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Hello,
This my first post and probably one of many to come!
I recently purchased an 84 C4 Coupe Auto without the engine and transmission that had been stored for 20 years.
I’m in the process of swapping in a 6L LS LQ9. So far I’ve removed the ECM and engine harness.
I was able to find and download a few schematics from the internet but I need additional information on the following connectors.
There are 2 connectors that plug into the engine harness under the dash on the passenger side to the body harness:
(1) 8 pin grey plug
(2) 15 pin white plug
I hope someone has the pin outs for these 2 connectors, and also the pin out for the bulkhead connector on the driver’s side.
Thx.....LS Swap
Buy the factory service manual, you'll need it throughout the swap. The PDF version is about 50 bucks, eBay usually has old hard copies of the manual. Whatever you do don't buy the cheap Chilton's or Haynes manuals, you need the genuine gm publication.
Thx for the reply, I already bought a digital download of the GM service manual from Ebay that spans Corvettes 1984-1996, unfortunately it only has 1990 and 1996 diagrams. I'm hesitant to do it again because a lot of vendors just scan a few manuals and sell whatever they have.
If all else fails, my trusty multimeter and I will spend some time together probing the vette!
One is connector C455
Pin A = ALDL Pin 5C
Pin B = Vehicle elapsed time sendor gnd
Pin C = CE light
Pin D = Oil pressure
Pin E = ALDL Pin B
Pin F = ECM IGN FUSE
Pin G = power ( fron gages fuse )
Pin H = ALDL Pin F to Overdrive realy ( Manual transsmission )
Pin H = ALDL Pin F to TCC control
Pin J = Brake switch to TCC relay.
Pin K = VSS out from Dash to ECU
Pin M = GND to ALDL pin A and pprak/neutral switch.
Pin N = Park/Neutral switch ( Automatic )
Pin P = ALDL Pin E
Pin R = Crank
Other could be connector C467
Pin E = Vehicle elapsed time input
Pin F = A/C on
Pin G = Canister purge
Pin H = ALDL Pin G from fuel pump relay
Ptobably bulkead connector C100
Pin 1B = Power from fusable link A
Pin 1D = Ingnition to alternator
Pin 2B = Sensor GND to dash
Pin 2A = Power from fusable link B
Pin 2C = Coolant temp to dash
Pin 2D = Windshield wiper
Pin 2E = Oil temp to dash
Pin 2F = AC pressure switch to radiator fan relay.
Pin 2G = Distributor power
Pin 3C = Windshield wiper
Pin 3D = Windshield wiper
Pin 3E = VSS to dash
( Gahtered from schematics when swapping ECM to aftermarket )
Thx for the reply, I already bought a digital download of the GM service manual from Ebay that spans Corvettes 1984-1996, unfortunately it only has 1990 and 1996 diagrams. I'm hesitant to do it again because a lot of vendors just scan a few manuals and sell whatever they have.
If all else fails, my trusty multimeter and I will spend some time together probing the vette!
Yeah, as mentioned you need the official gm publication for your specific year and nothing else. I got mine off eBay. And it only has info on my year car.
Thx JoBy for the help, btw do happen to know what the 2 pin connector on C467 I believe it should be pin C&D with the Pink/Black and Tan/White wires are for. I assume the Pink/Black is Ign Power and the other wire is a ground trigger. The problem is the engine was removed when I purchased this.
This would be inside car under dash for an '84 @ ECM. You can see where the harness is pigtailed out of the cross dash harness and also pigtailed out of the engine harness passing through the grommet on the right side dash.
Connector C467
Pin A Red = INJ 1 FUSE Pin B White = INJ 2 FUSE
Pin C Pink/Blk = VSS Lo to dash
Pin D Tan/Wht = VSS Hi to dash Pin E Blue/Wht= Vehicle elapsed time input Pin F Dk Grn = A/C on Pin G Dk Grn/Yel = Canister purge Pin H Red = ALDL Pin G from fuel pump relay
Buy the factory service manual, you'll need it throughout the swap. The PDF version is about 50 bucks, eBay usually has old hard copies of the manual. Whatever you do don't buy the cheap Chilton's or Haynes manuals, you need the genuine gm publication.
This is the best advice you will get on doing this. I will add that the actual paper book is much more useful because of the fold out schematics.
I've already done an LS swap on an 84. I also threw in a 4l80e. If I were you I wouldn't touch that old factory harness. Pull it out and get rid of it. Pull out the digital dash and sell it. With the money you will make doing that you could buy a nice set of aftermarket gauges from any company you choose. Then get a nice aftermarket ECU to run the LQ9 and whatever transmission you want. I went with the Holley Terminator X and love it. Yes it will cost a little more. But what you gain in flexibility and tuning is well worth it.
For me the digital dash is part of what makes the early C4 special. And it does not need the ECU to work as it uses its own sensors. The only thing not working in the dash is MPG and range on tank.
I have an 4L80E and feed VSS data from my new ECU to the dash using a GPO.
I have a side project to reverse engineer MPG data from ECU to dash to make it work with an Arduino as translator from CAN data to 160 baud ALDL data used by the dash.
For me the digital dash is part of what makes the early C4 special. And it does not need the ECU to work as it uses its own sensors. The only thing not working in the dash is MPG and range on tank.
I have an 4L80E and feed VSS data from my new ECU to the dash using a GPO.
I have a side project to reverse engineer MPG data from ECU to dash to make it work with an Arduino as translator from CAN data to 160 baud ALDL data used by the dash.
It would be awesome to use an Arduino for mpg on the dash. I have a Nano running my cooling fans off of a LS temp sensor in the head. That way it freed up a output from the Holley. If you wanted to keep the factory dash and mpg that's a good idea. To each there own. To me I couldn't get that digital dash out of the car fast enough.
GoBy - Thx for the schematics - I think I'm set now.
Phobos84 - I was contacted by a member of this forum who is going to sell me a manual.
I already removed the engine harness and it's in the garbage. I plan on relocating the battery and using the battery tray area to mount the PCM and relay block to control fans/fuel pump etc. I do a lot of LS swaps and I make my own new standalone harnesses. I'll be using DBW with a Gen 3 PCM. As far as the gauges go, I might try and incorporate 2 new screens driven by a Raspberry Pi or I might go old school analog.
I'm currently working on another swap that I'm using Arduinos for data acquisition from the driveline, chassis and the air ride suspension that then talk to a Raspberry Pi. The Pi can control 2 screens, 1 for the instruments and the other for air ride suspension. (It still a work in progress)
GoBy - Thx for the schematics - I think I'm set now.
Phobos84 - I was contacted by a member of this forum who is going to sell me a manual.
I already removed the engine harness and it's in the garbage. I plan on relocating the battery and using the battery tray area to mount the PCM and relay block to control fans/fuel pump etc. I do a lot of LS swaps and I make my own new standalone harnesses. I'll be using DBW with a Gen 3 PCM. As far as the gauges go, I might try and incorporate 2 new screens driven by a Raspberry Pi or I might go old school analog.
I'm currently working on another swap that I'm using Arduinos for data acquisition from the driveline, chassis and the air ride suspension that then talk to a Raspberry Pi. The Pi can control 2 screens, 1 for the instruments and the other for air ride suspension. (It still a work in progress)
I love Raspberry Pi's but I hate going back and forth between a Pi and an Arduino on a project. Going from Python to C++ just makes my head hurt
I love Raspberry Pi's but I hate going back and forth between a Pi and an Arduino on a project. Going from Python to C++ just makes my head hurt
Good luck man. Sounds like an awesome project.
I'm not going to take credit for all the work involved in the programming. I started programming many years ago on languages like Cobol(on punch cards, that's showing my age), Fortran and Assembler. But I have a great young guy who's doing the coding for me while I focus on the hardware and the designing the PCB's for all this stuff. I just don't seem to have the patience for programming anymore.
I'm not going to take credit for all the work involved in the programming. I started programming many years ago on languages like Cobol(on punch cards, that's showing my age), Fortran and Assembler. But I have a great young guy who's doing the coding for me while I focus on the hardware and the designing the PCB's for all this stuff. I just don't seem to have the patience for programming anymore.
Unfortunately I can't get away from it. I teach programming of industrial controllers and PLC's for a living. So I'm kind of stuck programming.
I was able to get a copy of the FSM including the Supplement for the '84. I've verified all the circuits but there still is one wire on C455 - Pin L - Red Wire - that I can't seem to find in the schematics.
Does anyone have any ideas?
I plan on documenting this build and when I get further down the road, I'll post the changes and the revised schematic.
This is from the wiring diagrams and most seem to match. If you've the connector in hand it should be easy I'd think. Most match. RED - L = Circuit 458? Try page 922 (top edge) of the .pdf FSM.
Need Wiring Info For 84
