Electo-Hydraulic Power Steering (EHPS) conversion on S14

[72Pantera]

The reason is that the VSS outputs a sine wave. The speedometer converts this to a square wave, and outputs it to the ECU. You want this "conditioned" signal to input into the PS ECU.

I'm looking for some help with my MR2 EHPS pump. I'm pretty handy with most wiring but this has a special signal & I don't understand it. I put a 3rd gen MR2 pump in my 72 Pantera about a year ago. I would like to use my speedo signal to control the pumps pressure. The signal is coming from an "Auto Meter speedo sender" model #5291. It sends a square wave signal with 16 pulses per revolution. I don't know if it is the right kind of signal or not but it doesn't work. Any help would be appreciated.

[float_6969]

My guess would be that the pulse count is too high. I THINK the Toyota VSS is only 2 pulses per rotation. Don't quote me on that though. I don't have mine hooked up and running, so I can't give any more info than that.

[72Pantera]

I saw on a website that the pump is looking for 4000 pulses per mile. Mine is putting out 30,000 per mile, so I bought a signal transformer from Dakota Digital to change it to 4000 but that didn't work. I tried several different settings but nothing worked so far.

[72Pantera]

Do you know if the signals are compatible? My speedo sender puts out a square wave signal, (I don't understand what that is exactly). I don't know what type signal the Toyota pump is looking for.

[float_6969]

I THINK the Toyota is looking for a square wave (or modified sine wave) signal. So the signal type shouldn't be an issue. Some backround;

The output of ALL speed sensors (it doesn't matter the type) is of a sine wave. Digital electronics don't like sine waves. So there is usually some sort of conversion process somewhere. Sometimes it's internal to the sensor, so the sensor already outputs a square wave and the conversion is done internally. Some vehicles (like the 240sx and many other Nissans) output a sine wave signal from the speed sensor, which is fed to the speedometer. The speedometer converts that to a square wave and outputs it to the ECU and ABS controller. The Dakota Digital signal converter should allow you to convert the square wave signal to a sine wave or analog wave signal. I don't THINK that's the signal the EHPS controller is looking for, but it won't damage it either.

[float_6969]

I just rechecked my info. The pump definitely wants the square wave signal. 4000ppm sounds right as well. Are you sure you're inputting the signal into the right pin? You might also make sure the grounds between the signal converter and the EHPS controller are good and don't have much resistance between them.

[fakieSI]

was this project ever finished? or even installed? lol Been looking around at doing this and have came across the 2 best articles for doing it. One of which is this one and the other one was done on a honda but I am wondering how long the pump would last like stated in this thread. There are people in that thread saying the pump has lasted like 4+ years. Link to other article below.

http://honda-tech.com/road-racing-autoc ... 562/page1/

[float_6969]

I had to put it on hold to do an engine rebuild. The engine rebuild is nearly done and I plan on completing the EHPS conversion before I put the engine back in. All I got done was to build a bracket and mounted the pump in the engine bay.

I also saw that Honda thread. He had it set to run basically full blast all the time. There is a pressure adjustment on the pump, and he turned that down to suit him. From what I understand the brushes won't last as long as they should running at full RPM all the time. What does that mean in terms of time? I have no idea.

[fakieSI]

Ok cool thanks for the reply

[ZaK687]

Hey, sorry to bump an old thread butjust wanted to see if you got the pump running well after your rebuild?

[float_6969]

I still don't have the pump running. I have the lines run, I just need to do wiring, but winter caught up to me here and I haven't been able to work on it

[float_6969]

Small update, The pump is installed, hydraulic lines are run and the electrical is temporarily hooked up to check functions and it seems to work great! I still can't drive the car yet because I can't add coolant because I'm waiting on parts, but as soon as I can get the car driving, I'll get a review up on this. As of right now, I don't have the speed signal hooked up. Once I get it actually driving around I may try hooking it up just to see what it does. Initial impressions are good. Current draw isn't as much as I thought it would be, the highest I ever saw was 37A, though turning the wheel back and forth while it's just stationary may not fully load the pump up. Pump isn't terribly noisy, I don't think you could hear it at all if the engine was running. So far, I'm happy with it.

[float_6969]

OK, final update on this. The system works well. I have it wired up so that it doesn't come on until the engine is running. When you first power it up it pulls almost 50A, and that was slowing down the starter noticeably. In the depths of winter, I could see that draw being enough to effect the ability of the engine to start.

The boost from it is close to stock, falling on the side of being heavy. I doubt anyone would even notice that it wasn't stock just driving it. I also wired up the VSS output from the speedometer, just out of curiosity. I didn't really notice much of a difference, but it was definitely a little more heavy on the highway.

And now that I went to all that trouble to get it installed and working, I'm going to have to remove it and sell it. The only spot I had in my engine bay for it was on the drivers side, near the radiator. Tonight I just realized that the A/C compressor won't clear the pump where I have it mounted. I'm not giving up A/C on this build, as I've had enough A/C-less cars in the past.

Once I get it pulled out, I'll get a F/S ad posted and I'll link it in here.

[fakieSI]

Do you think if hard lines were constructed and ran. Could you run this from the trunk? The reason I suggest hard lines would be so there is minimal flex running such a long distance. I know I am bumping a very old thread but so far is the write up I am going with. The battery is already relocated in the truck and the alternator has been swapped out for the 120amp quest one. Just trying to free up some space in the bay and displace a little weight towards the rear.

[AZhitman]

Ryan - We need to talk. I can fix your issue and you won't need to give up AC.

[float_6969]

Do you think if hard lines were constructed and ran. Could you run this from the trunk? The reason I suggest hard lines would be so there is minimal flex running such a long distance. I know I am bumping a very old thread but so far is the write up I am going with. The battery is already relocated in the truck and the alternator has been swapped out for the 120amp quest one. Just trying to free up some space in the bay and displace a little weight towards the rear.

It's not an old thread, I JUST updated it a few days ago on my last post.

As for locating it in the trunk, yes, it could definitely be located in the trunk. I had considered doing that actually, but since this whole process started, a lot has changed and I'm able to run standard power steering now. That being said, I'd still prefer to run electric. Anything to simplify the engine bay and have fewer fluids to worry about is good news in my book. I also agree that running hard lines as much as possible is a good idea too.

Do you already have a pump? If not, this one will be for sale soon.

Ryan - We need to talk. I can fix your issue and you won't need to give up AC.

Giving up AC is not an option. Giving up the EHPS is what is going to happen now. My plan was to put regualr PS back on it, but I'd like to hear what you have up your sleeve. PM'ing you now...

[AZhitman]

Yeah. EHPS is unnecessary, considering some of the cool stuff we're doing lately.

[fakieSI]

Sorry for the extreme delay I have had alot going on lately and my poor project has been side lined lol. I really appreciate the feed back and input. I am going to run a newer style pump that is being used on the 2014-current Nissan Pathfinders. I work at the plant in Smynra and look at the these pumps daily. I have talked to a couple of the engineers and got the wiring pin out on the pump. These pumps can be had for 75$-100$ on ebay so I am really excited to get started on it.

[float_6969]

What chassis is this going in? I'm in the middle of having a fully electric power steering column made right now for my S14, but it should be easily adaptable to other chassis'.

[fakieSI]

Its a S14 Kouki

[fakieSI]

If you dont mind me asking what are you salvaging a full electric column from?

[float_6969]

Oh, I'm not getting a full electric column from another vehicle. The owner of this site, AZHitman, is also involved with a company called http://zpowersteering.com/. They make electric column conversions for old Z cars. He saw this thread and said to talk to him. Long story short, I sent a spare column down to have it modified to accept the kit that he uses on the Z cars. I'm still waiting to get it back. The guy that does the work was busy getting ready for SEMA and had to put it on the backburner until he gets back.

[fakieSI]

I have come across that before. I was looking into what it would cost to modernize one of those Zs for a buddy and came across them. If memory serves correct its rather expensive.

[fakieSI]

The new rouges are electric columns so I didn't know if you had managed to score one and was chopping it up to get it to work lol.

[float_6969]

I don't have a cost on anything yet, but in my particular situation, I realized there's something wrong with my rack, so I was looking at a rack, and a pump, plus the associated lines if I wanted to get the PS working again.

[AZhitman]

The new rouges are electric columns so I didn't know if you had managed to score one and was chopping it up to get it to work lol.

Won't work. That's drive-by-wire, which is totally different.

The machining and fabrication (not to mention the programming, the actual motor, and the wiring harness) to make electric-assist power steering work on an older car is pretty daunting.

The EPS samples torque differential 30 times per second, processes this information, and applies assist accordingly - all while maintaining a physical connection between the driver's hands on the wheel and the tire's contact patch on the road.

$1500 is a hell of a deal for all that technology and precision.

[float_6969]

It's hhhheeerrreee! Fully electric column is done and at my house. Now to get it installed. Watch for updates here; fully-electric-steering-column-for-s14-t612421.html