Steering, Suspension, & Brakes

All I have for reference at this time is the MG-Roadmaster which we converted using Mikes column with the Venza gearbox (I think but I could be wrong) and the Bruno knob controller.It has very good feel and transforms the car. Return to center is not as brisk as without it because the gearbox does have some drag. I think they all will, as you have to spin the assist motor through a worm and pinion gearset which I suspect has around a 5:1 ratio. So it cuts down on the suspension's ability to smartly whip the steering wheel back to center. This will also be affected by the width of tires that you use as a wider tire creates more jacking action and will require more steering effort, therefore will return to center more forcibly. But it's a good sort of compromise to make. I wouldn't say the EPS has no return to center, just not as much as you are accustomed to in the car.

Jim

My car goes under the knife tomorrow, wish me luck.

Jim

What are you cutting?

There is a brace behind the dashboard that is welded to the square tube that runs across the cowl area and bolted into the shelf from the bottom and stabilizes the original steering column. For the EPS that brace has to come out as it is in the way of the gearbox and motor.

On the Roadmaster I was able to leave a small bit of it in place, which also supports the odometer reset cable. On my car the odometer reset is a push button on the face of the instrument so I was able to get rid of that knob and cable, and I will be making a bracket that bolts into the shelf to support the EPS. Kinda hard to visualize without looking at it.

At least, I think it is welded. I found one on ebay:
[www.ebay.com]

and it looks like that one was bolted in. So it'll be a journey of discovery.

Jim

They are definitely bolted in Jim. I've had mine out before.



Edited 1 time(s). Last edit at 05/26/2018 11:06PM by rficalora.

Thanks Rob, good to know. It'll be much easier to trim if I can pull it out.

Jim

Hi guys,

I just finished installing a 2010 Toyota Corolla EPS. I had the Saturn Vue EPS in the car but hated the lack of self centering, plus I had an electrical issue associated with remotely locating the EPS unit.

When I power up the EPS, it turns the steering column continuously to the left (it doesn't stop). The wiring is super simple (12V ignition on, power from battery, ground), so I am at a bit of a loss. Any ideas what it might be?

I may try to track down a spare EPS ECU to see if it's the module.

Thanks in advance for any assistance.

Chris

Chris, I may have the exact same unit, 2009 Corolla. I powered it up on the bench and it worked as it should. Did you have the feedback sensor out of it? I imagine if you removed the 3 bolt flange for machining you had to. The plastic block has a nub that sticks out, should prevent installing it backwards. I'd check that first.

Jim

Can you post a photo of your install?



Edited 1 time(s). Last edit at 05/27/2018 04:42PM by BlownMGB-V8.

Thanks Jim. I will check that out.

I'll take a photo when I get the column back in the car.

Here is the bracket that needs to be modified for the EPS. I made those cuts to remove it from around a speaker wire that was threaded through the big hole. About 6 bolts holding it in, not easy but if you remove the speedo and defrost hose there is room.



Here it is after modifications. This gives room for the EPS gearbox to tuck up into place. If you are concerned about loss of strength you can add a bracket to the rear of the EPS to mate up to the shelf legs, that is what I'll be doing as I used the Toyota intermediate shaft.



This is the same mod needed with the complete EPS unit that Mike sells, but with careful trimming you can keep the section front-to-rear that supports the speedo reset knob. That's what we did on the Roadmaster. You can trim closer of course.

Jim



Edited 1 time(s). Last edit at 05/28/2018 12:18PM by BlownMGB-V8.

Jim, are you referring to the sensor ring that goes around the shaft? If yes, it is in correctly based on photos I found online.

It's sounding like I might need to do a torque sensor zero point calibration. But you need a Toyota handheld tester for that and it needs to be plugged into an actual Toyota, not just a Toyota EPS ECU!

AAARRGH.

That is the sensor.

I'm not sure what you have going on with a tester. On mine I just got the gearbox and module out of the same car, didn't cut any wires between the motor and module so that all plugged back in the same way it came apart. That left me with the two heavy power leads of which the blue was hot, plus a very small blue wire that hooks to the ignition power, and the twisted pair which I didn't hook to anything. I think that gets a signal from the PCM to control assist level based on speed.

It worked on the bench when I tested it. I did not retest after removing and reinstalling the sensor ring you mentioned. That should happen today maybe. I will try to get a photo of it for you. I do remember it could not be bolted in backwards unless that small nub on one side was trimmed off.

So if all that is right and it drives in one direction I'd guess either something is damaged or out of calibration. You might try shifting the sensor ring around to see if its position makes a difference. I suspect that could be something that is tuned out with the calibration but there is a little bit of slop in the mounting position and it could be critical. Worth a try. A mechanical adjustment would be easier than all that messing around with calibration equipment.

Jim

So here is the sensor Chris, check to see if it isn't the same one you have and oriented in the same direction.



I think I may have to do the same thing if the adjustment is that critical, I should know more later today, I'm hooking up the wires now. If so, my plan is to disconnect the intermediate shaft so there is no stop, loosen the screws, and see if I can shift the sensor and stop the rotation then cinch it down.

This is all purely theoretical of course. I may not have to do anything, and it may not help you at all. But other than swapping it all out for one that has tested good on the bench it's all I can think of to do. Even then if disassembly and reassembly throws it out of calibration... well that could be a real problem since you just about have to remove the input tube and turn it to match the upper column tube. At least that's the easiest way, no doubt there is another solution.

But for all of you out there watching, do yourself a favor and call Mike. You'll be about a day changing over. I don't think I'd be willing to go through all of this for somebody else's car and I'm not sure I'd do it again on my own. For sure it'd cost quite a bit more than Mike is asking.

Jim

Thanks Jim,

It's not out of the same car so it could be a calibration issue. Jim N wonders if I assembled the two pieces 180 degrees in the wrong direction. Now to try to find time to get to the shop and bench test it!

I'm also grabbing an entire system from another corolla to try it.

If the module and gearbox are out of different cars I'd suspect that as the problem. These things might be a bit sensitive about centering, and the parts may have to be a matched set. Since you're getting spare parts, hopefully that is the only issue and the matched parts will cure it.

Jim

OK, good news Chris (at least I think so). I wired up power and jumpered the small blue wire to +, relays clicked on in the module and the steering wheel sat dead still. I moved it and turned the wheels, maybe a little stiffer than I'd wish for but the wheels are off the ground so I won't get a full test until later. Anyway this does go to the issue you are fighting. My best guess is a module mismatch. Might even be possible the feedback wires are switched in some applications.

Good Luck!

Jim

Thanks Jim.

I'm hoping I can use the casing I have now (it's been modified to fit the column) but switch out the sensor ring and EPS from the new system I'm getting tomorrow. That should work right?

Seems to me like it should. You definitely have something amiss with that system you have and it does sound like a backwards sensor but that could only happen if that nub was trimmed off or the wires are reversed. You'll have enough parts to fix it, even if all you use off the old one is the column flange.

So, road test report then. Got everything buttoned up and went for a test drive. First off, it takes 3-4 seconds to initialize once the key is on, so give it time. Maybe start the car before doing up your seat belt. Next, the assist with no input signal is quite acceptable and very nice to have. Thirdly, the return to center is there, but nowhere near as snappy as with manual steering. Not even close. In fact you will probably sometimes find yourself helping it, especially if you have anywhere near stock width and offset on your tires. Mine are not and it does come back to center, but the suspension has to back-drive the assist motor through the gearbox. I find it quite acceptable but that is my personal impression.

Tomorrow I plan to do back-to-back comparisons between this and the system in the MG-Roadmaster. Just my impressions, I'm not doing any measurement or extensive testing. I just want a feel of how they compare, since both cars are currently here.

Jim

The sensor isn't in backwards. I think the issue is with a miss-matched ECU/EPS. Since I don't have the OBD connector plug, I can't recalibrate the ECU.

The things you learn in hindsight....

I'm grabbing the OBD connector with the new EPS/ECU tomorrow so hopefully that will solve my issues.

My short drive with the system already confirmed that the Toyota EPS is superior to the Saturn Vue (self centering is awesome) but it would be nice to be able to set the level of assist.

Chris

I did the comparison test drives this morning. First, I do not know what gearbox Mike uses. It may be the Toyota Yaris, I think that is the most likely. Maybe Carl knows.

So first off, the turn-on, turn-off comparison was a little odd. Mike's unit came on in a little over 1 second and stayed on after key-off for about 3-1/2 seconds. That's what I would expect of normal operation. The Corolla unit took over 3 seconds to come on and powered off in less than a second. To me this suggests an RC circuit with a failing capacitor in the module I have. I will have to watch for a gradually increasing turn-on delay. Chris, please let me know what yours does if you will.

In terms of power they were very similar with the Bruno knob on Mike's unit set to about half scale, and that is where I have been driving it. In terms of self centering, also very similar. At anything over 1/8 turn they do have a reasonable level of return. Below that not very much at all.

Driving feel was very similar as well.

Jim