Power steering becomes heavy after re-starting engine

[Murray_Calavera]

Hi All,

I have an issue with my power steering becoming heavy in my r33gtst. It only does it under these exact conditions - 

The car is driven from cold and brought up to normal operating temp. The engine is turned off for at least 5 or so minutes. When the engine is turned on again, the power steering is heavy. Sometimes it never goes back to normal, usually it goes back to normal after 20 to 30 minutes of driving, rarely it goes back to normal after a couple of minutes of driving. A typical situation of this issue popping up is refueling at a servo. 

When the car is started from cold and driven, you can drive for hours and the power steering is always perfect. I've done 100's of kilometres and provided the engine is never turned off, the power steering is fine. 

I don't know exactly how long the car needs to sit before the issue sorts itself out, however after the car has sat overnight, it is always perfect in the morning. 

Turning the car off and quickly back on never causes the power steering issue to pop up. 

While the power steering has been heavy, I've thrown the laptop on the Haltech and checked if the ECU was getting a power steering signal - looks like the signal is fine. 

I'm not sure where to start trouble shooting from here so any advice is much appreciated. 

[joshuaho96]

https://www.gtrusablog.com/2017/05/nissan-skyline-power-steering-system.html

Might be power steering solenoid? Also check your HICAS control unit capacitors. I would probably start with the HICAS unit, then check the solenoid. Capacitors in a car this old are almost certainly dying.

 

 

[Murray_Calavera]

Your google-fu is stronger then mine. I couldn't find anything similar to my issue when searching. 

Thanks for finding this for me, I'll give it a crack and see how I go. 

[GTSBoy]

I would suspect heat soak into the solenoid before all other issues. It sounds like a heat soak issue - the sort of thing that only occurs when you get it hot and then stop the car moving, so there's no cooling air over the suspect part. In this case the solenoid.

Of course, it could be just about anything else. When my power steering went (permanently) heavy it was because the O2 sensor heater element burnt up the loom!

[Murray_Calavera]

Yep makes sense, I'll start there.

Is the solenoid a non-servicable item? I've been googling for ages and staring at steering rack parts diagrams on jp-carparts.com, I can't find the part. 

Surely you don't replace the entire power steering assembly if the solenoid fails? 

[GTSBoy]

Dunno. Never had to think about it.

[joshuaho96]

11 hours ago, Murray_Calavera said:

Yep makes sense, I'll start there.

Is the solenoid a non-servicable item? I've been googling for ages and staring at steering rack parts diagrams on jp-carparts.com, I can't find the part. 

Surely you don't replace the entire power steering assembly if the solenoid fails? 

I don't know the exact details of your GTS25t, for some reason though in the 1993-1996 GTS25t it shows the power steering solenoid at the rack as a single part: https://nissan.epc-data.com/skyline/ecr33/3898-rb25det/trans/492/49361/

On the BCNR33 it's a separate part from the housing that you can remove that is somehow triple the price because GTR tax: https://nissan.epc-data.com/skyline/bcnr33/3935-rb26dett/trans/492/49810/

[Murray_Calavera]

Yep, that's what I was looking at. I still can't believe the solenoid is a non-serviceable item. 

Fingers crossed it turns out to be the HICAS ECU. 

[GTofuS-T]

I assume you've checked the actual fluid?

[Murray_Calavera]

Yep, no issues with fluid level. 

And I've checked the solenoid... Makes sense why there is no part number ...