Hop off .
:hysterically_laughi:hysterically_laughi
The valves are pulsed by a control pack, lifted quickly and dropped slowly by controlled voltage decay to avoid seat damage. Manually simulating that is going to be hard work. Having said that the diaphragm control valve coil pulled by the compressor relay is energised for extended periods without problems.
ukadamwest
Well-Known Member
if you are thinking about using a p38 air system on another car, you could go for an air lift kit like this AIR LIFT AIR RIDE SUSPENSION KIT MANUAL AIR MANAGMENT SYSTEM PACKAGE 1/4" 27666 | eBay or using spares from air lift to get the system you want
Datatek
Well-Known Member
Really?
Coils are energised using pulse and hold, full voltage to ensure rapid operation folowed by a lower holding voltage.
Yes really. As far as i can see diaphragm valve is pulled by compressor relay at 12 volts. The circuit does not go through the driver pack. What would be the point of cycling the diaphragm valve whilst compressor is running? The corner coils are never held they are pulsed, quick open slow close. That's what the clicking is.
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Datatek
Well-Known Member
Tell me how you can slowly close a solenoid valve?
tomcat59alan
Well-Known Member
op2: it's costing me a fortune and not doing much for my waistline.
ukadamwest
Well-Known Member
Yay ! A Wammers and Datatek dispute..
Yay ! A Wammers and Datatek dispute..
Squidge up you two, make room for me..... :5blurk5:
tomcat59alan
Well-Known Member
Pull up a chair and we can share, mine is toffee coated, wot u got?Yay ! A Wammers and Datatek dispute..
By gradually reducing the voltage so the spring pressure overcomes the pull of the coil. It is done so that the seal does not slam back onto the seat. The four corner valves have much stronger springs than the inlet/exhaust and diaphragm valves do. So the voltage needed to hold them open is greater and would warm the coils, pulsing them overcomes this. Most of the energy supplied to the diaphragm/compressor circuit will be absorbed driving the compressor, but there must be enough available to pull the diaphragm valve because that is controlled by the compressor relay not the driver pack.Rather like the 12 volts to D+ that doesn't pull the fuel pump relay because the energy is being absorbed by the field coils. Remember that one.
Datatek
Well-Known Member
A spring return solenoid valve will remain in the operated position untill the magnetic field reduces to a point where the spring pressure overcomes said field, slowly reducing the voltage will not cause valve to close slowly. The coils do not overheat as full voltage is used to provide a rapid opening pulse, the voltage then drops to the hold level which does not cause over heat, in any case the corner valves don't not stay open for long periods, they adjust the height, close while the ECU reads the new height then pulse again if needed, hence the rapid clicking that can be heard.
Spring return solenoids can be made to shut slowly using modulation, can't see any logic in the driver pack that would allow that. Furthermore, slow closing of the valves would make control of the suspension height a tad difficult as the suspension would continue to move up or down during the closing phase which would be somewhat unpredictable.
You been on Wiki again Keith.
Datatek
Well-Known Member
I don't need to, I assume that's where you get your info. I do have a naked driver pack on the table in front of me though.
tomcat59alan
Well-Known Member
No i get my info from Land rover who know a lot more about how their system works than either of us.
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Datatek
Well-Known Member
So you tell me whats inside the driver pack smart arse.
You don't believe LR when they state the MAF controls fueling, bit selective in your beliefs aren't you
Maybe they should have employed you to design the system i am sure it would be faultless. The MAF DOES NOT control fueling it cannot on a diesel engine. If you knew half as much as you think you know, that would be bloody obvious to you. The MAF is there to control the EGR, if it malfunctions it can effect the ECU by causing it to misinterpret air conditions but it does not control fueling. BMW say that, argue with them. I incidentally electrical noise from the driver pack does not cause the false constantly high/constantly low pressure switch fault either.
