I've recently deleted my HICAS and only just now put the car back on its wheels and started it to turn it around in my garage. So this is the first time since the delete.

I now seem to have no power steering at all. The HICAS light is illuminated but I expected that and I believe there is a wire snip fix for that light, which I was going to do later on? As far as I was aware this wouldn't cause loss of power steering?

I have deleted the solenoid completely though and used the common fixing to loop the lines in the engine bay. Are there some additional steps when deleting the solenoid?

 

Is the HICAS control unit plugged in to the harness?

1 minute ago, AndrewG said:

Is the HICAS control unit plugged in to the harness?

Currently, yes. Both connectors are connected to the HICAS control unit. I have seen some chat about fixing the HICAS light but retaining PS fluid warnings by disconnecting one of the two connectors - I think the smaller one? I have not seen anyone mention failure to do this would cause no power steering though. I plan to try that this week though in the hopes it may fix my problem. 

Just tried with the smaller connector unplugged and this did stop the HICAS light but didn't make a difference to the power steering.

I should also add that it's not no PS at all, like I first said and assumed. I wasn't really concentrating on diagnosing this at the weekend - more getting the car turned around. It's easier to turn than with the engine off... But very heavy. 

 

Sorry if it's a daft question, but, have you bled the system fully?  I'm guessing you might not have with it being the first start 

1 hour ago, bird said:

Sorry if it's a daft question, but, have you bled the system fully?  I'm guessing you might not have with it being the first start 

Not daft at all as I was wondering the same thing. I did some bleeding before turning it around. I have since done a whole lot more again, both my turning the steering wheel and then forcing the wheels lock to lock rapidly by holding the wheels themselves. I noticed no air when doing the method holding the wheels themselves, just surging and some overflowing of fluid from the reservoir when really pumping the wheel.

I won't know whether the extra bleed has helped until the wheels are back on the ground. I have some other bits I need to get sorted before that happens though. Fingers crossed.

 

Do let us know.  You should have replaced the copper washers but maybe check theres no leaks.  Also that the belt on the pump is tightened right if you've had it off 

The air in there can be really stubborn, especially if you fully drained the system.

I don’t recall making any changes to the wiring on mine, the reason I get the hicas fault light is if the fluid is low. That or when my Speedo used to fail. 

You have definitely connected the short link correctly? 

I dropped it back onto its wheels today but still the same symptoms. This was after a whole bunch of extra bleeding too. 

I have double checked the HICAS bypass fitting and all seems well there. 

I am wondering if it's in failsafe mode as per the workshop manual which results in "heavy steering operation". Apparently it will drop into this if any of the following are not being fed correctly to the power steering controller: speed sensor, foot brake signal, parking brake signal & neutral position switch.

I was hoping free Conzult would tell me the status of these this but all those things are greyed out so looks like I'll need the paid version. 

Does anyone know the best way to get a license for Conzult these days? 

Edited May 8, 20223 yr by Peage

You can put the HICAS into diagnostics without a ConZult. It is described in the FSM (ST section Trouble Diagnostics)

and also here:

http://www.ttzd.com/tech/hicastech.html

I've not tried this method though.

Thanks Andrew. I've just realised actually that the failsafe valve is at the rear of the car so as I have bypassed the lines the to rear, it's impossible for the car to go into failsafe? So I am dropping that idea for now.

Is it notchy when you turn or just heavy?

40 minutes ago, bird said:

Is it notchy when you turn or just heavy?

Just heavy. Not noticing any notchiness to it.

Really scratching my head with it now!

 

Did you use the right fluid?  Its automatic transmission fluid in these.  Dextron 

Yes definitely used ATF to fill it up. More of the same of what was in there prior to the delete.

I am now wondering whether it is just the pump has a problem and needs replacement. 

Is the HICAS light on? 
 

The float switch connection on the cap can get damaged. If the lights on then either the speed sensor is causing issue or the fluid level isn’t showing properly. 
 

It’s got to be something silly if it worked before. 

The HICAS light is on unless I disconnect the smaller HICAS connector on the control module but I understood that was normal when deleting the HICAS solenoid and it would illuminate in the case of low fluid at the reservoir with the HICAS connector disconnect - which it does not. I assume from that the float switch is okay. 

I was thinking similar that it must be something else but also have a nagging thought the pump died from iffy bleeding initially and then running the engine up... Not sure. The pump had its noisy moments in the past but has always functioned.

Ok so I purchased Datascan to get more info on the sensors and power steering related items. All the relevant sensors are reporting in okay and seem to be functional. I had a question around the power steering solenoid though. My outputs are below:

Engine Off:

Engine On:

I don't really know what the metric is for the power steering solenoid value. I was wondering if anyone knew whether 1.05 for engine off and falling to 0.25 at engine on and stationery is normal?

 

On 09/05/2022 at 14:49, Peage said:

Ok so I purchased Datascan to get more info on the sensors and power steering related items. All the relevant sensors are reporting in okay and seem to be functional. I had a question around the power steering solenoid though. My outputs are below:

Engine Off:

Engine On:

I don't really know what the metric is for the power steering solenoid value. I was wondering if anyone knew whether 1.05 for engine off and falling to 0.25 at engine on and stationery is normal?

 

Hey Peage I have recently deleted my hicas in my 1991 tt z32 and am having the same hard steering issues. I was wondering what ended up being the fix to your issue, if fixed?

I have not confirmed a fix yet. I ended up buying a refreshed power steering pump but have not yet had the car down on its wheels and running again as I have been working through some other bits on the car like dropping the fuel tank, replacing fuel lines, refreshing upper control arms, etc, etc, etc. The new pump is fitted and will probably be tested in the next week or two. 

How did you perform the delete, was it the same as me? I deleted the HICAS solenoid along with removing the rear rack.

On 11/07/2022 at 02:53, Remy said:

Hey Peage I have recently deleted my hicas in my 1991 tt z32 and am having the same hard steering issues. I was wondering what ended up being the fix to your issue, if fixed?

Just to report back in on this - in my case the pump replacement seems to have resolved the issue. 

Just reporting back in on this for anyone else who has the issue - seems the resolution was very short lived. It was fine for the first small test drive but has been back to being heavy ever since.

I have since replaced the rack solenoid (resistance tested the old one and it was within spec anyway) and the new solenoid did not resolve the issue. Weirdly after first doing the solenoid, immediately after start up, it was fine for a brief period. After going lock to lock a few more times for bleeding and letting it idle, it went back to very heavy again and has remained that way. 

I now have a power steering high pressure switch to fit. Based on the previous, I assume something is making it drop into failsafe mode and the pressure switch is the last thing to try. Fingers crossed. 

 

Hey there, long time haha. I have spoken to some buddies over time and from what I have found. Swapping to an n/a power steering pump after the hicas delete should fix the hard steering. There’s another post on twin turbo net talking about signalling issues that would also cause the issue. 
http://twinturbo.net/nissan/300zx/forums/technical/view/1164091/Power-steering-assist-speed-signal-and-hard-steering-Long.html

I did actually bite the bullet and convert to an NA pump. Haven't tested it yet but hopefully will get to in the next week or so. Really hoping that solves it as I've changed everything else but the rack itself now near enough! 

Did you ever resolve your issue or is an NA pump next on the list for you too?

I have not yet resolved my issue as I am still on a TT pump, hoping it will go away once I’m able to source and install an n/a pump!🙏🏼

I used and recommend the Z1 kit. It was showing unavailable as it is now but I contacted them and they confirmed they had all the bits needed and created a custom order for me. Might be worth emailing them. Not sure why it's permanently unavailable on their site.

https://www.z1motorsports.com/z1-products/z1-motorsports/z1-300zx-z32-complete-hicas-removal-kit-p-16785.html