Today was a miserable looking day. It was raining all morning and I wasn't able to get as much done as I wanted, but I made solid progress.
The gentleman that first documented the Toyota Prius installation had a couple of suggestions as to how to make the upper shaft. Here is what he did on his Falcon:
I didn't see anything wrong with how he did it, but there is one problem, I don't have a lathe. Even if I did, instead of turning down the Falcon shaft, I would have bored out the Toyota stub to .750" to accept the Falcon shaft. Anyway, doesn't matter, no lathe.
Keep in mind, the Toyota stub has internal splines on the left side of the shaft. I made my first cut where he suggested, and as he noted a stock .750" shaft doesn't fit. However, notice that the Toyota stub has a little bulge, so if a cut can be made a little further to the right of where he made his cut, the ID gets bigger. So I took my wizwheelofdeath and cut off about 1/8" off the Toyota stub.
I was getting close now. Making that second cut got me really close to .750", so from here on out, I snuck up on it with a file. I wanted the Cougar shaft to fit snugly into the Toyota stub.
I cut the Cougar shaft a little long, so I can trim it exactly to the right length later. Here you can see the Cougar shaft fitting snugly into the Toyota stub.
You can also see by the silver mark, how far the Cougar shaft slides into the Toyota stub. This is important, because the Cougar shaft bottoms out on a taper that is inside the Toyota stub.
By having a tight fit at the opening of the stub and then having the shaft bottom out into a snug taper, assures that the two shafts are concentric to each other. This is obviously important, because we want as straight of a shaft as possible.
The final length of the Toyota stub ended up being right at 5.100"
Now it was time to cut the Cougar shaft to length. Again, a lathe would be the perfect way to do it, but no lathe. I had purchased a few .750" ID collar at Tractor Supply (officially my new favorite store) and I used one of them as a guide for my whizwheelofdeath.
This worked very well and gave a pretty square cut. The other thing that I wanted to do was stake the two shafts together. My welding is OK, but this is pretty critical hardware. So I drilled a 1/4" hole through both the Toyota stub and the Cougar shaft.
I then took a 1/4" grade 8 bolt and provided a mechanical pin that holds both shafts together. Then I cut the bolt and welded it in.
Then I welded the Toyota stub to the Cougar shaft.
The lower shaft is pretty straight forward. I used a Burgeson adapter with the Toyota spline on one side and a .750" smooth bore on the other side. Here I did exactly the same thing. Drilled a hole through the adapter and the shaft, 1/4" grade 8 bolt, welded bolt, then welded shaft to adapter.
Here is the final upper shaft. It ended up being 13 5/16" overall length. Keep in mind there is some wiggle room here because the left side of the shaft is splined. I made it as long as possible to engage those splined fully. The collar is there to keep the steering shaft from pulling out the top and it bottoms against the upper portion of the column. I really don't see this being an issue, because the splines on the Toyota stub fit really, really tightly on the input shaft of the motor, but I wanted a positive stop there anyway.
With the shaft installed and the upper tube attached you can see that the shaft length is perfect. You can see the groove for a circlip just above the stock upper bearing.
This is the lower shaft installed on the output side of the Toyota motor.
I ground flats on the end of the lower shaft (this was harder than it seemed) to mate with the u-joints for the intermediate shaft.
And here it is, fully assembled and ready for a coat of paint tomorrow.
The weather is supposed to be sunny tomorrow, so I am going to throw this thing in the car ASAP, get it temporarily wired up, and see if it actually works.
This morning it was in the mid 30s, but I managed to get outside and get some work done. My wife was on her way home, so the clock was ticking!
The big news is that IT WORKS! I hooked up the temporary wiring, turned on the key and I was rewarded with one hand steering. Now for some details, mostly in words, but a few pictures.
If you've been following this build, you might remember that I had some electrical problems when moving to Alabama. The issue was ultimately traced to a really crapy inline fuse holder. At that time I fixed the problem by installing a Delphi power distribution center under the hood. These are fairly common parts in 90s GM vehicles, and all of the miscellaneous parts can still be sourced from Mouser, and other vendors. Here is what it looks like.
On the bottom you can see the 4 gauge wire attaching to the central bus bar and power is fed to the fuses on the right. The fuses on the left are "duds" are are meant strictly as spares. The top fuse is what feeds a big relay under my dash that powers the Holley dash and a few other components. When I installed these parts, I knew that I was eventually going to do the EPS swap, so I ran extra wires from under the hood to under the dash. Position number two on the right is what powers the EPS. I also "stole" one of the other wires and used it as a ground, which I attached to the front of the cylinder head.
That took care of the power feeds, but the Toyota ECU also requires a "turn on" 12+ signal wire. Here is the schematic for the necessary connections:
To make everything work seamlessly, I decided that I was going to integrate the "turn on" circuit through the Holley Dominator ECU. I created a 12+ output and programmed it to turn at temperature above -30 degrees. This assures that the output is triggered during any realistic conditions. In other words, as soon as the ECU boots up (this takes about 5 seconds) the EPS is on.
I also added a wire from the Dominator to the Toyota ECU for a speed signal. As of right now, this feature will not be enabled but I will post more on this later. For now, the EPS will operate in "failsafe mode" and give a constant level of assist.
Then it was time to make everything pretty. I know this sounds weird given the patina look of my Cougar, but I couldn't put the raw metal column back in the car. Scott Drake makes a rattle can paint to match the Ford 'parchment" color, which is what my Cougar is. I painted the upper portion of the column in that color and the lower portion was painted black. For now I left the motor assembly "natural" but I may end up painting all of it black as well.
The last bit of details is the wiring for the turn signals. On Mustangs these wires are external to the column and have a little snap in cover. On Cougars, the wires are internal to the column and exit under the dash. Since I now have a lot of things occupying the space inside the upper tube the wires have to be external of the column tube. To make the 10 wires more presentable, I loomed them in an expanding covering.
That's about it for today. Tomorrow the weather is supposed to stay nice, so I will assemble everything and take it down the road for the first time with power steering.
The short answer is that as of right now, it is a mixed bag.
I can now easily steer the car with one hand, where this was absolutely impossible before. Driving through a parking lot is absolutely effortless. Parking is a simple one handed maneuver, etc...
With the fixed level of assist, it is overly boosted at any sort of speed above 30mph. The return to center is pretty bad. Before the EPS the steering wheel would snap to center, almost violently. I literally used to hang on to the wheel so it wouldn't return to center too quickly. Now, I have to sort of steer it back to straight.
At highway speed the on center feel is just mush. Before, small movements of the steering wheel were met with quite a bit of resistance as the wheels wanted to go straight. Now, small movements of the steering wheel are met with almost zero resistance and it doesn't want to snap straight again. So I found myself constantly having to steer to keep the car moving straight. This is annoying.
I am hoping that once I implement the speed input from the Dominator that all the bad stuff improves.
I won't bore everyone with the details, but I have it working now so the level of assist varies based on speed. With the limited driving that I did today (it was raining very hard) it seems a lot better! Once I get more miles on it, I will post more driving impressions.
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.
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):
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.
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 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 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 (whateverthe****thatis), 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!
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.
Today I was able to do some testing. I didn't want to wire everything up permanently only to have to chase things down later. So today I simply wanted to see if Blake's box works. The definition of "works" is, will the steering ECU turn on when it sees an RPM signal over CAN. I wanted to do more, but I didn't have enough terminals for the little connector that plugs into the steering ECU. There is a Prius at a junk yard not to far from me. I plan to take a trip and see what I can rob off it.
I connected the CANHi and CANLo at the steering ECU (on the D31 connector) to the CANHi and CANLo on Blake's box, making sure to twist the wires. I installed the wires into the Molex connectors for power and ground, ran the ground under the dash and had the power wire ready to connect to a temporary power source.
I turned the ignition ON, and as expected, there was no power assist. As soon as I applied power to Blake's box, almost instant assist. Blake said that his box should come online in less than a second, and that's about right.
I then went for a drive, not really expecting any difference, but to my surprise, there was a difference. At low speed there is considerably more assist and as speed increases there is a noticeable drop in assist. So contrary to my previous proclamations, and counter to the results that some people have done with bench testing, I don't believe that the speed sensitive steering is active if there is no CAN signal. This makes sense, because in the Yaris FSM it clearly states that if there is a CAN communication error with the engine ECM, it defaults into "failsafe" mode (fixed assist at the middle level). The RTC was about the same, but I expect this to improve once I get the OBDII connector wired up, scan and clear any codes, and perform the torque sensor zero point calibration.
Just a tiny little update. The weather has been cold and rainy, so no work is being done, but I did receive some parts. I like doing a proper wiring job and that means not doing any butt connections with the wires if it can possibly be avoided. This means spending some time looking at catalogs and data sheets for the right terminals.
With the Yaris (and Prius) steering ECUs the wiring that needs to happen is on the D31 connector. This is where the +12v power pin is located, along with the speed signal, CANHi and CANLo, etc....I have a D31 connector that I clipped from the donor car so what I needed were the actual terminals to avoid butt splicing wires and to add pins as needed. I was also looking to find the connector itself, but had no luck, but the Toyota dealership has them for $6. However, the dealership does not have and can't even look up the terminals. As far as I could tell the connector is made by TE Connectivity and the stock terminals had Tyco stamped on it. A little time spent in the TE Connectivity catalog resulted in a reward.
I know this may seem like overkill for most people, but if I am going to all this trouble, I might as well take it 100% of the way.
Once I get a dry sunny day, I can wire up the rest of the wires for the OBD2 connector and see if I can read fault code using the Blue Driver OBD2 dongle and android app.
On the morning of December 28th, my wife and headed out early in the morning for a road trip to Orlando, to visit a friend for New Years. As you all know by now, the Cougar lives outside, and of course has the dual DBW throttle bodies outside of the hood. For the most part, this has not been a problem. Unfortunately, it rained all night before our trip.
The Cougar fired up without any issues in the morning and we packed it up for our trip. We got to about 10 miles from the house, when I noticed that I no longer had throttle input. When the Holley Dominator ECU detects a fault in the DBW system, it goes into "limp home" mode, which fixes the TPS at 22%. With dual throttle bodies, this makes my little 5.3L scream at over 4000RPM with the clutch released. Clearly we weren't going to make it 550 miles, like this.
I shut it down and fired it up again and it seemed normal. I decided to press ahead and try to fix it on the road. As we drove, it went into "limp home" mode again and just as luck would have it, we stumbled on a Walmart. I pulled into the parking lot (thankfully there was no rain) and went inside. I needed something to dry out the TB connectors and then something to prevent it from happening again while we were on the road. The items I bought were:
1. Can of "office duster" (compressed air)
2. Bag of balloons
3. Can of playdoh
I pulled the front connector and it really wasn't that wet...hmmm...then I pulled the back connector and it was drenched inside. I used the can of compressed air to blow the connectors as dry as possible. Then I used the balloons to seal up the outside of the connectors. For good measure, I used the playdoh to seal up the parting line between the TB body and the connectors. This is what it looked like when we arrived in Orlando:
The fix got us driving again and never failed the whole time. Most of the trip looked like this through the windshield:
It took longer than expected, and rolled in around 8:00pm to be greeted with bourbon and steak. Life is good.
One of the things that I have noticed since I have built the Cougar, is that the engine started to tilt a little toward the passenger side, especially in the last year. From the very start I noticed that under heavy load, the engine did torque over pretty hard. I didn't think this was odd, since I was using stock 4th gen Camaro engine mounts. You can see in my very first drag strip pass how the engine tilts over:
So given that the mounts were rubber and that I made my own mounts, I thought one of two things was happening.
1. The mounts that I built have bent slightly.
2. The rubber inserts in the stock mounts have taken a set.
Once I was at John's house, we put the car on the lift just to look things over. It's always good to do an inspection and make sure everything was OK. The last thing I expected to find was this....driver's side:
It appears that the two halves of the mounts are just stamped together and the lips that hold the two halves together have broken.
We called a bunch of local parts stores, but nobody had them in stock, and I had to be back on the road on New Years day. We proceeded to drill out the holes and bolt the two halves back together using 4 3/8" bolts on each side.
Unfortunately, the rubber inserts have deformed over time, so the engine was still tilting to the passenger side just a little, but it is much better than before.
Eventually I will either replace the mounts with stock ones, or get poly inserts (I really don't want to do that), or get the new Holley mounts that are reinforced and have poly inserts.
At least I know now that the mounts that I built are in good working order!
I am up over 700 subscribers on my YouTube channel! I really appreciate everyone's support, and please consider subscribing, if you have not done so already.
As you may recall from my previous posts, I had turned down a 1.5" ID steel collar to fit inside the bottom of the upper tube. This allowed for a method of attaching the upper tube to the Prius motor. While I think was was a decent solution, I couldn't help but think that having only one set screw holding the upper tube to the motor was inadequate.
John has a little lathe, so we turned down another steel collar, so it would slip inside the upper column tube.
This collar was positioned a few inches up from the bottom collar and was welded in place through holes that we drilled through the tube.
The last thing that we did was add two more holes to each collar, so that each collar now has a total of 3 set screws that are located 120 degrees apart.
I felt that doing all this would keep the upper tube more firmly attached and square to the Prius motor.
I don't know that doing all this made any tangible difference in the way that the system functions, but if anyone is doing this from scratch, I think this is a good way to go.
As always, questions and comments are welcome. I also want to thank those of you that have subscribed to my YouTube channel. I really appreciate it!!!
Not much to report in terms of progress or any other updates, however, I finally managed to track down the Yazaki part numbers for the big power connector for the steering ECU. The same connector is used on both the Prius and the Yaris steering ECUs (and probably others of the same vintage).
The connector housing body is 7283-3521-40
The terminals are either 7116-3097-02 or 7116-3098-02 (either will probably work).
The big challenge is sourcing the terminals in the US. The connector body can be purchased from Toyota under PN 90980-12653, however, Toyota does not sell the terminals.
I was actually able to source the connector housing bodies from Japan, but what I originally thought were the correct terminals, ended up being the wrong ones.
If anyone knows a source for Yazaki parts in the US, please let me know.
Yes, I know, at the end of the day, if you have a pigtail that came with the donor steering ECU, you can solder or use a quality butt splice, and be done with it. However, for those that want to do this in the most optimal manner, this information will be quite valuable.
So here is just another tidbit of information, just in case anyone else wants to go down this rabbit hole. I found a vendor in Japan that has the connector housing body, but again, these can probably (I have not tried ordering myself) be sourced from your local Toyota dealership. I did successfully order the connector housing from the Japanese vendor.
They also list the matching terminals. Yes, they fit the connector, but as you can see from the picture, they are not designed for 8-10 gauge (5-8mm2) wire. They are designed for 3mm2 (12 gauge) wire. https://item.rakuten.co.jp/auc-hi-1000/f375-yz-s/
I suspect that the terminal above is Yazaki PN 7116-3096-02 (too small).
I have tried asking the vendor if the correct terminal is available, but as of yet, they have been unresponsive. The language barrier and the time difference is making communication problematic.