I posted the Vue stuff 2 years ago on Mustang, Falcon and FMF and it took off like wild fire! 

I had so much stuff to do on my Falcon, I did not bother with the EPS until now that I am ready for it.  Personally, I am not too crazy about  hooking up 3rd party box to the steering ECU.  A lot of time in research and development went in to the system.  I would rather have fail safe default mode for safety.

Below is the fail safe for Yaris as well.  As you can see, it does not care about CAN BUS.  If it does not see the engine ECU, the Amount of power assist is fixed for a speed of 43 mph (70 km/h).   Therefore both the Yaris and Prius "feels" the same.

Kevin, you should not have any issue with steering returning back to center when you come out of a turn do you?

The Saturn Vue EPS has this issue with the eBay box.

Waid

I signed up to this forum, just because of this thread. Waid, thanks again for posting all of this information and making it available to the world. That is exactly what hotrodding is all about.

Kevink, I really appreciate the information that you posted regarding the activation points of the 3 levels of assist with the Yaris non-ABS ECU. I was originally thinking that the level of assist is directly related to speed in a linear fashion, but clearly, your experimentation with the flashing LEDs has demonstrated otherwise.

A little about myself, I have a 1967 Cougar, with an unfortunate engine swap, T56 trans, blah...blah...blah...

I have a TCP manual steering rack, and even with the skinny front tires, the steering effort is very high. The engine is managed by a Holley Dominator ECU. One of the things that the Dominator can do is generate a square wave pulse based on vehicle speed. I currently have the T56 VSS sensor wired to the Dominator and it registers and displays (through a Holley 7" dash) accurate speed. Obviously, what I am hoping to do at this point is output a signal from the Dominator to the Yaris ECU and have variable levels of steering assist based on speed. From what I have been able to gather from various information sources is that this should be doable.

Again, thank you to everyone for supplying various bits of information. 

Andrew

It should work provided the square wave being generated is the proper polarty.

The Yarus ECU VSS pin when unconnected is pulled positive and is looking for pulse's to ground from the VSS (or my LED)

As long as you can provide negative going pulses it should work fine.

Let us know of your progress on this as we are still learning this unit, I love how mine works, makes the car so much easier to drive and no messy fulit leaks

Kevin,

Can you elaborate more on this please. Another option I have with the Dominator is creating a PWM output. This can be either PWM+ or PWM-. As I understand it, the PWM+ creates a positive square wave, while the PWM- creates a negative square wave pattern. I can configure this output with a table based on vehicle speed. In a previous post you mentioned a couple of critical values, those being 5, 45 and 75 pulses per second as being the threshold values for the three levels of assist. 

As I understand it, 5-44 PPS results in high assist, 45-74 PPS results in a medium level of assist, and greater than 75 PPS gives the least amount of assist. The PWM table can be populated with pulse width values (in msec). 

Judging from this article:
https://www.autozone.com/repairguides/Yaris-2007/Components-Systems/Vehicle-Speed-Sensor/_/P-0996b43f81b3d945

It looks like I should use a PWM+ output signal. 

Thanks for the reply and I appreciate all the help!

Andrew

Andrew

I am not sure about PWM signal, When I did my testing on the bench I was using a square wave generator and varing the frequency.
I also found an Analog sine wave would work it does not seem to be to critical.

Let us know how it works out

I will definitely keep you posted!

Andrew

Hello everyone,

This afternoon I finished the Prius EPS install on my Cougar.



If anyone wants to see the full install, it can be found here:

https://www.pro-touring.com/threads/109464-1967-Cougar-build-(over-700-pictures-and-videos)/page61

Starts at post 1203.

I also installed the wiring from the Holley Dominator to the Toyota ECU. I have not done any testing with it yet, because I need to do some reconfiguring of wires at the ECU, but I should have results soon. I had a buddy of mine make a spread sheet that does the math to convert Kevin's 3 inflection points to pulses per mile (ppm). In the Dominator output I can enter any PPM number which I am hoping will allow me to change the speed at which the middle level of assist is triggered. 

I welcome any thoughts and suggestions.

Andrew

Andrew, looks good.

Carrying the column tube all the way thru the firewall is a good idea, the amount of torque produced by the steering motor is equal to what you used to input via the steering wheel via the Armstrong Steering (manual). Without proper support it could rip the motor right off the dash bracket.

Question,  What ECU are you using that it is turning on without pulsing the VSS pin.  All my tests on the Yarus Non ABS ecu needed pulses to turn on, once on it would continue to provide power assist.  Varying the pulse rate would change the amount of assist provided.

The prius ECU (and I believe Yarus ABS) will turn on in failsafe without  pulse but to implement a working Speed sensitive steering they need a Can Buss connection that is much more than simply pulsing a single pin.

As far as wheel return goes, mine has not changed since the conversion but remember I have a 56 Fairlane and it has a very slow ratio in the steering box.

We have success!!!

I was originally using a Scion Xd ECU. It was functionally the same as the Prius ECU. It would turn on in "failsafe" mode as soon as pin 5 was energized. For me, the steering feel in "failsafe" mode was not that great. I have a really fast Total Control Products rack in the Cougar, and while steering effort without power assist was heavy, the feel and return to center were excellent. I also have a Yaris non-ABS ECU, same as you, and you are absolutely correct, it does not power up until there are some pulses on the VSS pin.

This afternoon it was drizzling (I have to work on my junk outside) but I managed to make some major improvements. I did what I had to do to move some pins around on my Dominator ECU. Then I took out the Scion ECU and installed the Yaris ECU. As already mentioned, it would not power up until I was moving. It took me a while to get my Holley 7" digital dash sorted out and reading the speed properly. In order for the Dominator ECU to output a speedometer signal you have to load a configuration file for the GM 4L60E transmission. Once that is done, on one of the configuration screens, you can specify tire size and rear gear ratio, and also the number of pulses per mile to output for the speedometer. I couldn't input my true rear gear (I am running 4.33 gears and 27" tires) because the 4L60 has a 40 tooth reluctor wheel for the VSS, while the T56 (which is what I am using) has a 17 tooth reluctor wheel. So I had to trick the math and inputting a gear ratio of 1.82 resulted in a more or less accurate speedometer. I verified this by comparing RPM and MPH in 4th (direct drive) at 45 and 60 mph. 

Then I used my buddies spreadsheet and inputted the right pulses per mile output based on the data that you generated with your square wave signal generator. His spreadsheet back calculates your 45 pulses per second value to MPH and pulses per mile. I wanted the middle level of assist to come on at 35mph, so that equates to 4629 pulses per mile (assuming he did the math right). 

I can say with certainty that the driving experience with the Yaris ECU is way better than the Scion ECU in "failsafe" mode. The "failsafe" mode must be it's own setting and maybe offers the middle level of assist and full damping, but this is purely a guess. With the VVS signal going to the ECU I got even more power assist at low speed, but it didn't feel as mushy. As speed increases, the steering tightens up and feels a lot more lively. I didn't have a chance to do any highway driving, but driving around town it was pretty darn good. 

I think the take-away for anyone that wants to implement this, you need to have a way of calibrating the VSS signal. I did this with the Holley Dominator ECU, but if you don't have EFI, you'll need box of some sort. Perhaps an option would be the Dakota Digital GPD box:

http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=837/category_id=287/mode=prod/prd837.htm

From the description it will read GPS speed and output a 4k ppm signal. Depending on your rear gear and tires, this might be close enough! Another option might be the DD speedo signal interface:
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/mode=prod/prd126.htm

With that box you would have to add a speed sensor to your transmission, but those are available with a pass through feature, meaning you can retain the cable speedometer drive. 

Andrew

Andrew

That's great, another milestone in the Electric Steering story.   I know it will work but yours is the first that I know of that is actually working.

If you get a chance after you have your pulse vs speed tables worked out would you post them, it would be a big help to me. I am still in the flashing LED mode but do have an inline VSS sender that I want to try, just need to fit myself under the dashboard.

Keep us posted