Well, thanks to John (weejc), I have a knackered EHPS pump: add to that some valuable time, and I was today able to dive into the mystery of the Roadster PS....! s:D :D s:D
I dismantled the unit this morning, and after a careful scrutineering session, a few things have bacome apparent:
1) It will be virtually impossible to test any future repairs to these pumps other than actually fitting them to your car, as the EHPS ECU "talks" to the main engine ECU, and the car "spd" signal controls the motor speed. It may be possible to connect P6-1 to 12v and P6-2 to ground to start the motor, though....?
2) It appears that the actual vane assembly is really quite clever: The individual vanes (10 of them) float in a slot. This allows them to slide in and out round an internal cam housing.
PS fluid is applied to the inside edge of each vane from a circular groove: the pressure of this fluid could determine the actual power applied to the steering rack (along with the motor speed?)
Centrifugal force makes the vanes outer edges follow the cam profile: this could be one possible problem area, as the vane-to-slot clearances are obviously critical and any dirt preventing easy sliding will reduce the pressure overall.
2 of the 10 vanes "sticking will sap 20% of the pressure generated....
3) When I removed the motor case, I found a large quantity of dust over everything: turns out it is the copper from the commutator, which has been worn away over the last decade....! This cannot be helping things, can it...!? s:D :D s:D
I reckon that the problem is here, and may be 2-fold:
If current is being arced away from the brushes, then the motor speed will drop, and the current flow will increase.
A code of C1523 will be thrown up if the current exceeds 100A for 0.1 seconds. (Interestingly, the EHPS fuse is rated @ 50A..!?)
Code C1521 is thrown if current exceeds 33A for 248 secs, OR 40A for 96 secs OR motor temp exceeds 200 degress C.
I dont think the problem is with any wear to the pump assembly itself: I found no distorted / worn gaskets, the vanes looked fine and slid as they should, and the motor brushes were only about 30% worn.......
I have a spare 1ZZ ECU, and I may buy a PS rack and actually make a test rig for the setup.....?
(BTW: pix to follow..! s:wink: :wink: s:wink: )
Here's the beast in question:
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/EHPSPumppn-1.jpg)
Inside the ECU: not worth opening, IMHO...but I needed to know what was in there...!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/InsideECU-1.jpg)
Reservoir removed:
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Resremoved-1.jpg)
Valve removed!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/FlowCVremoved.jpg)
The vane assembly:
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Vanereass.jpg)
A single vane: dead easy to lose, these...!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/avane-1.jpg)
Dirty motor insides...!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Dirtymotorguts-1.jpg)
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Dirtydeps-1.jpg)
Cleaned up!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Cleaned2-1.jpg)
Vane dis-assembled!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/disvaneassy.jpg)
The flow control valve is something I did not dissect: it is possible that something in there fails / spring loses tension over time, etc, which could be the root cause of problems.....?
But we need some more detailed info about any (future) failures to really nail this: codes, symptoms of failure, etc.......?
It could be that the cause of problems / failure could be simply down to an over-worn commutator? It certainly is the only thing that shows signs of wear and tear..?
I did not want to pull the motor shaft, as it did not want to comply, and I just got the feeling that I should not be more persistent...... s:wink: :wink: s:wink:
..Didn't want to "break" anything, as it was all going so well......! s:D :D s:D
Nice work.
I wouldn't be surprised if that clean up has done the job! Let us know how it works out.
Every failed Toyota screen wash pump I've come across (Yaris, MR2, Avensis) has been resurrected with a fiddley but simple enough stripdown, clean up, and reseal with hot glue gun glue (or araldite, whatevers to hand!), without even replacing any components/brushes.
Okay, completely different pump, but similar principle!
How it is wired up and how to wire it away from an MR2 is explained here: m http://k20a.org/forum/showthread.php?t=58599 (http://k20a.org/forum/showthread.php?t=58599) m which might help if setting it up on a bench.
Thats really useful info and pics matey. I've a couple of tired PS units here and was looking at the replacement vane options with MrT .... but it seems that my first port of call is now going to be in cleaning up the motor housing, commutator and brushes and seeing if that brings the kit back to life. Thanks. s8) 8) s8)
Keep us posted.
That's really interesting, from the quantity of dust in the motor, I would expect the brushes will be well worn - can you see how long they are? if they are really short, then the commutator may be scored where the connecting wires embedded in the brushes have become exposed. Most of the faults reported sound like intermittent brush contact and i would guess thats whats wrong with your motor. If you can get the brushes out, then you may be able to get new ones from m http://www.carbonbrush.co.uk (http://www.carbonbrush.co.uk) m . You should be able to get the motor working by connecting the RH pin (pin 1) of the 2 pin connector to +ve and the LH pin (pin 2) to -ve and the top RH pin (pin 1)of the 4 pin connector to +ve.
No, the brushes are fine: they are about 15mm long...!
There is an oval slot in the side of the metal brush guide, through which the brush wire is fed.
There is room for the brush to wear by another 8-10mm: I would suggest that these brushes have only worn by about 5mm...?
I reckon the copper dust could hold the key: it was coating everything! s:shock: :shock: s:shock:
The commutator is worn down by a fair amount, though......I wasn't able to accurately measure the wear, but it looked in the region of 2-3mm..!!
There doesn't seem to be any electrical feedback for PS system pressure (like the Aircon system has)? The motor speed seems to be purely controlled by vehicle speed ("SPD" signal). There is a feed from the ECM that shuts the PS down when engine load is high ("PSCT"): "IDUP" tells the ECM to increase idle speed slightly when the PS motor is running...
So it would be difficult for the ECM to throw a CEL if the system pressure dropped below a certain level, especially if it is also variable dependent on vehicle speed?
It has to be purely on motor temperature and current draw.......?
I can start the motor, but unless it is loaded (ie: fitted to a PS rack, filled with fluid and fed an SPD signal), I can actually test very little.. s:? :? s:?
I can generate a PWM no problem, but I need to simulate the hydraulic loading.......
...or just connect it to a rack?! s:wink: :wink: s:wink:
I'm sure I read somewhere that the fluid pressure is 700psi+...!!? s:shock: :shock: s:shock:
Wouldn't want any leaky connections, then... s:D :D s:D
oh..I notice from the Honda link that they're using Honda fluid, rather than Toyotas liquid platinum stuff...?
Does this mean that we too can use it, then?
...or is it "untested" over time....?
Any updates on rebuilt pump reliability or whether there is a proven option to trying to track down Toyotas own fluid?
Haven't managed to obtain a decently-priced rack / PS fluid for testing yet: also been quite busy with other stuff (wheel refurbs / setting up studio, etc, etc....!), but still on the "to-do" list.......
I'll post as soon as I have anything definitive....
Quote from: "Dyn-Evo"Here's the beast in question:
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/EHPSPumppn-1.jpg)
Inside the ECU: not worth opening, IMHO...but I needed to know what was in there...!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/InsideECU-1.jpg)
Reservoir removed:
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Resremoved-1.jpg)
Valve removed!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/FlowCVremoved.jpg)
The vane assembly:
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Vanereass.jpg)
A single vane: dead easy to lose, these...!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/avane-1.jpg)
Dirty motor insides...!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Dirtymotorguts-1.jpg)
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Dirtydeps-1.jpg)
Cleaned up!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/Cleaned2-1.jpg)
Vane dis-assembled!
(http://i786.photobucket.com/albums/yy146/Dyn-Evo/disvaneassy.jpg)
The flow control valve is something I did not dissect: it is possible that something in there fails / spring loses tension over time, etc, which could be the root cause of problems.....?
But we need some more detailed info about any (future) failures to really nail this: codes, symptoms of failure, etc.......?
It could be that the cause of problems / failure could be simply down to an over-worn commutator? It certainly is the only thing that shows signs of wear and tear..?
I did not want to pull the motor shaft, as it did not want to comply, and I just got the feeling that I should not be more persistent...... s:wink: :wink: s:wink:
..Didn't want to "break" anything, as it was all going so well......! s:D :D s:D
My p/s pump stopped working so i continued where you left off, appreciate your work Dyn-Evo, it encouraged me to fix mine:
Removed amature and found that the communtator had worne from 25mm to 22.3mm.
So, i had the amature rewound and a new communtator installed ($A140.-) and she's working again. The car has travelled about 165000km.
(http://i498.photobucket.com/albums/rr348/Sepp_album/IMG_0261.jpg)
(http://i498.photobucket.com/albums/rr348/Sepp_album/IMG_0269.jpg)
Used a bit of spring from a seatbelt mechanism to hold the brushes back for re-installing the amature:
(http://i498.photobucket.com/albums/rr348/Sepp_album/IMG_0270.jpg)
(http://i498.photobucket.com/albums/rr348/Sepp_album/psteeringpumpparts.jpg)
Sepp
Nice work!
Yeh..I didn't have the tools to do the commutator: even though it is worn, if the brushes are relatively long, and in good condition, the motor should still work ok.
But, yes: an ideal refurb will consist of cleaning all the dust out thoroughly, replacing the commutator and brushes, checking the operation of the sliding vanes, and replacing the PS fluid with the proper Toyota stuff.
That should restore the unit to 100% operational spec...! s:D :D s:D
Bought the Gasket Kit from Toyota. Expensive, but i was curious and it will save me frum hunting for the right size ones should i ever need to.
(http://i498.photobucket.com/albums/rr348/Sepp_album/toyotapstgaskets.jpg)
Has anyone found a guide for removing the motor head as i want to check for dust etc in mine. Joke for 18k miles got a humming already.
Dyn-Evo, I think you're my favourite person here s:D :D s:D
What happened to the V6 though? Sad times s:( :( s:(
I sold the V6 about a year ago, so unfortunately will not be doing any more EHPS-related work....... s:wink: :wink: s:wink:
I have now got a Corolla T-Sport Compressor, which I'm starting to like...A LOT..! s:lol: :lol: s:lol:
I have luggage space......!
Room for passengers...! (note: plural!)
I have a supercharger! Even though TTE's implementation of this is not as good as the SC12 fitted to the 4AGZE I used to have..... s:? :? s:?
Its basically very similar to the facelift 6-speed MR2's, spec-wise...?
I think I could squeeze 240hp out of it without spending too much, tbh...?
If I can ever be arsed, that is...! I'm just enjoying driving it....... s:lol: :lol: s:lol:
Hows tricks with you...? s:D :D s:D