R32 Heavy Power Steering - How To Disable Speed Variable Assist Steering And Control Power Assistance Level.

[Ryno]

I've been asked to do a DIY on this simple fix to problems with the R32 Power Steering Assistance.

Issue: After removing HICAS and installing a RB25DET engine in my R32 Skyline, the power steering computer no longer receives a speed input and puts the power steering into fail mode, which causes heavy steering approximately 30 seconds after you start driving.

Tools Needed: Multimeter, Soldering iron and solder, Approximately 2m of wire, heat shrink, DC/DC Converter. Some basic electrical knowledge.

Time to complete job: 1-2 hours.

How the R32 Power Steering System Operates: The HICAS computer in the car alters the input voltage (depending on the vehicle speed) to the solenoid on the power steering rack. The solenoid has two wires going in, a voltage feed and an earth. The solenoid gives max assistance at 12 volts and the assistance reduces as you reduce the voltage. If you have a way to manually control this voltage level, you can adjust the voltage as required to give you the desired steering assistance. You don’t want to just wire in a 12 volt ignition feed direct to the solenoid as this would make the steering dangerously light at higher speeds and probably burn out the power steering solenoid over time.
See picture below to identify the power steering solenoid.

You will need to purchase a DC/DC Converter to allow you to manually reduce the voltage from a 12 volt (ignition feed). I purchased the below unit from Jay Car for around $20.

The plug near the fuse box in this picture has the two wires coming from the power steering solenoid.

Use a multimeter to identify which wire is the earth and which is the feed. Because I'm fussy and don't like seeing dodgy wiring, I lifted the fuse box and traced back the wiring 10 cm, so that my modification to the loom would be hidden under the fuse box. Leave the earth wire intact and cut the feed wire, then solder your length of wire to this and run it back inside the car through the port on the drivers side.

This wire gets soldered to the output voltage of the DC/DC converter. You will just need to locate an earth and an ignition feed under the steering column for the two inputs. Here is me testing the output voltage of the DC/DC converter:

The metal plate on the top of the DC/DC converter acts as a heat sink. The more effectively the heat sink works, the higher the current (at the set voltage) it can output. With that in mind I riveted the heat sink to a piece of aluminium and then used this as the bracket to bolt it in place. The idea being, that some of the heat will conduct to the chassis of the car and provide a higher and more stable current output.

This should fix your power steering problems! I have found I like the setting at around 8 volts - it seems to give a nice level of assistance at low speeds, without being too light at high speeds.

Of note: Make sure you connect the voltage input to the DC/DC converter from an ignition feed, if you use a live battery feed, it will drain your battery and probably burn out the solenoid as it will be operating all the time (even when the car is off).