to factor total cost wiring harness, sensors etc.

86ZRESTO

I read a forum on a direct swap from a tpi to an hsr at a 1/4 mile test track. The ran 3 passes with the tpi set up and then swapped to the hsr on sight and made three passes. First pass was a bit sluggish so they bumped up the fuel pres to 48 and set timing to about 32 btdc it ran very rich. The last pass they backed off the fuel pres to 42 and brought the timing to about 29 or 30 and the car pulled hard on the line and dropped their et over a full sec over the tpi. I was wondering if you had tryed playing with fuel pressure and timing to help with the tune a bit.
I have an 86 Z28 yellow with grey 305 tpi. Ive had the car 6 years and finally getting to put a motor in. Ive already updated all suspension and some extras underneath but im ready to retire the 305. It is drivable but i dont trust it any farther than the inspection station which is only about 3miles. It is not a dd so it sits in the garage for the most part. I am putting a 383 stroker alum votech heads 202i, 160e and a health cam
in 230 to 240. I have been looking at the hsr with ecm to eliminate the stock computer as well just because they are so slow. I am planning on keeping my trans and do a good rebuild on it and swapping my 273 gears for 342s. I have read a lot here at third gen over the past 3 or 4 years trying to decide on a setup what has worked and what hasnt. I grew up building muscle cars and engines ect. But the electrical i find a little intimidating. But i kniw once i start it i will figure it out. Sorry for the lengthy message but i will be following this thread closely. I would like to know more about your eng and drive trane.

chevyredneck8

iTrader: (4)

I'm going to try to explain everything fairly simple if I leave anything out or don't explain something enough ask. I used a standard NOS relay for tcc the following pictures explain the wire layout. The relay was original for a positive setup but can also be used for a ground connection which is needed for tcc.
The green#85 is the ground switch from the ecu.
The orange wire #30 goes to tcc switch
The red #86 goes to a positive
The blue # 87 goes to a ground

chevyredneck8

iTrader: (4)

Two more pictures for the tcc relay

86ZRESTO

I would like to ask a question about engine preference. I dont want get off topic or hijack your thread. But i am still undecided on an engine and wanted your opinion. I already have a 383 picked out and total cost will be somewhere around 7k. But i can also pick up ls1 for around 2 to 4k with harness, ecu and some with trans. And i can also pick up ls2 eng, harness, ecu and elec ped for around 4k. Both have everything on the eng. How is your 383 as far as fuel econ. A lot ppl say 383 is good for stop light to stop light but not at passing on hwy. Is the power range good at top as well as off the dig. Thanks for any input on this matter. The pics will definitely help in detail

chevyredneck8

iTrader: (4)

I can't really comment yet on fuel economy yet as I'm still playing with a very rich tune. Hopefully within the next month in going to take it to be dynoed and final tune and can give hp and fuel economy w/the supercharger. I'm hoping for 15+ on city and 20+ on trips maybe even more if I dial back the gear ratio when I rebuild the rear end.

As for people making speculation about 383s it depends a lot on how you build the motor IE heads compression ratio,cam down to degreeing a cam,headers,intake etc . Some people build them 13 to 1 compression & with cam that doesn't come in to 5k and make little effort on the drivetrain or tune to help fuel economy and you can get sluggish midrange and poor mpg.

My 383 with 9 to 1 compression is probably one of the best feeling na motors I've been in which surprised me since I did build it lower compression for the SC. Its balanced and seems happy to pull above 6k and likes a midrange kick. It reminds me of an old school 327 the way it likes to turn up and with the extra cubes it has a lot more grunt even in the bottom end.

LS motors are great but before you dive in too far on any one setup ask your self what your ultimate setup is and plan for that goal. If your looking for just 400hp streetable or would rather eventually have 600hp supercharged. Also look at total cost. Wiring harnesses , accessory drive, drivetrain and conversion parts etc. Sometimes the engine is the cheap part to buy.

I personally wanted to build an LS7 but could never find one cheap enough. Then the ls2s I considered by the time I would have upgraded the internals it wouldn't have been cost effective for my goals but I started buying part for my build in 2010 and ls2 have came down In price alot since then .

86ZRESTO

Thats where i am now, i saw an ls2 on ebay the other night going for just under 4k but i was hesitant. I probably should have jumped on it but i got to thiking about ok it has 120k miles on it so it needs to be rebuilt then there is the trans and the time to make it fit and it wont stop there with little odds and ends. Your thoughts have helped me greatly. I am looking for 400hp at the wheels and be streetable. I want just a mild cam nothing radical. 9.1 to 10.1 would be sufficient. The 383 i am looking at comes with a 230 to 240 cam would this be too much for what i am wanting or do i need to dial it back? What cam do you have? Going this route i think would be a lot less headaches and cost less in the end. Thanks for your time.

chevyredneck8

iTrader: (4)

This is the pic for the fuel pump. I tied mine back to the factory fuel pump relay and will probably going to redo later with a new relay mine has a couple wire exposed near the connection.
The black/white is simply a ground.
The two oranges one goes to a positive feed and the other stays connected to the driver firewall connection.
The tan white is run in hot
The green is tied bad to the Holley ecu green wire . This is a direct feed and could be tied directly into a pump up a certain amp rating.

chevyredneck8

iTrader: (4)

My cam is less aggressive but if I was going solely na I might would go more than an lt1 hot cam which is what I have. But my thought process is a slightly less aggressive cam will make it a pull better in the lower rpm low boost but still aggressive enough to to feel like a bigger cam higher in the rpms once the boost builds.

For Na I'd still suggest at or above above a 10 to 1 or better which is still plenty streetable.

For 400hp an ls2 isn't a bad choice plus the tune is kinda simple since the ecu is set to run that motor and I wouldnt be to scared of 120k unless it was really abused some people are already getting 200-300k miles on them.

chevyredneck8

iTrader: (4)

This is color codes for the 4 inputs and outputs that you can program.
This is an an extra harness to buy it didn't come in the main harness.
The paper is what color code goes to which pin and are assignable.
There is 4 outputs two negative and two positive and the same for the inputs.

Holley currently doesn't list the color code in any manual for this input/output harness. I had to call tech support to get this information and they said hopefully they will have it fixed soon.

I went and setup my my setting for tcc and fans and assigned the pin to the specific wires.
These are the same wire you could setup for now, 2nd fuel pump, AC reference, etc

First 89Formula

Son and I project/mod also going to the avenger stealth ram tpi system wiring is fun job NOT LOL

Question on this wiring for fuel relay. Got it all except the tan/white wire it was it going to fuel relay,maf relay (which be gone), trans and to old ecm (we got the avenger efi) then into firewall into car would this wire into car be the run hot wire? or does the old wire to ecm need go to run hot wire?

chevyredneck8

iTrader: (4)

The tan/white wire should be hot with the switch in the run position. You need to keep this tied in through the factory wiring. Cut unnecessary section like maf and tie in the new items that need hot in run position. The Holley ecu will also need a connection. Other wires may be hot all the time. My setup has the ecu completely gone and none of the old wires come from the passenger side fender other than the new harness coming from the Holley ecu.

Exceptions to this may be if you have an electric Speedo of other features that are connected to the factory ecu for piggy back purposes. Mine is an 88 with mechanical Speedo and cruise so I had no need to piggy back

First 89Formula

Awesome thank for reply. We did keep the fuel relay and trans wired into the factory wiring that goes into firewall on drivers side tan/white wire we just need make sure this in hot in run position.
Holley ECU we still need find a place to hook the wire (red/white stripe) in the run/crank position.
Other red one to battery but heard really not good for it since dirty noise there if other things ties into it. Where did you run this wire too? Per Holley says goes to battery. Hope ok with question first time son and I doing car like this J
We do have wiring diagram for his car fun trying to find correct ones.

chevyredneck8

iTrader: (4)

The two main wires I made a connection directly to the battery. Which is what Holley recommends in the instructions if I remember correctly. The rest I tied back Holley ecu wiring into the factory wiring coming from the drivers firewall tie in. I'd still use the wiring diagram for your year and model. And u can always use a tester and hookup the wiring and confirm what is run in hot, always positive &ground.
Another option is those wires can also be found inside the car.
So far I haven't noticed a random sensor live feeds like I have noise interference from other wire.I also grouped and ran those together and they are in wire protection almost the whole way

thatsupnow

Hey man regarding your fans, did you separate the factory relays and wiring for the fans from the factory harness and then used the grey/black wire from the holley harness to trigger ground?? thanks in advance

Update: Got the fans working no problem I ended up not even hooking it up to the holley. Its was super simple I just took the green/white wire from the primary fan relay and put it straight to a ground now both fans come on when the key is in the "run" position

thatsupnow

Any idea how to hook up the vss to the holley and out to the speedo?

chevyredneck8

iTrader: (4)

I have mine set up through the Holley wire output which you set which wire is the input /output .There is two ground wire that you can use look at the wire diagram for input/output I posted.. Because why run fans all the time if you dont need to. When the ac comes on it also trips the ground to turn the fans on. I also have two switches that I can completely turn the fans off of have them continuously run when the car is running.

The reason is if the temp sensor was to fail or at the racetrack I want the fans to always run between passes to bring the temp down more.

The reason I have the off switch if I'm on the interstate and taking a 3 hr trip @ 70mphs I see no need to continuously run the fan when more air is naturally being pushed through the radiator than the fans can do. Its a slight drag on the motor though dont know if the V8 can even tell the difference lol

chevyredneck8

iTrader: (4)

Holley has a speed hookup I have the 7" touch screen and it has an input for a Speedo but I have a mechanical Speedo so didn't look into that setup though some of the sensors I know you can set the calibration for input so Id imagine electronic Speedo would be the same though I'd call Holley tech to make sure u don't need any additional wiring hookup or buffer box. Also post what you find on here for other peoples reference!

thatsupnow

Yeah I guess I could just not be lazy and take that green/white wire I put to ground and just hook it up to the holley. But yeah Im gonna dig into this electronic speedo and anything I come across will be on this thread! How you liking the system? Ive been having a blast the motor has been running sooo much better then with the custom chip I spent a small fortune on.

thatsupnow

Hey chevyredneck8, how did you go about sealing up the hole where the factory harness came into the car? I used some mono foam to fill in the bulk of it but now when it rains the water rolls right down the harness and I end up with a big puddle of water. Thank goodness this ecu uses weather pack connectors or it be screwed already

thatsupnow

Im just gonna leave this picture here just for anybody else doing this system. The wire being pointed at is the green/white stripe wire from the primary fan relay. All I did here is cut the wire and sent it to the holley ecu ground trigger and BOTH fans come on at the same time.

thatsupnow

This is where I ended up mounting the ecu. Its tucked up and no feet can hit any wires. But I did cut the section a lil big out of the kick panel, but that's okay Ive got another. I found it a little bit hard to seal off the cab cause of the mesh wire loom used any water went thru it and rolled in to the passenger side on the wire pooling up.