P38A EAS question

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rangie1998

rangie1998

Active Member
Posts
279
Location
Leeds
Hi all,
Further to a previous post, still trying to figure out why the compressor is always running!
One question I have, when the suspension is levelling and air is exiting the exhaust should this cause the pressure in the tank to drop?
Thanks
 
rangie1998 said:
Hi all,
Further to a previous post, still trying to figure out why the compressor is always running!
One question I have, when the suspension is levelling and air is exiting the exhaust should this cause the pressure in the tank to drop?
Thanks
Click to expand...
Levelling up or down? If the compressor is running all the time, there is a leak. Tank pressure will drop if the suspension is rising in that situation there should be no air out of the exhaust. If levelling down, there will be air out of the exhaust.
 
Thanks for your reply. Today I connected a pressure guage to the tank line and left a door open. Pressure rose to 145psi and the compressor turned off, no problems. Pressure doesn't drop. Shut the door, car started to rise and pressure dropped to about 110psi.
The compresssor would then keep turning on and off and the pressure was increasing very slowly but not reaching 145.
So, the compressor and the switch work fine with the self levelling disabled but not when it isn't!
Any help would be greatly appreciated, been trying to figure this out for weeks!
PS there are no leaks, car doesn't drop when left for a week.
 
rangie1998 said:
Thanks for your reply. Today I connected a pressure guage to the tank line and left a door open. Pressure rose to 145psi and the compressor turned off, no problems. Pressure doesn't drop. Shut the door, car started to rise and pressure dropped to about 110psi.
The compresssor would then keep turning on and off and the pressure was increasing very slowly but not reaching 145.
So, the compressor and the switch work fine with the self levelling disabled but not when it isn't!
Any help would be greatly appreciated, been trying to figure this out for weeks!
PS there are no leaks, car doesn't drop when left for a week.
Click to expand...
Sounds fairly normal to me, compressor runs in short bursts to prevent overheating.
 
When driving, the compressor is constantly turning on and off. Probably something really simple I just haven't found it yet!
 
The ECU switches the compressor whenever the pressure switch tells the ECU the tank is low. It needs to switch off when lowered because air cannot enter & leave the system at the same time.

So in normal use the ECU will regularly adjust the corners up & down as required. . . . . .means the compressor must switch on & off regularly !!
 
Rubberknees said:
Gee gosh. Thanks teacher. Do I get a star :D
Click to expand...
giphy (1)_75035423209904.gif
🤭
Oh go on then😎👍
 
rangie1998 said:
Thanks for your reply. Today I connected a pressure guage to the tank line and left a door open. Pressure rose to 145psi and the compressor turned off, no problems. Pressure doesn't drop. Shut the door, car started to rise and pressure dropped to about 110psi.
The compresssor would then keep turning on and off and the pressure was increasing very slowly but not reaching 145.
So, the compressor and the switch work fine with the self levelling disabled but not when it isn't!
Any help would be greatly appreciated, been trying to figure this out for weeks!
PS there are no leaks, car doesn't drop when left for a week.
Click to expand...

Sounds good on the pressure side.
Closing the door brings in all the EAS system.
If the compressor continues on/off and the tank doesn't reach the pressure to turn off.
Then I would think you have a leak that the tank/compressor is trying to feed to keep the car at height but cant so the compressor keeps running on/off.

Or you have a problem within the block valves if its exhausting.

Time for the fairy liquid and water spray treatment for me.

Before you burn out the compressor.

J
 
Last edited:
Apologies for late response. I've connected a pressure guage on line 6 to the tank. Pump turns off at 145psi and no pressure drop when left.
When driving, the suspension adjusts and air exits the exhaust, pressure drops in tank but sometimes only to 130psi but pump still starts but stops before 145psi, it continues doing this meaning the pump is nearly always running.
Have 2 spare valve blocks so have tried the pressure switches from those, no difference.
A friend has the faultmate and software. Plugged it in, no errors showing on height sensors and all settings within tolerance.
Drove with it connected, it shows the pressure switch constantly turning on and off, each time turning on the pump.
Could it be a problem with the non return valves?
 
rangie1998 said:
Apologies for late response. I've connected a pressure guage on line 6 to the tank. Pump turns off at 145psi and no pressure drop when left.
When driving, the suspension adjusts and air exits the exhaust, pressure drops in tank but sometimes only to 130psi but pump still starts but stops before 145psi, it continues doing this meaning the pump is nearly always running.
Have 2 spare valve blocks so have tried the pressure switches from those, no difference.
A friend has the faultmate and software. Plugged it in, no errors showing on height sensors and all settings within tolerance.
Drove with it connected, it shows the pressure switch constantly turning on and off, each time turning on the pump.
Could it be a problem with the non return valves?
Click to expand...
As said before, sounds normal to me.
 
rangie1998 said:
Hi, don't think it's normal. Compressor shouldn't be running this much, it's literally running nearly all the time.
Click to expand...
There are only really 2 reason if the compressor is running too often, a leak or a weak compressor. The compressor produces enough pressure to reach the shut off point of the pressure switch and it comes on again as it should when the pressure drops. So if there is a fault, it's that the pressure drops too much when adjusting the height whilst driving. If there is no pressure drop when left, that would seem to rule out the valve block, that leaves air bags leaking as they move. Hidden leaks where the bags fold under are common and left at normal height may not lose air.
 
Datatek said:
There are only really 2 reason if the compressor is running too often, a leak or a weak compressor. The compressor produces enough pressure to reach the shut off point of the pressure switch and it comes on again as it should when the pressure drops. So if there is a fault, it's that the pressure drops too much when adjusting the height whilst driving. If there is no pressure drop when left, that would seem to rule out the valve block, that leaves air bags leaking as they move. Hidden leaks where the bags fold under are common and left at normal height may not lose air.
Click to expand...
Thanks for your reply.
 
Datatek said:
There are only really 2 reason if the compressor is running too often, a leak or a weak compressor. The compressor produces enough pressure to reach the shut off point of the pressure switch and it comes on again as it should when the pressure drops. So if there is a fault, it's that the pressure drops too much when adjusting the height whilst driving. If there is no pressure drop when left, that would seem to rule out the valve block, that leaves air bags leaking as they move. Hidden leaks where the bags fold under are common and left at normal height may not lose air.
Click to expand...
When the suspension is adjusting and vents air through the exhaust should this cause the pressure in the tank to drop? I've read that the compressor shuts off at 145psi and turns on again when pressure has dropped below 104-116psi. Mine is turning on when pressure drops to 135psi.
I have left the car overnight in the 3 different heights and no drop.
Thanks for help so far.
 
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