Vintage Mustang Forums banner

21 - 40 of 61 Posts

·
Registered
Joined
·
133 Posts
Alright. Awesome news. I wanted to temporarily try the PWM+ trigger to turn on the steering ECU. I am able to configure the output on the Dominator all in software. So I simply reprogrammed the original speedometer output and created the PWM+ output and assigned it to the same pin as the speedometer output (the speedometer output had to be virtually unpinned from that location). Anyway...

I set the frequency to 1000Hz and a duty cycle of 50%, so half the pulse is on and half the pulse is off, very much like a speedometer signal. Turned the ignition off, turned the ignition back on, and immediately had power assist. The diodes will be here tomorrow so I will add the second wire to the steering ECU speedometer input. The result should be having immediate PS as soon as the ignition is turned on and there after, it will receive the speedometer signal and operate by changing the level of assist based on speed.

Andrew
Good job; hopefully someone will device a cheaper speed control box without the dominator.
 

·
Registered
Joined
·
181 Posts
Discussion Starter #22
Good job; hopefully someone will device a cheaper speed control box without the dominator.
I am pretty sure that this box from Dakota Digital would work!

GPS Speed/ Compass Sender/ BIM

This would be a great option without having to install a VSS in the transmission.

Andrew
 

·
Registered
Joined
·
181 Posts
Discussion Starter #24
Some 80s Mustangs had this sender with both cable attachment and a speed sensor:

It's not just a matter of having a VSS. There are multiple solutions for that. There also needs to be box in the middle that serves as a signal conditioner and outputs the appropriate pulses per mile. I use the Holley Dominator for this because it is also my engine ECU.

If the above VSS is used, then Dakota Digital has another box that would work:

http://www.dakotadigital.com/pdf/SGI-5e.pdf

Andrew
 

·
Registered
Joined
·
133 Posts
I was thinking about using the above sensor that goes inline. Thanks for pointing out Dakota digital SGI-5E. The sensor and that box might be the ticket for people that do not use Dominator.
 

·
Registered
Joined
·
181 Posts
Discussion Starter #26
I was thinking about using the above sensor that goes inline. Thanks for pointing out Dakota digital SGI-5E. The sensor and that box might be the ticket for people that do not use Dominator.
It would be neat if there was a box out there that allowed you to specify the exact pulse per mile count, like I can with the Dominator. Maybe there is, I just have not seen it...:shrug:

I also really like the GPS box. If someone didn't want to mess with installing a VSS in the transmission, that is certainly a clean solution. Again, it would be nice to have the output be totally user defined.

Andrew
 

·
Registered
Joined
·
181 Posts
Discussion Starter #27
I have been digging deeper into the ins and outs of the Toyota EPAS system. One thing that I ran across is that the Toyota systems have a "torque sensor zero point calibration" that must be performed in case of a wheel re-alignment or if the motor assembly is replaced. This is described well here (toward the bottom of the page):

https://www.autoserviceprofessional.com/article/92544/Electronic-power-steering?Page=3

As far as I have seen, nobody has talked about this when installing the Toyota gear into older vehicles. This seems like a very important procedure and the fact that nobody is doing it, leads me to believe that it is partially (if not fully) to blame for the lack of centering that I (and others) are experiencing with the system.

Another thing that I found out, and this is a bit confusing, is that apparently, the Yaris ECU doesn't actually go into full speed assist mode unless it sees an RPM signal come across the CAN bus. This is confusing to me because I swear that my system does change the level of assist based on speed, but I have no concrete way to verify this, except for how it "feels" to drive. This has also been tested by others on the bench by connecting a square wave generator to the Yaris ECU speed input (pin 5) and reporting variability in assist level based on altering the pulsing frequency.

The information found here is invaluable (post #23):
Electric power steering - Page 2

I have been in email contact with the original poster (his name is Jared) of that thread. Here is a more complete pin-out for the Yaris steering ECU:



This is a wiring diagram that Jared put together.



Jared solved the CAN signal issue by using and custom programming the CANdo Auto Module:
CANdo AUTO - Automotive CAN Bus Module

Here is an excerpt from his post on the Toyota forum:

"I going to jump into technical which will make much more sense once you research the CAN system. I was able to find the hex decimal code for engine RPM is 2C4 wheel speed is either 0B0 or 0B2. Since my setup has a non ABS eps ecu has an analog wheel speed signal (input). I only needed the engine RPM on the CAN network so i will only go over how I programed the Cando for this. The Cando has 2 analog inputs that can be programed to then transmit programable CAN data. It also can have ten static data points programed and continually repeated. When you get the software open there are four tabs. "Input view", "Input setup", "CAN transmit" and "CAN setup" first off we need to go to "CAN setup" and change the setting to 500kps to match the network speed of the CAN system. Then back to the tab "CAN transmit". Now as I said earlier the hex for RPM is 2C4. The data length is 11 bit. The dlc is 8. The information I used was ramdomly picked after much trial and error. Almost 3 pages of codes I tried. I could set the RPM in connect my scan tool and see the RPM but still no assist. After much frustration I finally realised that it was a setting I had wrong. It was how often I had it repetting the message. The end result looked something like this 2C4 8 06 8A 00 19 00 00 92 09 Repeat rate 20 ms(milliseconds). All this done and turned the car on and immediate assist. I still have not been able to drive the car and see if it feels bettter. Still working on some idle issues with the engine. I could however tell the assist was greater. Last thing to work on is connecting the CAN wiring to the DLC so i can see about changing the setting for the assist level at idle."

What makes this more frustrating for me is that the Holley Dominator does use CAN communication. This is used for communication with Racepak and the Holley digital displays. The frustrating part is that the Holley CAN protocol is proprietary, so the odds of the Yaris steering computer "understanding" the Holley data packets are nil.

Before I go down the same path as Jared, I need to have a conversation with DCE. Their Microsteer ECU is speed sensitive. The only question remains is if the Microsteer ECU is compatible with the Toyota motor. If it is compatible, then I am inclined to ditch the Toyota ECU and simplify this ordeal by spending money on the Microsteer ECU instead of buying the CANdo box. I also need to find out how DCE handles the torque sensor center point calibration, as this seems rather important for obtaining satisfactory on-center feel and return.

I am open to thoughts and suggestions!!!

Andrew
 

·
Registered
Joined
·
1,122 Posts
I have been digging deeper into the ins and outs of the Toyota EPAS system. One thing that I ran across is that the Toyota systems have a "torque sensor zero point calibration" that must be performed in case of a wheel re-alignment or if the motor assembly is replaced. This is described well here (toward the bottom of the page):

https://www.autoserviceprofessional.com/article/92544/Electronic-power-steering?Page=3

As far as I have seen, nobody has talked about this when installing the Toyota gear into older vehicles. This seems like a very important procedure and the fact that nobody is doing it, leads me to believe that it is partially (if not fully) to blame for the lack of centering that I (and others) are experiencing with the system.
You have found some great information here, as well as in the rest of the post. As far as the zero point calibration, I believe it may not be applicable to our setup as everyone running the prius or yaris system is running in fail-safe mode. The calibration seems to be meant for a fully operational system where the complete steering system is live and receiving feedback from multiple sources (speed, rack, road condition, driver). I don't think it would be possible to fully integrate the Toyota system. The return to center issue I believe is largely caused by our vehicles inherent design with the addition of the electric assist - the best resolution so far is to increase caster.

In my particular case, I have never had a full RTC in both power and manual steering like I find in my newer cars (I have had both on the same car) - (Drive a ford focus and the electric steering literally snaps back to pointing straight no matter what speed or turning angle). The electric assist just makes it a bit more pronounced as the wheel requires less effort. My solution has been to increase caster to the point where the RTC is more prevalent. Maybe the RTC is also affected by tire size - I have always run no less than 235's on mine. Much larger than stock width.

As for now, I don't have an issue with the RTC on mine as I don't really notice it once I am driving. It becomes a characteristic of the car. Do I wish the RTC was like my Focus? Yes I do, but as long as I get 2/3's RTC, I am good. I typically drive through the turns and such so I am always holding and turning the wheel into the direction I want.

Keep up the great work, I am following this closely.
 

·
Registered
Joined
·
181 Posts
Discussion Starter #29
I always thought that the RTC issue was largely due to alignment, but I am proving myself wrong. My RTC before I installed the EPAS was excellent! I run 5 degrees of caster and nothing about the alignment has changed with the EPAS. I am also running tires that are much skinnier than stock, they are just little drag racing front runners from Mickey Thompson.

I wish I knew more about the stock Prius/Yaris system and exactly how it functions.

Andrew
 

·
Registered
Joined
·
1,150 Posts
When the power is disconnected from the EPS unit is there any drag? I would think that with a manual steering gear it just turns back into manual steering with little additional drag. It should drive the way it did before the ESP install. Fail-safe mode is so no average driver will lose control. But I'm sure you've tried it with no power.
 

·
Registered
Joined
·
181 Posts
Discussion Starter #32 (Edited)
When the power is disconnected from the EPS unit is there any drag? I would think that with a manual steering gear it just turns back into manual steering with little additional drag. It should drive the way it did before the ESP install. Fail-safe mode is so no average driver will lose control. But I'm sure you've tried it with no power.
I have done this, and driving with the power disconnected is the worst of both world. The steering effort is heavy and RTC is terrible. I want to be clear, the RTC with the old column was excellent...as in laser precise. Now, it is possible that when I installed the Prius gear and built the upper and lower tubes that something was off center. It is also possible that my input and output shafts are not 100% straight. However, when doing my build, I was keenly aware that keeping the tubes square and concentric to the motor and having the shafts be as straight as possible are super important. I wish I had a lathe, because the precision of the work would have been better. That said, I do not believe anything is off so much that it is causing a tremendous level of bind. Most steering maneuvers require less than 90 degrees of steering wheel movement at most (this would be the extreme when making a slow 90 degree turn).

Having said all that, I want to try to quantify what I am chasing here. Overall, I am very pleased with the results so far. The amount of RTC that I am talking about is the last 10-5 degrees of steering wheel rotation. I think if anyone drove my car, they would think it was perfectly adequate. I just want it to be as close to what it was before as possible, and if tuning up the electronics is a way to accomplish that, then I am willing to try.

The ultimate goals are:

1. Simulate an RPM signal over CAN so the steering ECU thinks the engine is running.
2. Properly terminate the CAN network so the steering ECU thinks there is normal communication with the engine ECM.
3. Make all the connections between the steering ECU and CAN to the DLC3 (OBDII) connector.
4. Attach a Toyota scanner and see if the steering ECU is throwing any codes (I am sure it is).
5. Clear codes (this is important because the torque sensor zero point calibration will not be performed when there are codes).
6. Perform torque sensor zero point calibration (hopefully this helps with return to center).
7. Varify that the steering ECU is seeing vehicle speed (this will show up on the scanner).
8. Enjoy EPAS to its fullest glory.

I also think having the ability to attach a scanner would be invaluable should there ever be an issue down the line. While these are junk yard parts, I really don't want to be randomly throwing parts at it if something stops working.

Andrew
 

·
Registered
Joined
·
3,865 Posts
I believe the RTC issue on EPAS is an artifact of the worm gear design of the assist motor. Worm gears have been used since the Bronze age on ships to completely eliminate the force of the sea (RTC) on the wheel and make long distance manual pilotage much more comfortable. Its frankly one of the major benefits of the design excepting in a car steering. There were companies that tried to do an electrically assisted RTC but could never get it to feel quite correct. I think your chasing your tail trying to fix an inherent flaw in the design if RTC is important to you. If I had my druthers, I'd have RTC but I won't ditch my EPAS because its almost nil. I have learned to drive it even competitively, its just a different car much more nuanced in its telepathy of what's going on but the data is still there.

I do not however think I would like it nearly as much without the rheostadt that comes with the Bruno box on my Equinox system. There is no one setting I could be happy with. I would love the variable assist if that gets solved...

Good luck,

M
 

·
Registered
Joined
·
181 Posts
Discussion Starter #34
I believe the RTC issue on EPAS is an artifact of the worm gear design of the assist motor. Worm gears have been used since the Bronze age on ships to completely eliminate the force of the sea (RTC) on the wheel and make long distance manual pilotage much more comfortable. Its frankly one of the major benefits of the design excepting in a car steering. There were companies that tried to do an electrically assisted RTC but could never get it to feel quite correct. I think your chasing your tail trying to fix an inherent flaw in the design if RTC is important to you. If I had my druthers, I'd have RTC but I won't ditch my EPAS because its almost nil. I have learned to drive it even competitively, its just a different car much more nuanced in its telepathy of what's going on but the data is still there.

I do not however think I would like it nearly as much without the rheostadt that comes with the Bruno box on my Equinox system. There is no one setting I could be happy with. I would love the variable assist if that gets solved...

Good luck,

M
M,

You make good points. I've been driving the car regularly, and the EPS is way better, overall, than manual steering. That said, I am going to tinker with it until I am satisfied that everything possible was done to make it as good as it can be. Someone on another forum reposted what another EPS experimenter found, and that is if there is any bind in the upper shaft, it will hinder the RTC. I did the best that I could with making sure that the upper shaft was square, but it probably has some run-out. I also did my best to make sure that the upper tube is square to the motor, but it is probably a little off. These two things will be addressed at some point (soon) to make sure there is zero bind in the upper shaft and tube. So I am tackling both the mechanical parts of the system, and just as importantly, the electronics part. After all, it is electronic assisted steering...:grin2:

Andrew
 

·
Registered
Joined
·
181 Posts
Discussion Starter #35
I'll be hanging out a lot more now. I need to keep my eye on you.
You need to be hanging out in your garage and finishing your Camaro! :)

I hope that everyone had a great Thanksgiving Holiday. My wife and I traveled to Wisconsin to visit her family, and we made it out just in time to miss the snow.

I am learning way more than I wanted about CAN, Arduino, RasberryPies, and all manner of other electronic gizmos, than I really planned on with this electronic steering business. However, I feel like I have to make the system work as it was intended by Toyota in order to get the most out of it and to be able to diagnose it in the future should something fail.

This afternoon I popped into the local junk yard to track down an OBDII connector (or two). I quickly realized that although the connectors are universal in terms of the mating portion, various manufacturers use different connector bodies and terminals. After I realized this, I started looking for the same make of car. It just so happened that I had relatively easy access to a few Nissans and they graciously offered their connectors in the form of a OBDII bouquet.



I only need one connector, but I figured it was a good idea to have extra wires and terminals, just in case.

I also managed to secure reliable help with the CANBUS emulator (that's what I am calling it). It seems that my buddy Blake (DigitalSolo....more like DigitalJedy) has been making these little boxes for his own projects. I told him what the box needed to do and he said "no problem." He builds these himself and installs them in really robust enclosures that are suited for a car environment.



The heart of it is an Arduino Nano (whateverthef**kthatis), and some other electronic bits. The header side uses Molex connectors that I will source from Mouser and make the appropriate harness.



I am pretty excited to get this rolling further along. Stay tuned for more soon!

Andrew
 

·
Registered
Joined
·
150 Posts
Andrew, here's a dumb question - not that I have the electrical skill to even understand half of this thread (!), but if I have an FiTech EFI and electronic speedo, I should be able to achieve the variable assist you mentioned, correct? I'd have to hire it out, but would love a little more boost from my corolla EPS at low speed! Its not terrible, but parking does require a little effort. I still need to check for binding as well.

On another note in case it helps someone else, the "jittery" steering does seem to be improving with miles. I only have about 200 so far. Someone else mentioned earlier that the new ball joints on my S or T front system could loosen up with time and may improve things. Could be whats going on? I'm sure some of it is me adjusting to the new system as well.
 

·
Registered
Joined
·
181 Posts
Discussion Starter #37
Andrew, .... if I have an FiTech EFI and electronic speedo, I should be able to achieve the variable assist you mentioned, correct? ....
I wish I was closer, I would gladly take your money and help you sort this out. :grin2:

I was actually all set to head your way earlier in November. There was a gentleman, also in Plano, that needed to have his 61 Impala, LS swap completely wired. We were all set, and then he claimed poverty due to having to take a trip to London with his wife...oh well...

Anyway...the answer to your question is "maybe." How is the electronic speedometer driven? Is there a VSS in the trans? As far as I know, the FiTech would have nothing to do with any of this, because it does not have VVS input at all.

You would need the Yaris non-ABS ECU (you can find them on Car-Part.com--Used Auto Parts Market) and you would most likely need a Dakota Digital speedometer converter box. This will allow you to send 4000ppm to the Yaris ECU and to your speedometer (the speed will need to be recalibrated, but that function should be built into the speedo), because you can split the square wave signals. The Yaris ECU seems to like 4000PPM (factory settings call for 43Hz at 37mph).

I would urge anyone going down the same path as I am, to think about making the Yaris ECU fully CAN enabled, which will also allow trouble codes to be scanned in the future.

If this box that Blake is making for me works, I am sure he can be convinced to make more, for a not so crazy fee. But let me be the guinea pig here...:pirate:

Andrew
 

·
Registered
Joined
·
153 Posts
With regard to variable assist, yes, that shouldn't be a problem. The options would be to either get CAN data from an ECU (if the FItech for example outputs it) or to read a variable signal (VSS or other pulsed output) into the Arduino and control the CAN data output to the EPAS unit based on the data. Either one is not terrible, though getting a flexible circuit to read VSS/pulsed output from lots of different systems universally is somewhat complicated (this needs to be fairly universal to make in any kind of bulk, since I need to design/manufacture circuit boards).

Right now I have the GM/Koyo unit in my car that gets variable voltage to control assist and I plan to use CANbus data from my AEM Infinity and a FET to control voltage output to get variable assist to it (I have the little knob kit right now to adjust it).

I'm planning to final test Andrew's box tonight and I'll get it shipped out to him for testing/validation and we can go from there. If this works, I can make it a lot more compact (they make an enclosure about half the size of the one pictured above) by integrating things more. The boards in place right now were made for driving 12V relays based on CAN data, and I'm repurposing them for the steering control, so they're a little larger than they have to be, but I want to find out exactly what we need before I commission new circuit boards, since designing them is tedious. :p

Oh, and hi, I'm Blake, I'm a nerd. :D
 

·
Registered
Joined
·
181 Posts
Discussion Starter #39
With regard to variable assist, yes, that shouldn't be a problem. The options would be to either get CAN data from an ECU (if the FItech for example outputs it) or to read a variable signal (VSS or other pulsed output) into the Arduino and control the CAN data output to the EPAS unit based on the data. Either one is not terrible, though getting a flexible circuit to read VSS/pulsed output from lots of different systems universally is somewhat complicated (this needs to be fairly universal to make in any kind of bulk, since I need to design/manufacture circuit boards).

Right now I have the GM/Koyo unit in my car that gets variable voltage to control assist and I plan to use CANbus data from my AEM Infinity and a FET to control voltage output to get variable assist to it (I have the little knob kit right now to adjust it).

I'm planning to final test Andrew's box tonight and I'll get it shipped out to him for testing/validation and we can go from there. If this works, I can make it a lot more compact (they make an enclosure about half the size of the one pictured above) by integrating things more. The boards in place right now were made for driving 12V relays based on CAN data, and I'm repurposing them for the steering control, so they're a little larger than they have to be, but I want to find out exactly what we need before I commission new circuit boards, since designing them is tedious. :p

Oh, and hi, I'm Blake, I'm a nerd. :D
Blake,

Thanks for chiming in! I am pretty excited to get this working.

For guys that have the Prius ECU making the speed based assist would require the speed information be sent over the CAN bus to the steering ECU. Presumably, the Prius steering ECU is also looking for a RPM signal over CAN. On the Prius and the Yaris WITH ABS, the speed signal is generated at the wheels and is first processed by the ABS (Toyota calls it the anti-skid) ECU first, then sent over CAN to other ECUs on the chain that may need it, like the steering ECU and the instrument cluster (Toyota calls it the combination meter).

If Blake can make a magic box that take a Hall effect speed sensor input and sends it over CAN in a manner that the steering ECU will understand, then it should work. The RPM signal is only used to turn the system on, so it actually doesn't need to vary. The smaller these boxes are, the better!!!

Andrew
 

·
Registered
Joined
·
181 Posts
Discussion Starter #40
Today I received the CAN simulator from Blake and last Friday I got the necessary connectors to build the harness.



I got the two Molex connectors for the box itself along with an OBDII connector.

Blake also emailed the pin-out diagram.

I am still sorting out exactly how I am going to do the wiring, but I am hoping to wire things up temporarily tomorrow and see what sort of trouble I get myself into.

If the power steering comes on when the CAN simulator is turned on, then I know it is working.

The other part of this will involve hooking up an OBDII scanner and seeing what codes are being sent by the steering ECU. I am hoping that I can do that with my BlueDriver Bluetooth dongle and my cell phone. Hopefully it will also let me reset the codes.

Wish me luck!

Andrew
 
21 - 40 of 61 Posts
Top