Which valve?
Which valve?
tomcat59alan
Well-Known Member
No need to. Exhaust silencer can get blocked that is true but it cannot effect the readings from the pressure sensor which is beyond NRV1.
OK completely block one up and see what happens.
If it is completely blocked it will prevent air from escaping when the bags are vented on height change to a lower setting. Or it will prevent air being vented as the compressor stops and the diaphragm valve is depressurised. It CANNOT effect the pressure switch which is as i said earlier beyond NRV1.
Any of them. The driver pack can cause all sorts of problems as they are getting old and in the hot area they live can fail. They are after all a simple amplifier to drive the solenoids. Unfortunately they can't be repaired and checking them involves an oscilloscope.
If your car starts moving up and down whilst at the traffic lights the Driver Pack could be playing up. Not always but often it's the problem.
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Datatek
Well-Known Member
You tell me, you're the mechanical expert, I'm just speculating as I know what dodgy MOSFET's can do.
Datatek
Well-Known Member
They can be repaired and they are not simple. De-potting them is a tad boring though.
Never tried to repair one, didn't think it was possible. Did you succeed in a repair?
Yes that is correct but which valve would the driver pack effect to give an incorrect pressure reading?
But how does the driver pack effect anything other than the valves it operates? It certainly cannot effect the diaphragm valve and has no connection at all to the pressure switch.
Datatek
Well-Known Member
Maybe a fluttering valve causes pressure loss.
That could be it. I don't think any of us knows for shure but if the Driver Pack has a fizzzy (or several) and sends some signals that have not beeen commanded to say several air spring solenoids (remembering that under normal surcumstanses the inlet or exhaust valve must be energised together with the relevant air spring solenoid valve) there could be a scenairo where the ECU has not made a command (it has no memory as to whether its command has been actioned) and a low pressure situation happens before the ECU control relay can switch on the compressor but too late to prevent a fault or spurious action especially if the pump is weak?
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The compressor would have to be stopped for that to happen, air cannot be exhausted whilst the compressor is active. The driver pack cannot cause air loss with the compressor running. The diaphragm solenoid that shuts the exhaust port off by applying air pressure below the diaphragm to allow compressor to charge the system is pulled by the compressor relay. So the driver pack cannot influence that. Neither can it influence the pressure switch which is not in any way connected to the driver pack. I have no doubt that a duff driver pack maybe can cause valves to be opened randomly, but to expend air from the tank without inflating the bags it would have to open the inlet and exhaust valves at the same time with the compressor inactive. I think the driver pack gets bad press because of poor loom plug contacts in the most part with a few genuine fails thrown in from time to time.
Just to add a bit, I definitely found Driver Pack causing EAS weirdness.
Pete
- Original pack has bad joint where the wiring enters the compound. Still slowly de-potting it to see if I can fix the dry joints.
- Replacement seemed to work ok initially, but was intermittent after a few days. Finally found the fault, which was the sockets inside the connector between the driver pack and solenoids (C139 & C140 in Rave). Tightened all 12 of them individually, and now the solenoids operate when told to !!
Pete
Datatek
Well-Known Member
I had EAS connector problems when I first got my P38, this time only changing the driver pack cured the problem. Duff MOSFETS could certainly produce the same effects as faulty connections.
Could they cause feedback into the ECU and effect circuits not normally anything to do with the driver pack?
