[Graham2018]

I am converting a BMW Mini Clubman to electric drive with an AC induction motor and Curtis 1238-6501 controller.

The donor car has electric power steering / ABS etc which need road speed and engine speed on CAN BUS to opperate. As the engine is removed, I have lost the signal and the power steering no longer functions. The ebay modules for electric power steering fixes do no work.

I therefore need to recreate the mod bus signals. Is there anyone who has done this before? I have read that you can hack the CAN BUS, but I have no programming knowledge to attempt this. Can the original crank speed sensor be used??

Thanks
Graham2018

 

[brian_]

Can the original crank speed sensor be used??

The crank speed sensor will feed an engine ECU, which you will not have any more, so that sensor doesn't matter. Whatever you get to transmit an "engine speed" on CAN (presumably some programmable box with a CAN interface) does need an input (unless it always generates a fixed speed), but it doesn't matter whether or not the sensor is similar to that used with the engine.

Also, wouldn't the motor controller produce a motor speed signal of some sort? And more importantly, what do you want the "engine speed" to be, to get the desired vehicle behaviour?

 

[Graham2018]

Thank you Brian.

I have next to know knowledge of can bus. I have asked Curtis Controllers for details of the can bus, but have not had a reply.

I am not sure if the signal from the crank shaft sensor (or a replacement input) is sufficient to allow the ECU to believe the engine is running, and therefore activate the electric power steering and ABS.

I have yet to take the engine out of the donor car, and therefore I have checked the operation of the power steering. After cranking stops and the engine is up to idle speed the steering kicks in. This may be a time delay, or the ECU may be getting a signal from somewhere else to activate to power steering.

The local mechanics don't have any idea about this, they don't normally get these types of questions!

I am inclined to avoid communication on can bus as I would need a lot of support. If I can use the original speed sensor pick-ups and remount them to pick up the motor shaft speed, I believe it would be easier for me.

An further suggestions would be appreciated.

Thank you
Graham

 

[jbman]

The Mini Cooper power steering pump does not require the ECU to function. I am using one with the rack and pinion conversion in my ‘66 Mustang. If I recall correctly, the large wires go to 12v + and -, and the small yellow wire activates the pump when it sees 12v. The pump is self-controlling at that point. I have the big wires switched by a 100 amp relay, and the small wire gets power through an oil pressure switch so I don’t drain the battery. I’d just hook the sense wire up to 12v keyed power with a switch to turn it off manually.

That thing draws A LOT of amps, though. Especially at startup or when the wheel is turned against the lock.

I can double check for you tomorrow if you’d like. It was a pain in the butt to figure out, since I don’t see a lot of people using this pump.


Sent from my iPhone using Tapatalk

 

[brian_]

I'll wildly guess that at Clubman is mechanically the same as a Hatch. Now, what type of steering is this? The original post says electric power steering, which means an electric motor is mounted on the rack or the column. An electric pump would make it an electro-hydraulic system: the rack itself is hydraulic, and the pump is electrically powered (instead of being driven by the engine). The details matter, because they have different control hardware.

After a quick web search, it appears that the steering assist was electro-hydraulic up to 2006, or maybe 2011, then electric (it looks like it might be a motor on the rack at the column base) after that. What year is the donor Clubman? I'll assume pre-2007, so it's electro-hydraulic.

Some electro-hydraulic steering pumps require CAN communication to operate, which is the subject of various discussions in this forum. Some only need power to the right input pin, so wiring it appropriately as jbman describes is all you need. It looks like you're lucky! (Except that Mini pumps are notoriously unreliable).

Of course this just gives you a constant level of boost. Modern steering assist systems normally vary assist with road speed and steering angle, which is what all that computer communication and wiring is for. A later enhancement might be to restore this level of functionality, once you have a handle on the CAN situation.

 

[Graham2018]

I don't believe there is any difference between the hatch and the clubman, I bought the clubman as it is 10 inches longer to give more room for the batteries, the wheel base is also longer which will avoid having weight behind the back wheels.

I deliberately bought newer than 2007, as up to 2007 the power steering is electro hydraulic, and I had heard that these are less efficient. The 2008 model is electric motor assist only. I have the heavy power supply leads attached and 12v on the yellow ignition supply. This has not worked.

I have checked, and when the ignition is on without the engine started, there is a 12v feed to the yellow supply. I have found that the power sterering is activated about 2 seconds after crank termination, and the engine is up to idle speed.

At the moment this is a bit of a frustration as I am really keen to get on with it. I am currently driving a 21 year old Skoda Favorit ELMO, the controller motor and battery are about 3 years old. The body rust is to far gone to make it viable to carry on, and therefore I need to retire it and strip it.

I appreciate your support.

 

[jbman]

I don't believe there is any difference between the hatch and the clubman, I bought the clubman as it is 10 inches longer to give more room for the batteries, the wheel base is also longer which will avoid having weight behind the back wheels.

I deliberately bought newer than 2007, as up to 2007 the power steering is electro hydraulic, and I had heard that these are less efficient. The 2008 model is electric motor assist only. I have the heavy power supply leads attached and 12v on the yellow ignition supply. This has not worked.

I have checked, and when the ignition is on without the engine started, there is a 12v feed to the yellow supply. I have found that the power sterering is activated about 2 seconds after crank termination, and the engine is up to idle speed.

At the moment this is a bit of a frustration as I am really keen to get on with it. I am currently driving a 21 year old Skoda Favorit ELMO, the controller motor and battery are about 3 years old. The body rust is to far gone to make it viable to carry on, and therefore I need to retire it and strip it.

I appreciate your support.

Ah, I did not realize they switched to a fully electric system in 2007. I know there are some modules on eBay that will drive an EPAS motor. I believe those also have a failsafe mode where it automatically applies moderate assist if it loses communication with the ECU

 

[Graham2018]

You are right there are a few on ebay. However they are specific to a few vehicles that can easily be fitted with the mod. I have inquired, and they have all come back and said that they won't work with the MINI EPS.

I have considered taking an ECU off a rack that can be controlled, but the later mini has a fully enclosed unit without which cannot be separated.

 

[brian_]

Okay, my assumption was wrong, but that's the reason to state assumptions explicitly: so they can be corrected!

You need to know exactly what is plugged into the power steering unit, and what signals are expected. I would look at the factory manual's wiring diagram and troubleshooting information for that. I bought the factory manual for my first car and a later old car, and aftermarket manuals for one after that, but I realize that not many people get paper manuals any more. For more recent vehicles I have purchased online access; that's available from some manufacturers, and from third-party sources (I used ALLDATAdiy.com). Do you have a source of technical details?