Wiring question?
 

I was just reading into canbus stuff because I’m LS swapping my brz. It seems like a huge headache.

I had planned to run both the brz oem computers to control all factory stuff like lights ac abs ps windows all that good stuff and I was going to run the ls oem ecu with a stand alone harness to run the engine stuff. I know I would have to do something special to get the factory gauges working but that’s all I thought?

to run AC and Cruise Control right now your option is to go PureAutomotive Motec & pnp harness.

Colin @ MRS electronics is working on getting it to work with with our cars via his canbus module, using my car as a development mule, but I cant speak to when or if it'll work.

If youre still going the canbus module route, get a stand alone LS harness, from something like SpearTech or WiringSpecialities, then see my post #51 here for some wiring help: http://www.ft86club.com/forums/showt...=128216&page=2

Good luck.

I don’t understand how that won’t work? Why can’t I have the factory car stuff ran from it’s own computer like the signals lights radio and all of that and just use the ls ecu with its own harness to run the engine and anything else motor related?

Also I need to get my cars oem computer programmed because I replaced security stuff and it doesn’t start right now. If I HAVE to ditch the stock unit should I just forget that? Because the Toyota dealer in my town said they can’t reprogram it and Subaru dealer is a few towns over.

Standalone + MRS is usually dual ecu setup :lol:


1. The factory Subaru computer will handle most everything OUTSIDE of the engine-- BUT AC and cruise control are controlled by the GM or aftermarket ECU is controlling the engine because -- for AC it'll need to activate the fans and increase idle speed -- and Cruise will need to modulate the throttle. So that needs to be communicated by some more intricate canbus work than is currently available (again being worked on by MRS electronics- but no guarantees from me) or a new, more capable ECU (IE Motec).

2. You do not need to have the subaru ECU reprogrammed to my knowledge. I did not need to with my stand-alone setup with my FRS.

The factory dash communicates with the engine via Canbus. The canbus communications are used throughout the car systems (ABS, PS, CC, Dash, etc..) in order to report accurate information (basically to work). Furthermore, some of those systems use engine sensors communicating via canbus to work. Because of this, this is not a swap like it happened in the past, where you could just control the engine apart from the car systems and they would just work. The canbus system needs some integration between both parts. This is where a canbus translator or standalone ECU is required to get these systems to function properly.

Yes, some stuff works aside from canbus integration. But CC, PS, Dash, AC, ABS, among others, all need canbus communication to function.

If you go standalone, you won't need the factory ECU at all. I don't know if MRS canbus passes through the security information from the stock ECU or if you can also disregard it, but with the MRS canbus you do need the factory ECU plugged in.

Basically I just want the push to start to work, the AC and ABS to work. The dash to work. Couldn’t care less about cruise or anything else

That's pretty much everything unfortunately. ABS module, body control module, keyless module, ecu (or a standalone that is talking the right canbus language), cluster all have to be talking and happy for everything to work and not error out.

Do you guys know any shops that have done a complete rewire to remove the can bus system?
I'm looking to keep power windows door locks, and lights. Power steering may be handled with a module and stock motor or aftermarket electric power steering.
I will just run a custom harness and a GM ecu for the engine.

I want to use a power distribution module to eliminate the fuse blocks and relays as well. Gain some room loose some weight.

our racecar has nothing but a custom harness and a motec pdm/keypad in it. none of the things you are looking for still work or are installed though.

Thanks for the reply. Looks like I may be on my own going this route.

Since you got push start it will get a bit more complicated. I think MRS controller passes though security stuff though canbus so the use of the factory ecu will be needed for push start. IF you want everything to work go with the motec option.

If you want important creature formorts to work use MRS. But not sure if he has AC working. He has support for push start. but you need to keep your factory ECU.

Im removing so many components. I think it's better to do a complete rewire on the car.

thats what we did on our green car. much nicer in the end

How are people wiring up there stock fuel pump? I have the stock fuel pump with the wires cut and spliced bypassing the fuel pump controller. Im using the brz ecu and the ls ecu. I did a simple wire harness set up with a couple of relays and wires for 12volt constant 12volt keyed, and 12 volt for the fuel pump from a relay. Ive been going over the wiring and i only see a 20a fuse but no relay in the fuse box? Am i just putting that 12volt feed to one end of the fuse?

I did the same bypass, left the OEM ecu to power the fuel pump via the original relays and wiring.

Thank you again sir that makes sense. The wiring diagrams for fueling system on the brz are tough to follow. So basically I can eliminate that relay and I don't need the signal from ls ecu at all for fuel pump. I'm about to wire up a couple relays for the fans (stock currently because budget) or is there an easy fix using stock relays in fuse box? I notice there are 3 relays on the diagram and read else were they are a little weird.

I think I'm reading you right. just to clarify, you can eliminate the fuel pump relays from the LS side of the harness if they're included. not the oem side. the bypass still uses the oem relay to turn pump on and off, it just removes the OEM computer's control to reduce power.

you need the LS harness to control the fans, either running a wire(or two) into the fusebox to trigger the OEM relays, or by a separate relay and to the fans.

Here's a couple of pics so far. Modded the old gto alternator wiring into the brz spot for the alternator in the fuse box and the white wire as well as hooking up the brown wire to a 194 then to an ignition on source tbd. I went over the diagrams and it does seem simple enough to use the BRZs relays looks like fan. 1 signal triggers 2 of the 3 relays and fan 2 signal does the other. There is a pic of the fuel pump controller wires I cut and soldered. Other then that just looking at best place in the fuse box to get the switched power from.

I was also thinking of ditching all the OEM wiring and just running the basics and a few little features (windows, heated seats, lights, door locks, head unit, HVAC) the only im not sure of is the blower motor and the HVAC controls need the rest of the can bus systems to operate or can I just deepin most the harness out and leave the hvac system to itself and feed it 12v

I will be finding out. In reality everything should work on 12 volts dc. It's just a matter of looking at the wiring diagram, and figuring out how to rewire without the can bus system controlling each device with a low voltage signal, Or removing the factory can bus system, and putting in your own can bus controler. Power steering and ABS would be the most difficult I would think. They are not simple on off devices.
I'm not keeping the stock abs, and I don't mind going with a different electric power steering unit.
I'm hoping someone starts down this path before I do. If not it's going to be a pain in the ass.

I think next winter I'll be tackling this,... and I think you're right about the power steering at the moment I have mine working without canbus but it cuts out randomly sometimes... I have deleted my abs completely in the engine bay since theres not really a need for it as its not a winter car and I don't plan on pressing as hard as I can on the brakes while I turn lol for everything else should be pretty simple other than HVAC...

It would be nice to get rid of all the other stuff and all the different box's! have you seen the wiring diagram its crazy how many sub systems there are.

I was also thinking of getting an aftermarket keyless system that can replace the stock can bus/ antitheft system computers

Yeah I have the wireing diagram saved to my drive. Lots of sub systems. Not sure what I'm doing for anti theft yet. I will be starting on getting the engine in, and wiring it up within a couple of months. Working too much to get anything done right now.

Little late to the party but is your push to start aftermarket? That should be running a bypass module already so it shouldn't give you trouble with the stock security systems. I think the MRS module is supposed to cover "most" of the other stuff. Now if you went with a standalone, the Nemesis is supposed to retain all functionality EXCEPT cruise control.

How are people wiring up after market gauges for water temp. More specifically using a brz/frs sensor in the system some where and an aftermarket or an ls sensor and aftermarket? I'm still sorting a canbus solution out as well.

LS water temp sensor is on the driver side head or close to it IIRC. If you want an aftermarket one for a gauge you'll need to put it in the coolant line somehow. That'll depend on what kind of hoses you are using. It'll boil down to some kind of splice/interruption in the hose with a sensor port in it. Maybe there is a thermostat housing with a sensor port?

PS, there may be a plug in the engine somewhere that can be replaced with a sensor that I'm unaware of.

OEM temp gauge working here via MRS device canbus translator.

OEM 86 sensor correct? Where did you add yours in. Mrs said they don't have a unit for an ls1 unfortunately but trying to find an alternative. I would attempt adruino but I need a new home computer or laptop so i would be dropping a few hundred either way.

No, factory LS sensor, to the factory GM ECU. MRS Canbus translating the temp signal to gauges from GM ecu.

What are you trying to accomplish? Operate the factory temp gauge or an aftermarket gauge that will show exact numbers?

Aftermarket for better numbers and stock sensor to trigger fans. I'm using OEM relays. Unless I'm looking at it wrong.

Aftermarket, just get a port in there somewhere and plug that shit in. No sweat. For OEM gauge, just use whichever works with your computer choice. Probably the stock LS sensor

Thanks I have a way of over complicating in my head sometimes.

Same. If you check the classifieds you might find some gauges for a good price

Fuel pump controller bypass wiring setup
 

Hello, I am in the process in getting the Radium's dual pump hanger with their two relays kit. I'm dubious on how to connect all this correct.


Can any of you guys could help wire the signal wires and the power wires?

I doubt that saying that a standalone is installed but, if it does then it is.


Thank you

Not sure on if your computer is switching positive or negative. Let's assume it's positive: signal+goes to computer, ground is ground, load1 should go to a power source like the battery or distribution block, load 2 goes to the pump, then the pump needs grounded. Or you could run +straight to the pump and break the ground with the relay. If it's not clear which pin is which on the relay, look online for a diagram with that many pins. Relay numbering should be standard. These aren't Radium specific relays

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