Whats This Brow Box For?

[jedi134]

Hi I was just wondering what this brown ecu type box does? is it the ECU? If it is there arn`t many wires coming off it for an ECU.

The black arrow marks the box I mean, should have done it in red I know but hey!!!!!! :P

[chatman]

Hi I was just wondering what this brown ecu type box does? is it the ECU? If it is there arn`t many wires coming off it for an ECU.

The black arrow marks the box I mean, should have done it in red I know but hey!!!!!! :P

HEY :o :o :o :o that's my RAV...............

It also has the words DENSO on the top of the brown box....

[shcm]

It's the EDU (Electronic Drive Unit). Essentially it is the final drive to the injectors.

It's connected to the engine management (EMS) ECU. The EMS ECU will send timing signals to it and the EDU will produce the higher current injector drive signals.

It's perhaps an odd arrangement. I've not worked on any EMS designs for a few years, but the ones I have, did have everything in one box.

Having said that, we did have designs where the processor/signal processing (brains) were on a separate PCB (printed circuit board) to the "power" driving transistors (for injectors/ign coils etc), but it still all went in one box.

I suppose with this arrangement half the electronics are in cab, where usually the temperature spec is lower (and therefore it's possibly cheaper and maybe slightly more reliable) and less is under bonnet. If I remember correctly the 4.2 ECU is in cab. The whole system may not work out cheaper though.

The 4.3 however has both under bonnet, so you do question why it has been separated. Maybe it allows for different spec injectors by just changing the EDU and keeping the physical ECU as a common part across vehicles, with just a tune change.

The other thing to consider is that connectors and harnesses are very often a bigger problem in the reliability stakes, so if you can reduce the number of them, so much the better. The EDU/ECU arrangement probably doesn't minimise the the number of connectors, but then I haven't looked at it in depth.

All pure (and probably flawed) speculation based on years of ECU design/development personal experience.

Cheers

[jedi134]

Chatman it could well be your car as I borrowed the picture to show the brown box and yes It does have Denso and maybe Toyota on it, I hope you don`t mind me posting the picture. If this is your car did you have any ECU/Injector work done on it, and did this box appear after it? I know some older Rav`s with the DMF problems had ECU work done, I presume to limit the torque which may have been eating up DMF`s? Someone correct me if I’m wrong.

shcm do you think this could be some kind of after sales fix to rectify some kind of know problem with these diesel engines? Or is it standard and OEM. It would be good to know if any other 4.2 diesel Rav owners have this EDU installed.

So I presume the EDU is like a solid state type of fast switching relay solely for pulsing the injectors on & off.???

"All pure (and probably flawed) speculation based on years of ECU design/development personal experience." All sounds feasible to me. :D

[shcm]

shcm do you think this could be some kind of after sales fix to rectify some kind of know problem with these diesel engines? Or is it standard and OEM. It would be good to know if any other 4.2 diesel Rav owners have this EDU installed.

It's standard OEM. Will have been there from new.

So I presume the EDU is like a solid state type of fast switching relay solely for pulsing the injectors on & off.???

Yeah exactly! For a simplified explanation - It will be power transistors effectively configured as switches, with some other protection circuitry around them, to stop the injectors destroying the transistors when they turn off. Relays would be too slow and limited life in this application.

[chatman]

Chatman it could well be your car as I borrowed the picture to show the brown box and yes It does have Denso and maybe Toyota on it, I hope you don`t mind me posting the picture. If this is your car did you have any ECU/Injector work done on it, and did this box appear after it? I know some older Rav`s with the DMF problems had ECU work done, I presume to limit the torque which may have been eating up DMF`s? Someone correct me if I’m wrong.

No problem using my RAV pictures.....

As Shcm say's the box was there from new..... I have had injector work done and the DMF & Clutch replaced..... but no ECU work carried out to my knowledge....

[bothwell_buyer]

sad news judging from the pic - this is an aftermarket engine swap, tarted up to look like a Toyota engine. It is actually a Massey ferguson 3 cylinder diesel engine, stroked and running backwards. :P :P

[jedi134]

Chatman it could well be your car as I borrowed the picture to show the brown box and yes It does have Denso and maybe Toyota on it, I hope you don`t mind me posting the picture. If this is your car did you have any ECU/Injector work done on it, and did this box appear after it? I know some older Rav`s with the DMF problems had ECU work done, I presume to limit the torque which may have been eating up DMF`s? Someone correct me if I’m wrong.

No problem using my RAV pictures.....

As Shcm say's the box was there from new..... I have had injector work done and the DMF & Clutch replaced..... but no ECU work carried out to my knowledge....

Do you know exactly what they did with the injectors? and why they did it? did you have runing problems?

[chatman]

Do you know exactly what they did with the injectors? and why they did it? did you have runing problems?

My High Pressure Fuel Pump went...Leaving the RAV powerless and sluggish. I got it re-conditioned and also changed all the fuel lines as as-well as an air leak was causing the RAV to not work....Stranding me and my family miles from home :crybaby: ...But all sorted now....

Bothy...I have this engine awaiting to be fitted into the RAV :D :D :D Should be a nice straight swop..... :rolleyes:

If this fails I'll fit this one....

It's been road tested :) :) :)

[bothwell_buyer]

haha

You'll pick up the JCB engine for £89.99 at the auctions next week! The ferrari engine is the wrong colour - you'll need to resray the car! :lol: