S

srijken

New Member
I'm investigating a problem in 2 different P38s, which seems to be a pretty similar problem.

The first one had leaky bags, and has had the compressor replaced (probably because of the leak combined with 160k miles). Now the compressor doesn't stay off, runs every minute or so. The front of the car is moving up and down by about half an inch. When it's going down, I can hear the valve block click, which indicates (I think) that the computer is causing the front to go down. When I open the door, this moving up and down stops, and the compressor stays off.

The other one has the same symptom (clicking valves when going down), but when I open the door, it keeps pumping continuously. This is *just* after replacing the compressor unit, so could it be that the air tank has to fill up? Is it expected behavior that the compressor pumps continuously with the door open and at intervals with the door closed, when the tank is empty?
 
srijken said:
I'm investigating a problem in 2 different P38s, which seems to be a pretty similar problem.

The first one had leaky bags, and has had the compressor replaced (probably because of the leak combined with 160k miles). Now the compressor doesn't stay off, runs every minute or so. The front of the car is moving up and down by about half an inch. When it's going down, I can hear the valve block click, which indicates (I think) that the computer is causing the front to go down. When I open the door, this moving up and down stops, and the compressor stays off.

The other one has the same symptom (clicking valves when going down), but when I open the door, it keeps pumping continuously. This is *just* after replacing the compressor unit, so could it be that the air tank has to fill up? Is it expected behavior that the compressor pumps continuously with the door open and at intervals with the door closed, when the tank is empty?
Click to expand...

In the late classic, which is almost identical, the pump is not isolated by door open or closed, just the solenoid block is shut off. so all being = would say its OK. Pump continuously because possible registering a pressure drop in valve block, maybe a shagged O-ring or Diaphragm somewhere.
 
I still suspect that on the first one I described something's wrong with the ride height sensors, because it *actively* changes the ride height on the front. Opening the door indeed shuts off the valve block, and then the up and down action stops...
 
Great site thanks for that.

Does anybody know wether the EAS Unlock software allows calibration of new ride height sensors, and detection of broken ones other than EAS Faults (like non-stable readings)?
 
srijken said:
Great site thanks for that.

Does anybody know wether the EAS Unlock software allows calibration of new ride height sensors, and detection of broken ones other than EAS Faults (like non-stable readings)?
Click to expand...

Yes it does.
 
I looked closer with the EAS Unlock utility. There was a calibration problem, the front sensors indicated the same height, but the system was calibrated for unequal sensor reading. After fixing that, the up and down motion was reduced a lot.

No EAS faults appeared, except the "vehicle has moved" message.

All springs remain at the same height, ie valves closed, except the front left one. The front left spring goes up and down by about 3mm.

Does this up and down motion of one corner indicate an unstable sensor reading, or are there other causes for behavior like this?
 
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