So here's the back story. During the process of putting my CA18DET into my S14, I decided to go with a Liquid to Air intercooler to shorten the piping up as much as possible. Since this is a fun car, and doesn't get used for any type of serious racing and is mostly driven on the street, this was the best route IMHO. Unfortunately, I also decided to put an HKS T4 turbo kit on it as well. The issue was that this requires a big intercooler (turbo should support close to 400hp). To fit it where I wanted, I had to ditch the stock crank pulley. I thought I could hack no A/C, no P/S, and no power brakes (that's a whole 'nother story), but I'm sick of it. The car's not fun to drive, and that's the whole point of it. So first off was to fix the P/S situation. What I came up with was to use a Power Steering pump from a Toyota MR2. If you don't know, they don't have have a traditional engine driven pump. It's driven by an electric motor mounted in the front of the car, close to the rack. Perfect. So I did some research, and discovered there are 2 different pumps. The 2nd gen, and the 3rd gen. If you're going to do this, you want the 3rd gen. The reason is that the pump, reservoir, motor, driver, and ECU are all integrated into the pump. I originally bought a 2nd gen and it was a mess from a wiring standpoint and I gave up on it.

So enough of my babbling, on to some pics.

These are various angles of the pump assembly itself.





Ok, so as you may have noticed, there are no pigtails coming out. Luckily, Toyota has part numbers for all of their plugs and wires with terminals that go with them. Here is a pic of what you'll need from Toyota;

What you need is 3 plugs, and 5 wires;
90980-12068 = Large 2 wire plug (goes on "left" side)
90980-10897 = Large 8 wire plug (goes in "middle")
90980-10942 = Smaller 4 wire plug (goes on "right" side)
82998-12500 = Wire pigtail with terminal for Large 2 wire plug (YOU NEED TWO OF THESE!)
82998-12440 = Wire pigtail with terminal for 2 smaller plugs (YOU NEED 3 OF THESE!)

Now for the wiring. I was lucky enough to have found a write up for using this pump for people who where wanting to convert their cars to battery powered electric vehicles. Unfortunately for us, this is a REALLY popular pump for them, and it's driven the price of the pumps up. But compared to the other options out there, it makes sense. This is really the BEST option for any type of Electro-Hydraulic conversion. So here is the wiring diagram;

You have to study this a bit to understand it if you're only used to looking at Nissan diagrams, but basically, the square in the middle is the ECU. Then all of the wiring associated with the pump is shown. The wires we're concerned with are as follows;
Pin 1 on Plug A (P6) 12v+ from common side of contactor/relay. USE LARGE GAUGE WIRE, THIS CAN PULL AS MUCH AS 50A!
Pin 2 on Plug A (P6) negative/ground USE LARGE GAUGE WIRE, THIS CAN PULL AS MUCH AS 50A!

Pin 5 on Plug B (P7) provides ground path for coil on relay
Pin 2 on Plug B (P7) INPUT into ECU from VSS (vehicle speed sensor). IIRC the S13 and S14 signals are the same type, so it should be fine. I will tell you that you need to get the signal that "leaves" the speedometer and goes towards the ECU on you're car. 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.

Pin 1 on Plug C (P8) 12v+ with the ignition switch in the "ON" or "RUN" position. This is the power for the electronics in the ECU.

If you're curious about the other wires that aren't used/needed.
IDUP = output from the PS ECU to the ECM to tell the ECM to increase the idle to compensate for the electrical load the pump is about to place on the system. This is basically the same function as a power steering pressure switch. When the switch closes, the computer knows that you're turning the steering wheel and the pump is working hard, so it increases the idle so that the engine revs don't drop. If you want to utilize this feature you'll have to have a stock ECU or a standalone, that can utilize this feature. Then you need to get another PN-82998-12440 (small wiring pigtail). I haven't checked the wiring differences so I'm not sure how to wire this up. I have a standalone, but it doesn't accommodate an idle load input, so I never researched how to use this, and all of the other documentation I've seen has been for electric cars, so they don't need it either. If someone is really interested in making this output work, I can get some more info and what it would take.

EFI = Input from the ECM. This wire is normally high (open). When the ECM is powered up, it brings this wire low (closed). This tells the PS ECU that the engine isn't running yet, and to not activate the pump. I may use this feature if I don't like the pump running before I start cranking the motor when I start it. But I have a standalone and have an output that can run this. If you're on any type of stock ECU, then you either have to live with the pump coming on when the ignition is in the "RUN" position, or you'd have to wire up a switch on the dash. I haven't looked into how it works yet because I'm not going to hook it up unless it's an issue.

SIL, TC, TS = These are all communication wires that end up at a data-link connector to retrieve internal codes, diagnose issues, etc. It's like an OBD port, just for the PS ECU. Not planning on buying the tool needed from Toyota to use this, so I didn't bother getting any info to wire it up.

WL = Warning Lamp. On the stock 3rd Gen MR2, there was a light on the dash that would illuminate if there was an issue with the power steering to warn the driver that a loss of power steering may occur. Once again, not planning on using this, so I didn't get any more info on it.

Some other notes. USE A 50 AMP FUSE AND RELAY ON THIS CIRCUIT!!! This pump pulls as much as 45 Amps under full load. The way this pump functions is interesting. It has an internal load sensor/circuitry. If you start the car, the pump will come on and ramp up in speed. If no load is detected, and no vehicle speed is detected, the pump will "idle down" to a much lower speed and current draw. As soon as you turn the wheel, the computer sees the drop in line pressure, and quickly ramps the pump speed back up to maintain pressure. (this is also the time that it would output the request for an increase in idle speed). This is nice in that you don't have a pump, constantly making pressure, and using HP from the motor all the time. You only draw power from the engine when needed. Then there is the input from the VSS. If this is connected (you don't HAVE to connect this BTW), the maximum speed the pump will run at is ramped down as vehicle speed increases.

That's where I'm at now. I still need to make a bracket to mount the pump, make a high pressure line to go from the pump to the rack, and run lines for a power steering cooler. I will tell you that the ECU is dependent on the power steering to cool the drivers for the pump. For normal driving, the stock "loop" will probably cool enough. But if you're doing any kind of racing, I would HIGHLY suggest a cooler. AFAIK, the driver isn't replaceable, and if it overheats and burns up, you have to buy the whole pump.

Wow, I've thought about doing this setup since our junkyard usually has a few 2nd gen MR2s but it seems like a huge pain.
Good luck!

Don't people also do some sort of mod to these so they can adjust the amount of steering assist?

If you use the 2nd Gen pump, there is an internal pressure regulator. What some people have done is wire the pump up so it runs all the time, and then adjusted the regulator down so that it gives a lower overall pressure.

As for these, you'd have to do something to fool the PS ECU into thinking you were going faster than you really were so it would give less assist. The issue with that is that I think there is a speed where the drop in assist stops. IE @ 80mph, it won't give any less assists, regardless of how much faster you go. (I made up the 80mph btw).

Ohh, I see.
Is setting up a 2nd gen pump like that a bit simpler than how you'd hook it up normally?
I've been wanting to have a bit less assist, and I don't think anyone makes a larger powersteering pulley for us (I don't even know if that'd work that well, probably need to mess with the valves or something), so I thought about doing a setup like this.

FYI, the pure electric PS systems are available on a TON of new cars.

In fact, we're in the middle of sourcing one for the 240Z (project article coming soon).

Razi wrote:Ohh, I see.
Is setting up a 2nd gen pump like that a bit simpler than how you'd hook it up normally?
I've been wanting to have a bit less assist, and I don't think anyone makes a larger powersteering pulley for us (I don't even know if that'd work that well, probably need to mess with the valves or something), so I thought about doing a setup like this.

The 2nd gen is VERY easy to hook up electrically if you don't want the speed control. Basically a relay, a fuse and some wiring. If you're interested, I've got my 2nd gen pump listed on eBay right now, but I'd be willing to give you a co-moderator discount, LOL!

AZhitman wrote:FYI, the pure electric PS systems are available on a TON of new cars.

In fact, we're in the middle of sourcing one for the 240Z (project article coming soon).

I contemplated pure electric, but I couldn't figure out how to fit the steering column from another car into mine, and still retain the collapsible safety feature AND clear all the pedals.

AZhitman wrote:FYI, the pure electric PS systems are available on a TON of new cars.

In fact, we're in the middle of sourcing one for the 240Z (project article coming soon).

Are those the ones with the electric assist directly on the column?
I saw a few at JCCS and thought that was a neat idea.

float_6969 wrote:

Razi wrote:Ohh, I see.
Is setting up a 2nd gen pump like that a bit simpler than how you'd hook it up normally?
I've been wanting to have a bit less assist, and I don't think anyone makes a larger powersteering pulley for us (I don't even know if that'd work that well, probably need to mess with the valves or something), so I thought about doing a setup like this.

The 2nd gen is VERY easy to hook up electrically if you don't want the speed control. Basically a relay, a fuse and some wiring. If you're interested, I've got my 2nd gen pump listed on eBay right now, but I'd be willing to give you a co-moderator discount, LOL!

Tempting! hahah
However, after looking at the FSM and searching the Internet, I've found some posts (some on Nico!) about adjusting the rack retainer's spring preload to stiffen the rack up.
I might give that a go first before messing with my pump stuff.

Yea, the electric assist on the column was the way I REALLY wanted to go, but I didn't see a way to make it fit the S14 with out buying a few from the junkyard to test with and ripping the dash out. I'm sure it could be done, but I didn't want to be the guinea pig, LOL. As for increasing the preload, that will probably work just as well.

Make sure you upgrade your alternator.

The MR2s with those steering pumps run a 100 amp alternator instead of the standard 70 amp one.

My brother has that system on his car, it's funny when the relay sticks one out of 500 starts.

I have been wanting to do this for over a year now, as the engine that I have lined up to eventually replace my sr comes from a car that uses pure electric p/s, but I haven't had the spare cash to throw at the pump.


This thread along with your manual brake conversion thread deliver.

asoomal wrote:Make sure you upgrade your alternator.

The MR2s with those steering pumps run a 100 amp alternator instead of the standard 70 amp one.

My brother has that system on his car, it's funny when the relay sticks one out of 500 starts.

Thanks for bringing that up! I forgot to mention that in preparation for this I upgraded the alternator to a Quest 100A alternator. That should be plenty, but I've thought about wiring an audio style capacitor across the battery to help deal with electrical loads.

kouki munster wrote:I have been wanting to do this for over a year now, as the engine that I have lined up to eventually replace my sr comes from a car that uses pure electric p/s, but I haven't had the spare cash to throw at the pump.


This thread along with your manual brake conversion thread deliver.

Thanks! I hope to have this completed in the next week or two. I was going to work on it this weekend, but I think I have a leaking valve stem seal in the Mazdaspeed Protege that I want to fix since it's the DD.

Hey, I have a 2jz powered s13. Full track car for drifting. Did you finish this set up? I'm not running any speed sensors on my car but I guess I'd use the speed sensor from the transmission and wire it straight to the mr2 pump computer. I work at Toyota and thing is 550$ for the whole unit so I may have to resort to finding a 2nd gen one in the junkyard...

The speed sensor input is only used to slow the pump down at higher vehicle speeds, as typically as speed goes up the amount of assistance needed will decrease.

Yeah I realize that but I don't want full power at 80mph. I don't want to be prone to under steer by turning the wheel so fast. Heck no powersteering at high speeds would be awesome but with the amount of steering angle. Maybe a good amount of pressure for the power steering may be good at high speeds to correct when at crazy angle. I can do it pretty simple by just taking the pump, mounting it and giving it full power at all times. I mean there's not that big of a downside is there?

I don't think the pump is designed to run for such a long period of time.

I haven't finished it yet. Life has gotten in the way. I don't think the pump would last long running full blast all of the time.

Yeah but this is a track car only. Hits the track tops 10 minutes at a time for practicing sessions.

That will help, but the pump depends on the power steering fluid for cooling and isn't designed for continuous use. Sure it would work, but these pumps are not even remotely cheap and the first time you burn one up and have to replaced it, you'll wish you'd spent the extra hour or so wiring it up to work properly.

Well the 3rd gen I probably won't find in the junkyard but the 2nd gen I probably will. I'll just use the sensor from the transmission Run it straight to the pump. Ill look at wiring pinouts and see what needs to be done for the 2nd gen pump wiring wise

The 2nd gen pump SUCK to wire up. You need the pump, the amplifier and the controller. They all have a bunch of wiring you have to do do make it work. It's such a pain in the a** that I sold my setup and found the 3rd gen in the junkyard. Everything is self contained and easy to mount. The price wasn't that different either. Maybe $100 more.

If you're dead set on the 2nd gen, then don't bother with the speed sensitive wiring. Just run it full blast all the time. There is an adjustment on the pump itself that will let you control how much pressure it makes. Be aware that the pump pulls like 60amps when running full blast and under load though.

That's neat to retain the hydraulic function of the rack, but would anyone know if there are any (junkyard age) cars with servo power steering, that could be swapped into a 240? Something that would allow the rack to be packed with grease like you're running it totally manual, but with the servo mounted in the collumn?

That'd be really neat, you could get rid of a whole type of fluid from the car, along with pump issues, leak issues, contamination/replacement issues, etc. (and servo steering should perform better than a hydraulic system, I guess increased wear in different places would be the only downside I can think of)

mechanicalmoron wrote:That's neat to retain the hydraulic function of the rack, but would anyone know if there are any (junkyard age) cars with servo power steering, that could be swapped into a 240? Something that would allow the rack to be packed with grease like you're running it totally manual, but with the servo mounted in the collumn?

That'd be really neat, you could get rid of a whole type of fluid from the car, along with pump issues, leak issues, contamination/replacement issues, etc. (and servo steering should perform better than a hydraulic system, I guess increased wear in different places would be the only downside I can think of)

I would also be interested if this ^^^^ would be possible

You mean like this?
http://www.nicoclub.com/archives/datsun ... ering.html

I contemplated something like this, but I couldn't find room under the dash. Greg insists that the S30 has less under-dash space than the S-chassis, and that it could be made to work.

float_6969 wrote:You mean like this?
http://www.nicoclub.com/archives/datsun ... ering.html

Do want! I wonder if we can convince them to do that for the s13/14 or at least sell the motor/gearbox and the control box so we can figure the rest of it out on our on.

Any idea if running both the front and back (HICAS) halves of the car from a single EHPS would break anything ? Looks like the MR2 Spyder pump is rated to max out around 1200 psi or so (from hearsay, I haven't bothered tracking down a FSM for the Spyder), and looking at S13 (what I'd be doing this in) FSM in the Steering section... it says 1038-1123 for the front and 924-995 for the back (though relief pressure is 853 on the pump...). If anything, I'd probably see lower flow than normal, right, with it split across the front and back? Or would I blow up the HICAS actuator? Alternatively, I guess I could keep my non-HICAS CA mech pump for the front and use just the EHPS for the back or vice versa, but then I'm even more concerned about over pressurizing the actuator ...

Trying to use this for HICAS would suck. First off, I would be really surprised if it could flow enough fluid to keep the pressure up for two racks. Secondly, the speed sensitive steering for the rear rack wouldn't work. You'd have to use it for just the front rack and keep the stock pump for the rear rack.

Why would it affect the speed sensitive steering? Just connect the VSS signal to the pump? There doesn't appear to be anything magic in the pump itself, that's in the solenoid / valve / etc, I'd think? Though, I can see the EHPS not keeping up with two racks..

I may end up just modifying or making a custom bracket to line up the KA24DE hicas pump on the CA, and make do with only a 3-ribbed belt instead of 4...

Dee couldn't come up with a CA18 HICAS pump and bracket?

The speed sensitive steering wouldn't be affected, the rear steering would decrease with speed. If you didn't hook up the VSS, you'd have a constant rate of assist, but I still seriously doubt that the one pump could keep up with both racks. Plus I have a feeling there is a reason Nissan went to the trouble of building that 2 level pump. I would imagine under/over driving the rear rack would make the behavior of the car unpredictable.

Just speculation though.