heckler Posted May 11, 2009 Share Posted May 11, 2009 Right... I have intermittent PAS, to be honest is quite annoying, especially on roundabouts! - I can be driving along and the PAS will be fine, all of a sudden it stops working, then it will start working again. I can't see any leaks from the rack, the PAS tank is full, and there is flow though the tank. The Pump makes no noise at all. Could it be the solonoid valve jobbie thingy? - Link to comment Share on other sites More sharing options...
stevie_b Posted May 12, 2009 Share Posted May 12, 2009 Could it be the electronics that controls the variation of PAS assistance that's playing up? I guess you've check for fault codes already... Edit: just re-read your post. I'm probably off the mark, but worth a thought anyway... Link to comment Share on other sites More sharing options...
Scott Posted May 12, 2009 Share Posted May 12, 2009 Used to get this problem on the MR2 and it was down to a sticky relay. Quick blast with some WD40 and a damn good shake and all was well again. Might be something similar. Link to comment Share on other sites More sharing options...
Digsy Posted May 12, 2009 Share Posted May 12, 2009 IIRC the MK1 MR2 didn't have PAS. Didn't the MK2 have electric PAS? Heckler: Does the PAS fail completely as in the steering goes unbelievably heavy, or does it just get slightly heavier? If it’s the latter then it would point to something to do with the speed-sensitive wiring. If it’s the former then something else might be happening like a leak past the piston seals inside the rack or a problem with the valve body. I had to drive a 3 series BMW around for a couple of weeks with the PAS disabled. It was amazing how heavy the steering was (PAS racks are geared differently to non PAS racks). Link to comment Share on other sites More sharing options...
Scott Posted May 12, 2009 Share Posted May 12, 2009 Didn't the MK2 have electric PAS? Whats that? Do you mean the pump? If so then yeah i believe the pump was electronically driven. Is the sup ran off of the anc belt? Link to comment Share on other sites More sharing options...
heckler Posted May 12, 2009 Author Share Posted May 12, 2009 IIRC the MK1 MR2 didn't have PAS. Didn't the MK2 have electric PAS? Heckler: Does the PAS fail completely as in the steering goes unbelievably heavy, or does it just get slightly heavier? If it’s the latter then it would point to something to do with the speed-sensitive wiring. If it’s the former then something else might be happening like a leak past the piston seals inside the rack or a problem with the valve body. I had to drive a 3 series BMW around for a couple of weeks with the PAS disabled. It was amazing how heavy the steering was (PAS racks are geared differently to non PAS racks). totally heavy!!! as in no PAS what so ever, driving it just feels slightly heavier than normal, until you come to a stop, then its just like trying to turn the wheels without the engine running! Link to comment Share on other sites More sharing options...
adnanshah247 Posted May 12, 2009 Share Posted May 12, 2009 well i had a PAS fault but i lost it completly because the main pressure pipe blew. check for splits, take it off and bend it and the small slits that your eyes cant see will open. its definately most likely that, when you turn it puts it underpressure causing the hole or slit to open, otherwise theres not much pressure to do that. Link to comment Share on other sites More sharing options...
Digsy Posted May 12, 2009 Share Posted May 12, 2009 Whats that? Do you mean the pump? If so then yeah i believe the pump was electronically driven. Is the sup ran off of the anc belt? Yep the Supra's pump is driven from the accessory belt. Might be worth checking that the belt isnt slipping on the PAS pulley. Heckler mentioned that it seemed to be failing on roundabouts, which is when the load on the PAS pump will be high. Could be a faulty pressure relief valve inside the pump, too, but you can usually hear these when they operate. Link to comment Share on other sites More sharing options...
heckler Posted May 12, 2009 Author Share Posted May 12, 2009 Yep the Supra's pump is driven from the accessory belt. Might be worth checking that the belt isnt slipping on the PAS pulley. Heckler mentioned that it seemed to be failing on roundabouts, which is when the load on the PAS pump will be high. Could be a faulty pressure relief valve inside the pump, too, but you can usually hear these when they operate. that bit was in jest there are no leaks, PAS tank remains full of fluid, there is fliuid flow at all times, and no odd noises. So I think anything mechanical can be rulled out, wich goes back to your original idea of the electrical side of the system Link to comment Share on other sites More sharing options...
Digsy Posted May 12, 2009 Share Posted May 12, 2009 What you need is an electrical engineer Thing is that I don't think there's an operating mode for the PAS pump that would result in no PAS at all. I thought it was just "high or low" depending on speed. There is an electrical connection on the rack itself, but I have no idea what its for. Does it happen at any particular speed, or any particular steering angle? Link to comment Share on other sites More sharing options...
heckler Posted May 12, 2009 Author Share Posted May 12, 2009 What you need is an electrical engineer Thing is that I don't think there's an operating mode for the PAS pump that would result in no PAS at all. I thought it was just "high or low" depending on speed. There is an electrical connection on the rack itself, but I have no idea what its for. Does it happen at any particular speed, or any particular steering angle? oh, hang on, i'm an electrical engineer! no, its totally random. It actually happended when I came up to norwich a week ago, then it started to work again when I left norwich.. at first i thought it was "the norwich" affect, but then its stopped again. Still think its an electrial snag, or the solonoid on the rack... Link to comment Share on other sites More sharing options...
ronttuk Posted May 12, 2009 Share Posted May 12, 2009 Used to get this problem on the MR2 and it was down to a sticky relay. Quick blast with some WD40 and a damn good shake and all was well again. Might be something similar. MR2 has electronic power steering not a fluid one Link to comment Share on other sites More sharing options...
Mike Posted May 12, 2009 Share Posted May 12, 2009 Mine died last year - I just got a complete new unit fitted. Link to comment Share on other sites More sharing options...
heckler Posted May 12, 2009 Author Share Posted May 12, 2009 right, PAS is no longer inttermittent! its just totally packed up! - but still remains with:- re no leaks, PAS tank remains full of fluid, there is fliuid flow at all times, and no odd noises Link to comment Share on other sites More sharing options...
GreaseMonkey Posted May 14, 2009 Share Posted May 14, 2009 This maybe of help: http://www.turbosupras.com/pdfs/JZA80%20TSRM/SR.pdf Check out pages SR55 onward ref the PPS system, as IMO it may be something to do with that. Link to comment Share on other sites More sharing options...
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