350z CAN-Bus system info

[midnightracer]

Hey guys, I have been floating around this forum for some time now, and decided to finally make a post. I have read over the 350z fsm, been on wikipedia, and every where else to try to learn as much as I can about the new CAN-bus systems that are in the 350z.

If anyone knows anything about this system, and the functions of it in the 350z please let me know. I am looking at doing a motor swap, and I need to know what kind of an obstacle this system creates. I know there are several people that have swapped 2jz engines into the Z, and a couple VQs into s13 and s14 chassis, but its still unclear to me about how this system is connected in the harness, and to the ECU, if it is at all.

Basically I am completely lost at this point, and if any one knows anything, please post it here. Especially those who have done the swaps

Thanks

(Also, I have searched all over this forum and have not found a clear thread topic about this, but if there is please let me know. I'm not trying to make a redundant thread.)

[R350Zz33]

there are some wire harness companys out there u tell them ur car what componets u have engine and they can make a wire harness for it including ecu and all that good stuff

[midnightracer]

Well, I will be using the ecu and wiring harness from the motor, and adapting it to the current wiring in my Z. I do not want to go standalone. Unfortunately, because of the CAN-bus system in the Z, its not as simple as just doing mounts and a little harness adaptation like in an earlier model Z. So, I really need to find out exactly what the CAN is used for in the Z, and what needs to be done to work around it. I know that a standalone is not required for this motor swap.

[midnightracer]

So nobody knows anything about this?

[rmezz13]

i have no clue, and i am a little shocked that a moderator hasn't popped in with the answer.... try contacting a nissan shop, or a motorsports/performance shop that is familiar with the swap you are trying to complete...... sorry i can't really help, all i can do is point!

[midnightracer]

Actually, that is a lot of help. I didn't even think to call a nissan shop or tech somewhere. I figured someone had to know on here, but the lack of responses seems to show otherwise. I'll see what I can find out and then post it up here.

[rmezz13]

I appreciate that you'll post it, thus furthering our knowledge! I personally learn something new everyday on here, and what your talking about i've never heard of so i am interested to know whats up. If i ever get any money a 2jz swap would be nice.

[bonafyed89]

Hello, hopefully I can give you some insight on what one of the CAN system does. Basically the CAN system (Controller Area Network) is a simple highway for information between modules, it uses two wires wrapped together and lets the modules communicate to one another.

before the 1980's cars were sharing multiple sensors and each one required its own separate circuit so there were a lot of wires. Sensor current load was also being increased because the sensor was used for more than one module to get the same similar information.

So now with multiplexing this allows a module to directly monitor a switch or a sensor and share the information with other modules. Decreasing the amount of duplicate sensors and complex wiring.

Multiplexing (or MUX) means sending more than one piece of information over a single circuit. Single circuit as in two wires.

Now for the swap, I'm assuming that most of the engine controllers will be replaced. to get the 2jz to run, PCM, TCM, ECU etc. I'm not familiar with the swap or the 350Z for that matter.

Some cars will use a module like the BCM ( body control module) as a hub like a computer would, where it gets the information from the modules and relays it to the other ones. Im not sure how the Z would react to not seeing some of the modules. I tried to post a crappy drawing on here but I failed.

Like the poster above side, figure out what is really involved to make it run with the most factory parts, because putting an engine in any car is simple but to make it work with electronics that are many years newer... why not just turbo the Z? Seems more cost effective and easier in the end.
Modified by bonafyed89 at 9:19 PM 5/13/2008

[rmezz13]

I suppose the swap is intended for the reliability of the 2jz on high power with stock internals???? Thats what i would want it for, very reliable even with over 700hp on the stock internals. Probably the best import motor ever made....

[midnightracer]

Thanks bonafyed89 for that info. I am actually not planning on doing a 2jz, because although it is a good motor, its a toyota and does not belong under the hood of a nissan. The 2jz was merely an example because I have see it done a couple times now. I am actually going to put a vh45 in it. The reason for doing this over turboing the vq is the fact that the vq cannot handle good power in stock form. So after, spending tons of money on a turbo kit, one must also give an arm and a leg to build the motor. After all of this you still would not have the smooth, broad powerband of the vh45. You can pick a vh45 up for about $1k and if your heart so desires throw a couple turbos on there since it comes factory with a forged crank and rods.

Because this engine is a popular swap for 240sx and 300zx owners already, there should be more aftermarket parts released for them in the near future. Possibly making this a more popular swap in the Z/G cars as well. I know Tecni is already working on swapping a vh45 into his g35, but I have not gotten a response to how it will be managed or wired.

I have spent a lot of time the past few days reading through the 350z fsm, and believe that I have come up with some very good information. First off, everything is controlled by the computers. The gauges, the lights, the windows, seats, a/c, wipers, etc. These computers include the BCM, IPDM E/R, A/C Amp, and several more, and they all communicate with each other using the CAN Bus system that runs throughout the car. It seems that in doing a motor swap, all one would have to do is keep the current ecu in the vehicle, and send it the crank position, and cam position information. That way the tach would work. Speed is picked up from the wheel sensors that go through that ABS/TCS module. If you use the factory TB and accel pedal you should be able to still have cruise control. I just need to find out how most people run aftermarket fuel systems in their Z, and how the computer deals with that. I want to be able to use the computer for the fuel gauge oly, and have a completely separate fuel system. I guess thats the best way to do it.

Other than that, it just seems that I will need to find a way to trick the factory ECU into thinking that it is actually running an engine so that it will allow everything else to work. Systems like the A/C require the ECU to think the throttle is being pressed. So its just the little things now I have to figure out. As far as I can tell though, if I run 2 ECUs in this swap, all should go well. Please let me know if any of this is incorrect.

Again, if anyone has done an engine swap into a Z or G, any help would be much appreciated. I plan on posting the swap progress as soon as I have all the information I need to start the project.