q45tech: question on consult active test

[1992Q45A]

Q45tech,

I think I heard you mention before the consult test on the active suspension is fairly intensive.. Runs through the whole system, takes a good deal of time to run through..

I assume this is the diag mentioned in the FSM under the active suspension section. Mentions two ways to check, the height switch way (adjust 10 times in 10 seconds or something) and then the consult test..

Do you know if the consult test reads how much charge is left in each of the actuators?

Thanks

[Q45tech]

There is no nitrogen pressure measuring system on Q just fluid pressures.Pretty much known fact that accums must be recharged every 60-75k or 4-5 years...........obviously even at 30k or 2 years the pressure is lower..........progressive decline from perfection.Obviously this would depend on temperatures and road roughness - strokes per mile.

We did a Texasoil 9 accum exchange about 3 years ago the system still seems very good after 25,000 miles but the owner doesn't drive this car that much.

He is hoping to get another 25-35,000 miles before doing it again.

[1992Q45A]

Thanks for the info. I'm just going to assume these actuators are flat. Why else would the car sit so low, when the system is off.

I seem to be getting conflicting information regarding the system bleeding pressure, when it's not in use. I've been told it doesn't lose charge when not being used, but I've also been told the opposite.

You have any insight on this?

[Q45tech]

Flat [low nitrogen pressure] won't affect ride height even 1/2".*

The springs are 75% of standard Q [108 vs 146 front].........my guess is that ~~ 350 lbs + of upward force [not sure how to translate this into strut psi--Area of piston] is needed to raise the ride height to normal.

* From my observing many flat Q.

[azskygod]

An extremely low fluid level will cause an active Q to ride low and hard, bouncy even. I've personally experienced this on at least one occasion. The difference in ride quality between low fluid and full fluid levels (regardless of accumulator charge) is like night and day.

Q45TECH is correct -- accumulator charge has absolutely no effect on ride height. The only way to determine the condition of the wheel accumulators is to perform the corner bounce test. No rebound = flat accumulators.

Also, a bad active suspension controller will cause the suspension to bottom out and ride on the bump stops with zero support from the hydraulics. I repaired mine after finding a cold solder joint on the PCB connector inside the controller -- very similar to the fuel pump controller overheating problem. It has been working fine for the last 50k miles.

Let me know if you need any help...

AZSKYGOD

[1992Q45A]

I had the link somewhere, but I can't seem to find it...

Anyway, the toyota has this diag test you can run on it, and it literally does a dance!! It's like a low rider at a stop light, each wheel does some sort of test checking for how much play is left in the suspension...

It's really neet, espically considering you can do it yourself

I wish we could do this.

[texasoil]

The Q45a WILL settle about 1/2-1" when the engine is shut off. IF everything is absolutely perfect, it is 'supposed' to take about 7-10 days for this to happen. With flat main accumulators it takes just a few minutes to hours. There is ALWAYS a slight 'jump' after shutting off the engine. It may take as long as a minute--depending on the load in the car (higher load takes longer)This 'jump' may not even be apparent, or it may be as much as one inch--and could be either up or down, depending on temperature difference front to rear and load distribution. Later cars (94-95) had a modified rear control valve (which Infiniti would retrofit if customers complained about the 'jump') to reduce this effect--which has to do with strut pressures equalizing and then the main pressure valve opening.

Nitrogen charge pressure in the strut accumulators does not effect operating ride height. It definitely effects standing settle -out height. Charge pressure in the man accumulators will also effect standing settle-out height.

[1992Q45A]

Any other changes to the active ECU/setup between model years?

I also sent you an email regarding your recharge services.

[texasoil]

please resend email to [email protected] I haven't seen it. MNN (Hotmail) got bombed this weekend with some kind of spam virus

[1992Q45A]

sent