# Power Steering using Toyota MR2 EHPS pump



## rbgrn (Jul 24, 2007)

Very nice, dimitri!


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## slimdigits (Sep 5, 2008)

Very nice indeed!

How does this work out of you? How much power do you think it actually draws?


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## ice (Sep 8, 2008)

Whooah! that was awesome man!!!


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## RKM (Jun 9, 2008)

Thank you gentlmen.

Very helpful information!


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## TelnetManta (Jun 5, 2008)

Dimitri,

While hooking up my pump I found a small yet important mistake in your diagram. The ground that feeds the relay from pin five on the middle plug (pump) is actually the bottom left pin instead of the bottom right. The pin that you indicate is actually pin 8.

Thanks for the great work!!




Ben in SC


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## dimitri (May 16, 2008)

Ben,

look at original pinout from Toyota on the other picture, pin 5 is under pin 1, and pin 8 is diagonal from 1. My wiring diagram is a mirror image because I am showing harness on the pump, not the connector, but still 5 is under 1.

And I don't think my pump would be working if I had it wrong...


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## TelnetManta (Jun 5, 2008)

You're right about the pin numbers. My mistake. But, I have ground on pin 8, 5 doesnt give me any connectivity to ground. I dunno but thats how mines working and thought I would point it out for other.

Still just awesome work, Dimitri.


Ben


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## dimitri (May 16, 2008)

Ben,

you missed the point of this connection, its not supposed to be ground, its a control line from controller to relay. If it was ground then relay would be always on, then you don't even need the relay, just apply power constantly.

Using this line controller has ability to shut off power to the motor completely by raising this line, for whatever reason ( protection, overheat, speed signal, etc. ). Under normal condition and during the start this line is low, which allows relay to trip. If you are checking continuity by ohmmeter, do not expect this line to be ground, its not supposed to be.

Just try and connect everything as it states on diagram, I promise that relay will trip and pump will spin.


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## TelnetManta (Jun 5, 2008)

Okay, I guess I really need some help. Hope your around this morning.

I hooked everything up per your drawing (assuming I understand the relay symbols) and I cant get it to work.

Heres a breakdown:

Relay pin 85 to 12V
Relay Pin 86 to pump pin 5
Relay Pin 87 to 12V
Relay Pin 30 to pump Pin1 (next to gnd)

Pump pin 5 to switched 12V
Pump pin 2 to ground



Am I anywhere close? It seems that I never get the relay to close with the relay switch side ground connected to pin 5. I'm hoping that I have something wrong. As I mentioned earlier, and I understand what I was doing wrong, I can get the relay to close by connecting to pin 8 as it is directly tied to ground.


Thanks!!!
Ben


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## dimitri (May 16, 2008)

Are all connections solid when you apply power? For example I wanted to measure relay current and I applied controller power first, then hooked ammeter to relay afterwards. This failed because controller didn't sense relay circuit and didn't close it. Make sure whole schema is connected prior to applying power.

Otherwise I don't know what to say, I didn't come up with this schematics, it came from Toyota, you can clearly see it on attached diagram.


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## TelnetManta (Jun 5, 2008)

dimitri said:


> Are all connections solid when you apply power? For example I wanted to measure relay current and I applied controller power first, then hooked ammeter to relay afterwards. This failed because controller didn't sense relay circuit and didn't close it. Make sure whole schema is connected prior to applying power.
> 
> Otherwise I don't know what to say, I didn't come up with this schematics, it came from Toyota, you can clearly see it on attached diagram.



I went out and confirmed that I have 12V to the relay before connecting the switched 12v to pin1. I guess I'll just have to wire it directly and bypass the controller.. At least it does work that way.

Thanks for trying to help me.


Ben


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## jmauld (Sep 8, 2008)

Do you know what adapter is needed for the high-pressure line?


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## engineer_Bill (Jun 24, 2008)

I've got mine working, but what about the steering sensors, and speed sensors? when I put 12volts on the IGN wire it starts then stops for a few seconds then starts back up again. I would like the pump to run on demand.


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## dimitri (May 16, 2008)

I don't think original Toyota design uses steering sensors, there is no need for it if you use speed signal, which is marked VSS on the schematics. If you get VSS from your car connected to the pump, then it should stop running after your car reaches certain speed where PS is not needed. All this is theory for me because my car doesn't have compatible VSS signal, so my pump is running at all times.

Also, consider the power it takes to run idle is less than 100 Watts, which is miniscule compared to what main motor uses, does it really matter if your pump never stops running? PS pump would use 0.1% of your total battery power, is it worth complicating things with a dashboard switch? In case of emergency road condition where you will need to steer quickly, will you have time or even remember to flip the switch? I don't think so. I have been running PS pump for 4 months now, I see no impact on batteries or range, pump is idling when you drive straight, so why bother switching it?

Hope this helps.


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## engineer_Bill (Jun 24, 2008)

Yes I do have that info. There are a lot of empty, (unused) inputs and outputs. I was hoping someone had more detailed information on the signals Toyota originally used.


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## Thaniel (May 25, 2008)

jmauld said:


> Do you know what adapter is needed for the high-pressure line?


This is what I'm using
Pegasus parts (www.pegasusautoracing.com) #3276-005 Male 16 x 1.5mm Metric Concave Seat to -6AN Male, Steel. Of course also a 16mm crush washer. I polished the edge of the pump provide a good seal. I've yet to turn the thing on so I can't say that it doesn't leak. Hopefully I'll know this weekend. If it works I'll add to the wiki.


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## EAGERWJ (Aug 26, 2009)

Dimitri,

Am converting a 1999 Toyota Tacoma. Installing late model MR-2 pump. Diagram shows Engine Control Module wired in. Is ECU necessary?

Your great work is very helpful. Thanks, loads!

Walt in Corvallis, Oregon


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## gdirwin (Apr 7, 2009)

The 2001-2005 MR2 PS pumps have a sensor which detects loss of hydraulic pressure, and goes into the ECU, and ultimately to a red light on the dash...

I am also converting a Toyota ('01 RAV4) so hopefully I can use the VSS signal (to de-sensitize the steering at high speeds) and also will hook up the P/S pressure sensor into the stock ECU.


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## EAGERWJ (Aug 26, 2009)

Thanks for the information on the role of the Engine Control Module (ECM) in warning of low power steering fluid pressure. There are two connections between the ECM and the Power Steering ECU, shown on the Toyota Spider MR-2 wiring diagram. One is labeled "EFI" and is on pin B6. The other is labeled "IDUP" and is on pin B1. Do you know which provides the low pressure warning and what is the function of the other? It would also be interesting to know the function labeled "WL" that is on pin C4.


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## EAGERWJ (Aug 26, 2009)

Hello GDIRWIN,

With the help of you, Dimitri, Cap Weir and others I have nearly completed reverse engineering of the MR-2 Electro-Hydraulic Power Steering Pump and can describe the pump's characteristics and give a complete, basic wiring diagram for EV conversions. I will publish the results in the appropriate place on DIY Electric Vehicles website when I finish and can figure out how to do this. To complete this article I would like to know what the signal from the transmission-mounted, vehicle speed sensor such is on my 1999 Toyota Tacoma with standard transmission and no Automatic Braking System (ABS). This is because I use it as an example in the article of vehicles that are not equipped with ABS. The VSS for the MR-2 is taken from its ABS. If yours does not have ABS and does have the transmission-mounted sensor, then maybe you have this information. In any event you might be interested in receiving my current draft because the published version may be delayed until I find this information and the curve, "Vehicle Speed vs Pump Speed". If so, send me an e-mail and I will respond with this draft. Included will be figures such as the MR-2 vehicle speed signal form. My address is [email protected].
EAGERWJ


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## EAGERWJ (Aug 26, 2009)

Hello engineer Bill,

With the help of many DIY Electric Vehicle contributors and others I have very nearly completed reverse engineering of the MR-2 Electro-Hydraulic Power Steering Pump and can describe the pump's characteristics and give a complete, basic wiring diagram for its inclusion in EV conversions. I will publish the results in the appropriate place on DIY Electric Vehicles website when I finish and can figure out how to do this. To complete this article I would like to know what the signal is from the transmission-mounted, vehicle speed sensor on my 1999 Toyota Tacoma with standard transmission and no Automatic Braking System (ABS). This is because I use it as an example in the article of vehicles that are not equipped with ABS. The VSS for the MR-2 is taken from its ABS. If yours does not have ABS and does have the transmission-mounted sensor, then maybe you have this information. In any event you might be interested in receiving my current draft because the published version may be delayed until I find this information and the curve, "Vehicle Speed vs Pump Speed". If so, send me an e-mail and I will respond with this draft. Included will be figures such as the MR-2 vehicle speed signal form. My address is [email protected].
EAGERWJ


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## EAGERWJ (Aug 26, 2009)

Hello dimitri,

With the help of you and other DIY contributors I have nearly completed the reverse engineering of the MR-2 Electro-Hydraulic Power Steering Pump and can describe the pump's characteristics and give a complete, basic wiring diagram for EV conversions can use most of its functions. I will publish the results in the appropriate place on DIY Electric Vehicles website when I finish and can figure out how to do this. To complete this article I would like to know what the signal is from the transmission-mounted, vehicle speed sensor on my 1999 Toyota Tacoma with standard transmission and no Automatic Braking System (ABS). This is because I use it as an example in the article of vehicles that are not equipped with ABS. As you know the VSS for the MR-2 is taken from its ABS. If yours does not have ABS and does have the transmission-mounted sensor, then maybe you have this information or similar information for your vehicle. If so, then it may be practicable to design and make a conditioning circuit that will convert such signals to the MR-2 form if it is not there already. In any event you might be interested in receiving my current draft because the published version may be delayed until I find this information and the curve, "Vehicle Speed vs Pump Speed". If so, send me an e-mail and I will respond with this draft. Included will be figures such as the MR-2 vehicle speed signal form. My address is [email protected].
EAGERWJ


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## EAGERWJ (Aug 26, 2009)

Hello TelnetManta,

With the help of DIY contributors I have nearly completed the reverse engineering of the MR-2 Electro-Hydraulic Power Steering Pump and can describe the pump's characteristics and give a complete, basic wiring diagram for EV conversions. I will publish the results in the appropriate place on DIY Electric Vehicles website when I finish and can figure out how to do this. To complete this article I would like to know what the signal from the transmission-mounted, vehicle speed sensor such is on my 1999 Toyota Tacoma with standard transmission and no Automatic Braking System (ABS). This is because I use it as an example in the article of vehicles that are not equipped with ABS. The VS for the MR-2 is taken from its ABS. If yours does not have ABS and does have the transmission-mounted sensor, then maybe you have this information. In any event you might be interested in receiving my current draft because the published version may be delayed until I find this information and the curve, "Vehicle Speed vs Pump Speed". If so, send me an e-mail and I will respond with this draft. Included will be figures such as the MR-2 vehicle speed signal form. My address is [email protected].
EAGERWJ


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## drywaller (May 10, 2010)

Dimitri, thank you for taking the time to post this very helpful information. 
I have a question. I have a similar pump out of a 2005 volvo v50. The pump has only 5 leads, pos/neg end 3 other leads for "signals" from the host vehicle. 
I have priced the MR2 pumps and have found that they are more expensive and harder to find. The volvo pumps are much cheaper and easier to find. 
Can you point me in the direction as to where I could find info as to how to wire my pump?
Ill post a picture of my pump as well.
Thank you for any help.
Marco.


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## Thaniel (May 25, 2008)

drywaller said:


> Dimitri, thank you for taking the time to post this very helpful information.
> I have a question. I have a similar pump out of a 2005 volvo v50. The pump has only 5 leads, pos/neg end 3 other leads for "signals" from the host vehicle.
> I have priced the MR2 pumps and have found that they are more expensive and harder to find. The volvo pumps are much cheaper and easier to find.
> Can you point me in the direction as to where I could find info as to how to wire my pump?
> ...


Hey that's great to hear of another pump option. Best place to find wiring information will be the Factory service manual for the car it came from. Might be able to find it posted on the net or check to see if there are forums for that make model car. Let us know what you find.

Thaniel


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## drywaller (May 10, 2010)

Thaniel said:


> Hey that's great to hear of another pump option. Best place to find wiring information will be the Factory service manual for the car it came from. Might be able to find it posted on the net or check to see if there are forums for that make model car. Let us know what you find.
> 
> Thaniel


Thaniel thank you. I am happy that I was able to contribute, abeit a small contribution. 
I have found in my search that there are many many makes that are using these handy units.
I will check the volvo forums for the schematics.


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## hb0517 (Jun 4, 2010)

Based on Dmitri's wiring, is anyone having trouble with the MR2 pump spinning backwards? While it does spin, we're getting suction on the high pressure side of the pump, and aeration in the fluid reservoir whenever we crack the high pressure output fitting. But when we reverse the battery leads to the pump to change motor direction, the positive lead appears to be going directly to ground and immediately blows fuses.

Any guidance would be greatly appreciated.
HANK


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## Mac VaBch (Feb 14, 2009)

"Here are the Toyota part#'s for the electrical Connectors: These part#'s get the Plastic part only, The metal pin wiring parts are sold separately. Maybe someone can add the part#'s for those.
Part#'s Large connector 90980-12068
Middle connector 90980-10897
Small end connector 90980-10942"


Has anyone found the part #s associated with these connectors listed in post one of this thread? The local Toyota dealer is having problems finding them.


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## ARti (Oct 27, 2008)

I've got the part numbers for the individual pins within the connector shields identified earlier. These are for the "splice" which has the connector and waterproof plug for an individual pin all put together on a six inch pigtail. So you just push this splice into the appropriate slot of the connector and then connect it to a longer wire back into your harness.

The power connector for the pump takes two 82998-12500 
The other two connectors use 82998-12440. 


I ordered them from toyotapartscenter.net
I ordered six of the smaller ones (12440) just in case I loused one up. It turns out that they're pretty simple, so I've got a couple extra. Both items were $5.24 each as of mid April. With the cost of the connector shields, the whole order wound up at $72 with shipping. It's a little pricey, but I feel a lot better about the arrangement than my previous attempt consisting of squeezed crimp connectors with lots of electrical tape.


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## 5440 (Oct 3, 2010)

An old thread, but I learned so much and thought I would post my experience with this pump.

I recently installed this pump in an an 82 Toyota 4x4, with a gas engine in order to see if I could improve my mileage. On a recent trip from Vancouver to Regina (1700km) I appeared to save 40L, so it looks promising, but more logging on future trips will be required. I manually turned the pump off on the highway and want to use the VSS to control it better.

I did some measurements today and thought I would share them.

The pump draws about 8-9A after a cold start and could pull up to 44A (RPM >2000)in a full turn with my steering box.

I hooked up the TTL port on my function generator and noted the following current draw vs Freq (Hz).

Freq (Hz) Current (Amp)
20 Hz 8.5A
36 Hz 7A
52 Hz 5.6A
63 Hz 5A
83 Hz 4A
110 Hz ~3A
>150 Hz 2.2 to 2.7A

It was neat to ramp the pump speed up and down with the Fn gen.

Also to note, when starting at around 8A and not turning the wheel the pump would wind down little on it's own from around 8A to 5.9A to around 3.5A within about a minute.

But I still want the pump off at highway speeds and noticed that pulling the EFI wire to ground, shuts the pump off with 12V supplied to the pump via the IGN wire. I actually did this using a 1k resistor to be safe, but I bet the MR2, ECU just uses a relay or MOSFET to do this.

I am making a custom Cruise controller for my truck and will interface the VSS and, pump warning and EFI wires to it. I will just use a relay to ground for the EFI wire when it senses around 90kph and turn the pump back on at around 80 kph. The cruise controller also acts as a remote starter module to help set the choke and a PID routine to assist if the RPM is unstable after a really cold start.

I don't want the pump to start if the remote starter is functioning or if I just turn the key on (engine off, recall I'm still driving with a carb) so my controller will not able the pump unless it detects the engine started and the brake is depress so the EFI wire on the pump will come in handy here.

Other notes:

My reservoir had a leak when I received it. I also had to re-position reservoir return line so I had to the remove it anyway. I ended up getting a new O ring from a local bearing supplier for $0.50 ea. They just matched one up, so I got some spares at that price.

I am using Mobile, 100% Synthetic ATF like I have been doing for years with zero issues with this pump.

I swapped out the cheap 30A relay I was initially using and am now using a 75A, 12V device from Tyco, Part# V23232-D0001-X001. ebay was a good source for these for me to Canada.


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## YlliB (Aug 27, 2011)

@ 5440

I just obtained a 2002 MR2 PS pump and am planning on putting it in the S10 I am converting. Could you post a wiring diagram that non-electricians like myself would understand? Thanks. 

Bill Yancey


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## donx03 (Nov 19, 2011)

*GM Hydroboost for brakes USING MR2 Power Steering EHPS pump*

Hello Group I am starting my conversion, and I was wondering since the Gen3 MR2 pump is the best for Power Steering, is it safe to run the brakes off it using a GM hyrdoboost kit?

I'd like to know that this is safe. Here is some information about Hydroboost, this you can find on a 2001 Silverado, most Disels use hydroboost, because the engine has little or no vacuum.

*Hydroboost braking systems have been around for a long time. They have been used on many GM truck models and have been used on race cars for years. How does a hydroboost system work? Before I answer that question let me explain how the conventional power brake systems work. Most power brake systems employ a vacuum booster to provide pedal assistance when braking. That large drum attached to your brake cylinder in your engine compartment uses vacuum produced by your engine to help push the plunger in the brake cylinder when you apply pressure on the pedal.​ A hydroboost system uses hydraulic pressure to assist in pushing the plunger in the brake cylinder when you step on the pedal. The hydroboost unit simply replaces the vacuum booster and fits between the firewall and the brake master cylinder. Most hydroboost systems piggy-back on the power steering system for the hydraulic pressure.​ What are the advantages to the hydroboost system? The most noticeable difference is in the braking response and reduced pedal effort. A typical vacuum system depends on your engine for the vacuum source. Once engines are modified, they often do not produce sufficient vacuum to provide the assist necessary and therefore, stopping your car requires more pedal effort on the part of the driver. The hydroboost system is much smaller and frees up space in the engine compartment for things like deeper valve pan covers, etc.​* http://corvettec3.ca/hydro.htm]


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## YlliB (Aug 27, 2011)

I have yet to get my MR2 pump to work correctly, but I wold like to see this work, if I can get it to work. Main question might be the pressure differences between the two systems.


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## donx03 (Nov 19, 2011)

From what I gather which isn't much... is that, the GM Hydroboost requires 800-1200 psi, and the MR2 power steering pump is at 2000 psi @ 40 amps. 

Can somebody verify this?

Now I am aware with the 3rd Gen P/S pump when you don't turn the steering wheel, the pump will not turn on... Will this be the same for the brakes? The hydroboost, has about 3 brakes before it will require a pump, but lets assume just one brake... 
[I think another thread should be started on this topic - I'm just a newbie]


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## Thaniel (May 25, 2008)

*Re: GM Hydroboost for brakes USING MR2 Power Steering EHPS pump*



donx03 said:


> Hello Group I am starting my conversion, and I was wondering since the Gen3 MR2 pump is the best for Power Steering, is it safe to run the brakes off it using a GM hyrdoboost kit?


How do you measure safe? For me I think that is a hard question to answer. Since a failure at the pump still doesn't keep the car from stopping so not sure I would consider it a saftey question? However...

Does it work? I can answer that. In my conversion I am using a hydroboost from a mustang and a later model MR2 pump. Works great. People that have driven the car have actually been disapointed as it drives like a regular car. (the expect a EV to drive differently or somethign) I have the MR2 pump plumbed also into the power steering and hydroboost. Steering and braking feel is not noticably different from my ICE car.

I'll add this. The pump does make noise and mine is running all the time the key is on. When I brake hard it loads the pump a noticable amount. I'm considering having a shut down circuit or something so it turns off when not moving or something. I just love dead scilence when sitting still. When moving I don't notice the sound due to road noise etc.

Thaniel.


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## Thaniel (May 25, 2008)

donx03 said:


> Now I am aware with the 3rd Gen P/S pump when you don't turn the steering wheel, the pump will not turn on...


That is from the circuitry in the MR2. If you don't have or wire in such sensors and circuitry well....


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## donx03 (Nov 19, 2011)

Your suggesting the vss signal from the car has to be hooked up to the gen 3 p/s pump. For my first build, I am going to abandon this idea of using the hydroboost, a vacuum pump should be sufficient.


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## float_6969 (Jan 25, 2012)

I'm not doing an electric car conversion, but I wanted to let the OP know that this is great info! I have Nissan with an ICE and a large turbo. I had to remove the power steering to fit the turbo and wanted my PS back. I stumbled upon this site during my research. I've looked into many other EHPS setups, and IMHO, the 3rd Gen Spyder is the best setup. The Volvo unit is a little easier to wire, but doesn't give you the speed sensitive steering like the Toyota does. 

To answer some questions, you don't need the ECU wired in for it to work. The 2 wires connected to the ECU serve 2 purposes. The IDUP line stands for "Idle Up". This is basically a signal sent to the ECU to tell it that the pump is going to pull a large electrical load on the system and to increase the idle to compensate. The EFI signal is sent from the ECU to tell the EHPS system that the motor is running and that the EHPS system can be activated. With your electric cars, this wouldn't really be needed unless you wanted to wire it up so that the EHPS was deactivated if you had the key in the ACC position so that your battery consumption would be a little lower. IIRC this wire is brought low to de-activate the EHPS, and then high to enable it. Because I have an ICE vehicle with a standalon EMS, I'll be using this wire so that the system doesn't run with the engine off. 

The last 3 wires, SIL, TC, TS, are all for OBD signal transmission and aren't needed. You also don't need to hook up WL (Warning Lamp), but it's not hard to do, and will flash a code if there is a failure in the system. 

I hope this helps, and thanks again for the info!


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## 1995gstmcv (Apr 11, 2011)

float_6969 said:


> I'm not doing an electric car conversion, but I wanted to let the OP know that this is great info! I have Nissan with an ICE and a large turbo. I had to remove the power steering to fit the turbo and wanted my PS back. I stumbled upon this site during my research. I've looked into many other EHPS setups, and IMHO, the 3rd Gen Spyder is the best setup. The Volvo unit is a little easier to wire, but doesn't give you the speed sensitive steering like the Toyota does.
> 
> To answer some questions, you don't need the ECU wired in for it to work. The 2 wires connected to the ECU serve 2 purposes. The IDUP line stands for "Idle Up". This is basically a signal sent to the ECU to tell it that the pump is going to pull a large electrical load on the system and to increase the idle to compensate. The EFI signal is sent from the ECU to tell the EHPS system that the motor is running and that the EHPS system can be activated. With your electric cars, this wouldn't really be needed unless you wanted to wire it up so that the EHPS was deactivated if you had the key in the ACC position so that your battery consumption would be a little lower. IIRC this wire is brought low to de-activate the EHPS, and then high to enable it. Because I have an ICE vehicle with a standalon EMS, I'll be using this wire so that the system doesn't run with the engine off.
> 
> ...


We are in the same boat.

I have a Turbo as well and trying to get as much clearance as I can.
I have running the old MR2 Steering pump (1991-1995), which is way more complicated then the spyder (2000-2005).
I have almost 7 months with the system and I am very satisfy, I hooked it up with the ECU, Driver and Steering Sensor, which it makes it kind of quite and will shots off when there is no signal from the Steering Sensor nor the Speed Sensor, It short OFF as well when hits 80mph.
The ECU went off a couple of months ago, But because I have it all hooked up with the warning light, I checked the codes and was very easy to find the problem.
I looked at this thread long time ago and I am thinking on upgrading my old pump.
Now that you jump in and give more Information about what all the rest of the wiring does, I might considering on doing the upgrade.
I really would like to get as more info about the spyder pump to be able to hook it up the way it came from factory.

However, I am a little confused on the wiring diagram.
On my old system it has only two wires for the Warning light, which in the spyder has four wires.

WL (4-C W) is current from the ECU, to the Warning Light. 
14-B W-B (Warning Light) is ground for the Warning Light.

Now how about the other 2 wires?.
I am lost at this spot.

7.5 Fuse from the Gauge (10-B W-B) Warning Light?. Is this from the ACC, Ignition Switch or Accessory?.
(12-A) color W-B?. All what I know I'ts ground, which that makes it easy to hook up with out knowing what is it for.

Do the Spyder Warning light has 4 outlets?, I thought it was just 2, ground and current, which is all what the Warning light needs to light up.

If the Spyder warning light has 4 wires, Then I need the Spyder Warning light as well to mount it on my cluster.

Any one who can shine my Day would be appreciated.

Thanks in advance.

Miguel.


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## hookdraggr (Jul 8, 2012)

hb0517 said:


> Based on Dmitri's wiring, is anyone having trouble with the MR2 pump spinning backwards? While it does spin, we're getting suction on the high pressure side of the pump, and aeration in the fluid reservoir whenever we crack the high pressure output fitting. But when we reverse the battery leads to the pump to change motor direction, the positive lead appears to be going directly to ground and immediately blows fuses.
> 
> Any guidance would be greatly appreciated.
> HANK



Does anyone have an answer to this problem? I have just recently bought a MR2 hyd pump (2001-2005 with integrated ECU) and am having the exact same problem. The pump will turn on and run fine, but it runs backward. This is the third pump I have tried( peugeot 307, subaru xt6 and MR2) and all three have had something wrong with them. The 307 runs at what seems about 20 rpm and puts out zero pressure, the xt6 I cannot even get to turn on (although I haven't really tried anything more than just hooking a pos and neg leads to the big terminals) and the MR2 runs backward. I really would like to figure out the MR2 because it came with a really nice mounting bracket that fit perfectly and I have the fittings for the hyd lines already. Thanks in advance.


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## TEV (Nov 25, 2011)

I got a 2002 MR2 pump for my electric car conversion and when I first attempted to test it I connected only positive and negative wires from a 12v battery to +12/50A and GND from the picture and all I got was a spark, of course my first thought " I got a bad pump", No it wasn't bad, I was bad for not understanding the diagram: if you pay attention there is another "+12V Ignition Switch" going to pin1 of the 4 pins plug . When I connected that pin to the +12V, TOGETHER WITH "+12/50A"the pump started pumping oil from inside, I only power it just for a second because the pump wasn't connected to anything

Hope this help.


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## hookdraggr (Jul 8, 2012)

Thanks for the reply. I can get the pump to run, that is not the problem. The problem is that it runs backward. It pumps air instead of fluid. I have hooked the 12vdc (50 amp) pos and neg to the fat pins like in the picture on page one of this thread. Neg being the farthest pin outboard. The middle connector(6 pin) I have +12vdc going to pin 5, lower right corner. And the end connector(4 pin) I have +12vdc going to the upper right corner, pin 1. If +12vdc is connected directly to these pins, the internal relay kicks on and the pump runs for about a 1/2 second, then stops then runs backward at what I assume is full power. If I try to wire it up exactly as depicted in the picture with an external relay, it will not run at all. The voltage after the main (50 amp) relay, pin 86/coil, drops to about 8 volts and this is not enough to get the internal relay(inside the pump connected at pin 5) to switch on. 
I opened up the case of the ECU on the pump and found that pin 1 on the outside 4 pin connector was extremely corroded. In fact it fell apart when I tried to clean it. So I soldered in a new pin. Continuity checks and the pump does the same thing after being wired up again. HB0517 said that he has had the exact same problem, but so far no response from a PM I sent him. Has anyone else had a similar problem with the 2001 Spyder MR2 pump? There is no other corrosion inside the pump that I could see.
So far this hyd system has been nothing but frustration for me.  Any help is greatly appreciated. Thanks.


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## amperimetro (Aug 25, 2012)

Hi DImitri

I hope you can help me

I already hooked like your picture, but the pin5 that out of unit to the relay , he doesn't work.
I already mesure the volts between pin 86 and 85 relay's and i have a voltage just 1,..V when i turn on the dash switch.

I already put de ground direct to the 85 pin relay and the motor work but is some time he stopped, and if i turn of the dash switch and than turn on he works again than stopped again.

I cant put the speed signal because the car that i assemble this doensn't have speed sinal digital.

Please if you could help me 

Regards


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## Brandon (Dec 6, 2012)

I am having the same issues as some others on here are having. The pump is running backwards. Any reason why? What needs done.


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## float_6969 (Jan 25, 2012)

I'm just speculating, but maybe the pump see's there is no load when it's being bench tested and some programming code tells it to spin backward to try and bleed air from the system. I would be willing to bet that if the warning light was hooked up, it would be flashing a code for a fault. 

Just an idea though.


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## Brandon (Dec 6, 2012)

That is an interesting thought.

I was also wondering how many people hooked theses up according to the diagram? As someone pointed out the relay wont ever close because it isn't hooked to ground. I metered out the connectors and put the relay on 8 if I remember right and then it worked fine.


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## TEV (Nov 25, 2011)

I connected my pump using this diagram and is working very good. 







The pump computer is commanding the relay so off course you can't find ground until the computer is switching that pin to the ground. It's not just an electric motor and a pump, it's a very smart system with sensors and a computer , bench test may be tricky. If you want a dumb pump get the old style MR2 pump year 99 or earlier I think. Like this one:

http://www.ebay.com/itm/TOYOTA-MR2-...Parts_Accessories&hash=item484d3082d8&vxp=mtr


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## Brandon (Dec 6, 2012)

I wish I just had a "dumb" pump but already have two of these. The only thing I want them to do is turn on off the ign and run wide open until they are turned off. 

So what is going on? When I wired it up as shown nothing. When take power straight to the main power (number one on the left set of pins) and to number one on the right set of pins and gnd hooked up it runs. But it runs backwards. 

Not sure what is going on now. As soon as I take power and gnd to the main pins on the left it turns on but still backwards.

So something internal changes and pin 5 becomes a gnd? The pulse speed is optional correct?

Thanks for the reply's.


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## float_6969 (Jan 25, 2012)

I actually have a "dumb" MR2 pump I'm wanting to get rid of. Interested in a trade? I know it works, as I had it hooked up, but I didn't like that it ran full blast all the time as I didn't want to have to switch it.


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## Brandon (Dec 6, 2012)

I will keep you in mind. I shouldn't have said I have two. They are a friends of mine. I am the one who is to get them working. I only tried the one so far, dont know the scoop on the other.


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## float_6969 (Jan 25, 2012)

No worries, I just bought a 3rd gen pump on eBay today, but I'd like to recoupe some of my money from the pump I have now, or trade for a spare.


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## acemas99 (Jan 21, 2013)

Hey Everybody,

I'm new to the forum, and I appreciate all of the collective knowledge here on this EHPS pump.

I have a 3rd gen MR2 pump that I have wired up as indicated in Dmitri's original post. The external relay clicks back and forth when the ignition power is supplied, but the pump motor does not turn.

However, the pump will operate as intended when I connect the 8 gauge power directly to a 12 volt source (by passing the relay). When wired this way, the pump is on when the ignition power is supplied to the other pins, and off when the ignition power is not supplied.

I've tried several relays with the same result. Any ideas?

Thanks.


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## Carma (May 7, 2013)

hookdraggr said:


> Does anyone have an answer to this problem? I have just recently bought a MR2 hyd pump (2001-2005 with integrated ECU) and am having the exact same problem. The pump will turn on and run fine, but it runs backward. This is the third pump I have tried( peugeot 307, subaru xt6 and MR2) and all three have had something wrong with them. The 307 runs at what seems about 20 rpm and puts out zero pressure, the xt6 I cannot even get to turn on (although I haven't really tried anything more than just hooking a pos and neg leads to the big terminals) and the MR2 runs backward. I really would like to figure out the MR2 because it came with a really nice mounting bracket that fit perfectly and I have the fittings for the hyd lines already. Thanks in advance.


i have that's problem too.
there was a solution?

ps. i read errors from ecu
21,52,55
it's don't erase
When ig turn on ps pump runs but wrong direction. Then it's overheating i think and turn of.


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## pcihector (Aug 14, 2013)

donx03 said:


> Your suggesting the vss signal from the car has to be hooked up to the gen 3 p/s pump. For my first build, I am going to abandon this idea of using the hydroboost, a vacuum pump should be sufficient.


 Pre-93 Dodge Caravan with ABS does not have a vacuum booster. Has a hydrobooster, but it works with its own electric motor, and has a pressure reservoir. In that system you have 3 times of full brake pedal use before pump goes on to build pressure. If I remember correctly that system has a pressure switch with multiple functions (different presure-close circuits) that may allow for it to be wired to work as conventional brakes without the need of ABS controller.


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## saabwiz (Jun 21, 2014)

Has anybody tried using an electric pump from a Volvo s40? I think all I need is the +30 12volt and ground and then a +15 12 volt, I'm hoping it will run with out the can bus wires.


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## drywaller (May 10, 2010)

saabwiz said:


> Has anybody tried using an electric pump from a Volvo s40? I think all I need is the +30 12volt and ground and then a +15 12 volt, I'm hoping it will run with out the can bus wires.


All you need to make this pump run is a solid ground, 12 volt input and tie one of the three can wires to the 12 volt supply wire. Beware that there is a few second delay when powering the pump on. I posted a YouTube video showing how the pump works with a small danfoss steering valve.


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## drywaller (May 10, 2010)

Here's the YouTube link
https://www.youtube.com/watch?v=ygylYK-h0b8&feature=youtube_gdata_player


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## saabwiz (Jun 21, 2014)

Thanks drywaller appreciate the responce. Do you know off hand what size the fitting for the pressure side was?


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## drywaller (May 10, 2010)

I think it is a 1.5x14 bit don't hold me to that. I have one in my tool box. When I get a minute I'll grab it and see if I can confirm.


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## drywaller (May 10, 2010)

Could not confirm the size of the fitting. I'm almost certain the size I quoted. Here are a couple of pictures of my fitting.
I bought it from a hydraulic supply company in medford Oregon.


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## pyro6314 (Aug 12, 2014)

Hey, I have a 3rd gen MR2 Spyder pump wired up in my subaru. Everything seems to work right except there is a lag in the pump coming off idle to on a pressure drop from a quick steering input. As well it doesn't seem to respond to the VSS input.

I have been able to flash out ALL the codes, almost every one there is. Only problem is I cant clear them by toggling the Ts wire from ground. 

If anyone still watches this thread and has any insight please let me know. Thanks


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## Darbywk (Aug 24, 2014)

I have read many various website threads talking about MR2 EHPS in non-electric vehicles and they all seem to stress 75-80 amp relays and circuit breakers and 100 amp alternators. My question is if the 2001-2005 MR2 alternator was only 80 amps, why all the large amp relays/circuit breakers for a non-electric,(in my case a 1995 240SX with RB25DET, series II) when I have no large amp devices installed like large amp amplifiers and/or off-road lighting, etc.?

Also, I plan to use the RBs VSS signal to feed the 3rdgen MR2 EHPS. The RBs ECCS has the VSS on the tranny feeding the speedometer from ECCS terminal 53. Any advice on the correct wiring to EHPS middle plug would be very much appreciated.

Same for the RBs power steering oil pressure switch signal which is a 2 pin plug with pin one to ground and pin two to terminal 19 on the ECCS


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## xxslowpokexx (Sep 23, 2016)

Hey all,

I've been roaming around these parts for awhile as you have great information regarding steering and brake options. This is my second time registering (had issues logging in) And my first post. I am currently running an mr2 Spyder steering pump and almost went with a hydra boost setup however never really could find a good answer to how well it worked with this pump..So I went vacuum assist route.

My question if someone could help is that my MR2 spyder pump when wired according to the diagram wont run. My relay went bad and when I replaced it would no longer run and simply pulse blew. I ended up running an ignition switched power to the pump switch(its relayed) and a 50 amp self resetting buss to the motor directly from the battery to power it, and now it works. VSS was never hooked up. So my question is can someone post a photo of their relay wiring? I don't know if I missed something along the way but Id prefer to have the pump on a relay. I cant tell you HOW frustrated I was!! Many Thanks

Damon


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## Sute (Oct 22, 2016)

Hello,

Does anyone know what type of speed signal Toyota MR2 EHPS´s ECU understands? Regular square type signal coming from Hall sensors?

Thanks!


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## sholland (Jan 16, 2012)

Just hooked up the 2000-2005 MR2 pump and it appears to be running backwards? Does anyone know how to fix that? I've followed the diagram in the original post exactly.


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## brainshatterer (Jul 11, 2017)

Planning to find one of these for my 99 neon. I have a 2000 style neon pump in as it moves the resevoir to the top of pump to clean up engine bay, but the pump resevoir cap pukes fluid back out, as did my stock one on the back of the engine. Sick of the drips. but also of the squeals as I have an underdrive pulley. The 3rd gen is all self contained and not needing the actual ECU from the car correct? Is all that is needed is the whole unit and the plugs? And does anyone know offhand if the VSS from a 99 neon will work with it?
Thanks all.


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## Novablue454 (Mar 30, 2018)

Would someone double check my homework?

I am using OPs guide:








and this diagram









and came up with this:
Untitled by novablue454, on Flickr

So:
Relay 30 to Batt 12v
Relay 86 to switched 12v
Relay 87 to Pump Large Connector pin 1
Relay 85 to Pump Center Connector pin 5
Pump Large Connector pin 2 to Chassis Ground
Pump Small 4 wire connector pin 1 to same switched 12v as Relay 86


What has me confused, is that in every diagram I can find replay pin 85 goes to a chassis ground, but the diagram in the OP has it going to pin 5 of the center plug. Is pin 5 just a ground source? If so, what is the purpose of using it rather than a chassis ground point?

Also, what is the relay even doing in this system? Seems that just running a constant 12v source and ground to the 2 pin connector, and a switched 12v to the 4 wire connector pin 1 would achieve the same thing with a lot less wiring and headache? But I am also an electrical idiot, so I'd like to understand why I am doing what I am doing.

Thanks!


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## collector55 (May 14, 2019)

Hello, I read your post. Very interesting and informative. I want to put an Electric power steering pump in an older Mercedes. The car has a re-circulating ball type steering box. Not a rack. Also, there is no source for a speed pulse signal. Can it be done> Suggestions please? Regards.


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## willeywilson (Aug 12, 2020)

Did anyone ever get to the bottom of the pump running backwards? I have hooked up my pump exactly as the schematics and it runs, but has only swallowed a small amount of oil and appears to be running at full speed but not providing any assistance. The oil level appears to rise when the pump is running and therefore I believe it is running backwards.
Thanks in advance
Adam


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## willeywilson (Aug 12, 2020)

Just for anyone reading this and struggling like I was.

Take the motor cap off (where the stator magnets are glued), spin it 30° to the next fixings holes and try again. The arrangement of the magnets inside means if the motor cap is removed and fitted wrong the motor will spin backwards. 

You will need to test the other two positions to figure out which has most torque.


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