G50 Suspension dancing!!!

[d3funct]

Hi all,

My 1990 Q is behaving oddly...

The active suspension seems to be buggered, not too sure why..

For starters, the ACTSUS light is on, not immediately, but within 1 minute of driving it, and it stays on.

As you start the car, the act sus raises the car, on all fours... then one by one the shocks "drop" back into 'normal' position...

The suspension itself feels rock solid, like as if it has no travel at all...

Does this sound familiar at all - would it be easier to replace all the shocks and springs with Non-active ones?

Thanks.

[texasoil]

please go to my website 'activesuspensionsystems.com' and read all about the active system.

what you are describing is an unstable system. The control valves wear due to not changing the active oil and keeping it CLEAN. The valve pilots--the device actually moved by the solenoids being controlled by the computer--are force balanced by an adjustable spring.

The entire system is designed so the 'control pressure range' remains constant as the vehicle weight changes (passengers,fuel,etc.). This enables the control valves to be 'pilot actuated' with very small operating force requirements because they can be 'force balanced' with a mechanical spring. When new, height N, driver and full tank of fuel, the solenoid force should be right in the middle, providing the maximum control capability. This is accomplished by carefully adjusting the balance spring (higher or lower force as required) when the valve assembly is manufactured,tested, and calibrated at the factory.

When the valve pilots wear and high pressure fluid 'leaks past' them enough to effect the pressure (height) in a wheel circuit, the solenoid for that wheel has to adjust by changing the force it is exerting. When the solenoid force gets out of range, instability results--the pilot valve admits fluid, the system says stop that- but it still raises the corner!! until the multi-valve senses the increased pressure and raises the control range pressure, which increases the leakage rate which .....etc, etc. and things go rocking and rolling until the fail-safe valve actuates with a CLUNK and dumps the system pressure.

Usually, screwing IN 1/4 to 1/2 turn of the balance spring of the offending wheel will settle things down. Sometimes several wheels have the same problem. It is a 'tweak and test' process, carefully recording your changes so you can 'go back to start'

[Q45tech]

Why Japan has the maintain it like new or junk or export rule.

[elwesso]

one thing it could be is low fluid. Im working on an active right now and I had the same thing happen when it was a tiny bit low on fluid. Id double check that.