Air suspension pump running continuously

[Silenceisgolden]

The other day my air suspension pump started running continuously, except while the vehicle was lowering. As soon as the vehicle stabilised at the set height, the pump started up again.

I made the 700 kilometre trip to my dealer and they replaced the pump and relay. I asked for an explanation, and was told that my car, 2011 D4, had the Hitachi pump that was unreliable, so they fitted the current type pump and all was well.

However, when I arrived home, I noticed that the pump was in fact still running. So now I have to make another 700 kilometre trip.

My question is this - my new pump was running all the way home, about 12 hours. As the pump would notrmally only run for a couple of minutes at a time, has this long run caused excessive wear to the pump? Should I have it replaced while I am in Melbourne? The cost of a 1400 kilometre round trip, with accommodation, to replace the pump at a later date probably costs more than a pump.

Thanks for any advice.

[Fatso]

Suspect there is/was an air leak somewhere , if they say the older pump was suspect then they have created another air leak fitting the new compressor .
In either case they should be paying 4 inconvenience of not effecting a good repaire .

[Silenceisgolden]

Suspect there is/was an air leak somewhere , if they say the older pump was suspect then they have created another air leak fitting the new compressor .
In either case they should be paying 4 inconvenience of not effecting a good repaire .

Thanks for the reply. Yes, they should pay for the inconvenience but I doubt if they will.

I am still not sure if I should demand a new pump - is it likely that the pump they fitted would be degraded after 12 hours continuous running?

[BobD]

How do you know the pump is running? From the noise or what? Is the car low or does it go down when stopped?


I thought you would get an error message that the pump was overheated if it ran for so long. Mine does if I raise or lower the suspension too much.


Bob

[Silenceisgolden]

Bob, I can hear the pump, but normally only when stationary. The original pump I could hear while on the move, but the new pump is quieter and on the move noise mostly drowns it out.

There have been no error mesages, except when I pulled the 60A fuse before heading to Melbourne.

The suspension does not sink at all. I drove it for three days without the fuse, and it stayed at normal height.

[BobD]

Can you raise and lower the suspension OK? If there is a leak as bad as you are talking about on the compressor side of the valves it would be difficult to get enough pressure to raise it I would think.


Bob

[Graeme]

Does the compressor run continuously if the vehicle is left idling for 5 minutes? When driving the airsprings are constantly monitored and adjustments made to heights which requires the compressor to be run occasionally so it running as you stop is not unusual unless it keeps going when the ignition is switched off.

If its always running and there is no leak then the mechanical pressure relief valve should cycle releasing a burst of air which will be much louder than the normal release of air that occurs when the vehicle is lowered. If the mechanical valve isn't working then an airline will burst which obviously hasn't occurred.

If there is a leak between the compressor and the front or rear valve block then a fault will occur due to the reservoir pressure rising too slowly once the vehicle is up to height.

Confirm with the dealer that the relay was replaced. Its part of the upgrade kit so should have been replaced.

[Silenceisgolden]

Does the compressor run continuously if the vehicle is left idling for 5 minutes?

No, Graeme, it stops after about two minutes. I hadn't tried that before - I assumed that once the bags were up to height, the compressor should stop straight away. Could it be stopping after two minutes because it is over temperature? Is there a reservoir that could explain the two minutes running after height is reached?



Can you raise and lower the suspension OK? If there is a leak as bad as you are talking about on the compressor side of the valves it would be difficult to get enough pressure to raise it I would think.
BobBob, this morning the suspension raises and lowers perfectly. Yesterday it was very slow to rise, and gave occasional messages on the dash saying "Vehicle is rising" or words to that effect.

Thanks both for your help.

[BobD]

There is an air reservoir on the LH side next to the chassis rail. When raising the air in the reservoir is used for quick movement and then things happen more slowly once the pressure drops and air is supplied by the compressor alone. The compressor keeps running to top up the reservoir.


It sounds like your compressor is not running continuously, which is why I was asking earlier what was making you think that it was running continuously. The car is always making adjustments to the suspension and the compressor will work occasionally to keep the reservoir topped up.


Graeme has good knowledge of all this stuff since he invented the Llams system!


Bob

[Silenceisgolden]

Thanks gents,

I see now that there really is no problem. I had never realised that the pump would continue to run after correct height was reached - instead I paniced and pulled the fuse when the pump didn't stop.

Now that I know there is a reservoir, it all makes sense. It was slow to rise yesterday because the reservoir was empty - I replaced the fuse, started up and immediately hit the "Rise" button.

Today the reservoir was full, and it raised normally.

Thanks again, again the forum to the rescue!

Cheers.

[101RRS]

Thanks gents,

I see now that there really is no problem.

And probably was never a problem though upgrading the compressor from the Hitachi to the AMK is probably a good thing. Just may not have been needed at the time - maybe was needed.

[Silenceisgolden]

And probably was never a problem though upgrading the compressor from the Hitachi to the AMK is probably a good thing. Just may not have been needed at the time - maybe was needed.

It was a problem first time around. The compressor ran nonstop for nearly half an hour until I could find a spot to stop, and it made a rather nasty noise. Normally I wouldn't have heard the compressor while driving but this became very loud. This event was why I listened carefully to the new one.

[Epic pooh]

That's the sort of behaviour I was getting out of my hitachi before I turfed it - noisy and running too long. The AMK is a great improvement and I'm happy I changed to it before the hitachi gave me any real grief.