Compressor always running…. And me running out of ideas

Hi guys,



Could you please help me once again?
My compressor runs almost continuously. When it does stop there is a quick puff of air in the vicinity of the exhaust valve then after a couple of seconds the compressor starts up again and keeps going until the next puff of air. Sometime you can hear valves clicking while driving.


When maneuvering in the garage and pressing the brake I can feel a small vibration in the cabin. When I release the brake pedal I can see the front of the car rising 1 or 2 cm, the vibration disappear immediately and the compressor shuts down for a while and then comes up again. I can see the car rising looking the light beams on the wall of the garage (I think it’s the front rising but could also be the rear dropping ).


The car doesn’t drops at night at all.


A couple of months ago I renewed the valve block, 2 front bags, drive pack and pressure switch as I was getting a pressure constantly high fault code.


Since I didn’t have any eas fault. Everything fine.But compressor always running.


I changed relay 20: nothing.
I changed the seal, o-rings and the ring in the compressor. The car rise in 10 minutes after having depressurized the systems. All high changes are made immediately and smooth.
No air coming out when system running if you unscrew the silencer.


Why is the compressor continuously running and the car making small adjustments when you depress the brake?


I’m running out of ideas on this one. I’m starting to think the EAS ECU or a high sensor to blame. But I don’t get any high sensor faults and the highs read with the software are OK.


Any ideas? Compressor? ECU with bad earth? High sensors?
Any input to understand what’s going on would be much appreciated.

You have an air leak somewhere.

Thanks Wammers. But where then?
As it doesn’t drop even 1 cm in 24 hours the bags are now OK.
Then it must be the connection to the air reservoir or the reservoir itself. I sprayed it with soapy water but no joy.
Could it be the pipes coming/going from the air dryer? The blue pipe going from the compressor to the valve block? The compressor itself?
I can’t remember if it were you or Data no excluding a bad earth problem in a old tread with similar symptoms (pump running when braking).

Could be leaking through NRV1(?) or the diaphram valve in the block.

The re-leveling after brake application is the system adjusting after a nose down event (braking), also the system does self level on the move...

NicP38 said:

Thanks Wammers. But where then?
As it doesn’t drop even 1 cm in 24 hours the bags are now OK.
Then it must be the connection to the air reservoir or the reservoir itself. I sprayed it with soapy water but no joy.
Could it be the pipes coming/going from the air dryer? The blue pipe going from the compressor to the valve block? The compressor itself?
I can’t remember if it were you or Data no excluding a bad earth problem in a old tread with similar symptoms (pump running when braking).

Click to expand...

There is no pressure in the airdrier pipes unless the system is being filled or exhausted. The blue pipe goes to the R/R airspring. It's the Violet pipe that goes to the tank.

wammers said:

There is no pressure in the airdrier pipes unless the system is being filled or exhausted. The blue pipe goes to the R/R airspring. It's the Violet pipe that goes to the tank.

Click to expand...

Sorry I was thinking about the blu pipe going from the compressor to the valve block.

Saint.V8 said:

Could be leaking through NRV1(?) or the diaphram valve in the block.

The re-leveling after brake application is the system adjusting after a nose down event (braking), also the system does self level on the move...

Click to expand...

Thanks Saint.

I renewed the valve block few months ago. This doesn't mean all o-rings and diaphragm have been perfectly replaced. Could be worth stripping it down once again and check. especially if you guys don't think the problem could be something else as a leak.

Silly question but I prefer to ask before doing something stupid and get crushed under the car. I would like to check for leaks the eas pipes going to the reservoir and the reservoir itself. Now if I depressurize the whole system I would not be able to crawl under the Rangie anymore.

In the eas software you can choose between depressurizing the springs or the tank. Now my question: If I depressurize only the tank with airbags on high profile and then I disconnect the pipe going in the tank would the car drop?

The idea is to depressurize the tank and than start the engine and let the compressor fill the tank with me under the car looking for leaks there.

It shouldn't aslong as there is no leak in the system....

In theory the pressure in the srpings is held on the associated valves in the valve block, so disconnection of the tank pipe should have no effect on the springs....

If you are checking for leaks, I don't understand your need to empty the tank or even disconnect it, if there is no air in it how can you tell if it is leaking??

Never crawl under an unsupported EAS car even if all the wheels are still on the ground if a bag bursts, it would be curtains time....

If you are looking for a leaky bag, raise to high, put axle stands under the chassis rails but about an inch below, leave a door or the tail gate open, then you can check the bags. Leaving the door open will disable the self leveling, and the axle stands are there to catch the car should it start dropping, and will stop it before it crushes whomever is underneath.

Thank you Saint.

You scared me enough. I wont crawl under the car.
The car doesn't drop during the night but when driving the compressor is always running. So I'm looking for leaks. The pipe going to the reservoir doesn't leak at the valve block. I want to check if it's leaking where it goes in the reservoir. Last time when the system were re-pressurizing after I depressurized it I could ear an hissing noise coming from under the car. It's not normal isn't it? So I thought I'd have a look at the reservoir while is pressurizing. This is the reason for me wanting an empty tank and at the same time being able to have a look under the car.

would a constant running compressor reduce mpg?

jamesblake said:

would a constant running compressor reduce mpg?

Click to expand...

Not noticably.

Cheers!

Just eliminating things....

Had this problem once after I re-built my valve block.
The suspension would drop no more than 1cm all round if I pulled the EAS relay under the passenger seat or disconnected the battery.
Yet, the compressor would keep running until the EAS went faulted and beeped at me.

No leaks at the air springs, and eventually turned out to be a crimped o-ring on one of the front solenoids. This is the really fine o-ring that seals the solenoid stem.

On another note, the EAS compressor stops running under one of 3 conditions:
1) It senses an over pressure condition (145psi/10bar ???) triggered by the pressure switch on the underside of the valve block.
2) The compressor overheats, triggered by the thermal switch in the compressor at above 120C.
3) A fault flagged by the EAS system.

I believe the pressure switch is NO (someone please correct me if I am wrong). If it's an NO switch, shorting the terminals together should stop the compressor. Perhaps you should do this check first, and go on from there.