can be a number of things, but easiest check for now would be to rev the vehicle (on park) to about 2k rpm, then turning the wheel all the way to the left until it locks, then all the way to the right till it locks. repeat it several times. the noise is usually due to air bubbles in the fluid. the pump should eliminate the air bubbles.

If however, this does not solve the problem, you may have a damaged line somewhere causing a leak (which would cause air bubbles as well). in a previous post, you mentioned your vehicle overheating, may have damaged some hoses? anyways, we'll start with the easy stuff first and take it from there.

Need help making power 94tt
 

powersteering is sorted out now.can some one tell me right way to test the viscious fan.car still overheating wen driving hard flushed the radiator with new distilled water.am i supposed to be able to stop the fan with my hand wen she is hot.

Glad your PS is sorted out. What was the issue?

Regarding the fan, I've only ever had one go bad. It made nasty-loud whirring sound and was pretty much frozen stuck solid no matter what temperature the engine was at, but I don't think it was overheating - but I also think the owner never drove it hard with that loud whirring noise (if I recall correctly - it was a number of years back). We replaced the fan's clutch assembly (moved the blades from one to the other), and it fixed the whirring noise.

Is your oem fan shroud still in place? How about the thermostat - is that new? ...and is it oem-spec?

Reminder: No one should ever be doing work on the Mkiv Supra Turbo's powertrain without a copy of the Toyota Supra Repair Manuals (TSRMs). I'm sure there's a test for the fan in the TSRM, as well as a complete diagnostic procedure for overheating.

Need help making power 94tt
 

i drained the powersteering and bled it with new fluids.
oem fan shroud is still in place.took the thermostat out thought it was the fault but it was not that.thermostat is still out. I looked in the TSRM but they dont say anything how to test the fan.
Wen i drive normally the heat gauge is half as soon as i boost her the heat goes up wen i drive normal again the heat goes down.

If I were to guess, it's more likely to be the water pump. However, I agree the fan is a possible suspect as well. At this point, I'd say swap out the fan and if that doesn't fix it maybe Toyota will take it back. Either that, or maybe you can find another MK4 owner that will let you swap his fan for a test...

Need help making power 94tt
 

Im also thinking water pump but not sure.it is a lot of work to change it just on maybe but i take it i dont have a choice.
how is it the pump works fine under normal driving and not under boost.
the heater pipes i blank off at the back off the head that cant be the fault

Need help making power 94tt
 

Could it be the headgasket leaking.it is a new oem one with arp headbolts just wandering

Very unlikely, unless there was a flaw in the head. I once saw a head where the chamber had small chunks of aluminum missing everywhere - of course, they were trying to run high boost on pump gas with a single turbo.

Need help making power 94tt
 

the miss on the car got even worse now it misses wen i just rev her changed plugs did not help going to borrow coils tonight to test.will MSD coils be better to buy for my car and will they work with the oem ecu

No, stick with oem coils. There are a couple other alternatives though:
http://www.superspark.com.au/producttoyota.htm
http://mojoperf.com/drupal/node/15