NorsemanE320

Hello forum!
I have been searching on several forums including this, but have not found any answer for this problem:
After riding my car it seems to be a bit higher in the front than it was when I started the ride. When i lock my car, or when I unlock it (there seems to be no system of this), the car let out some pressure and the car lower a bit. The lowering prosess take about 20 seconds. I do have it on video, but I`m not allowed to post mp4-files here. Its difficult to tell if the pressure leaks out from the left fron strut or the compressor. I have changed all 4 struts before, and the front dosent lower as much as it did when the strut was broken, it goes back to the level of Sport2 mode. I took the car to the workshop, but there was no error in Star Diagnose System. But, they can see that the compressor rise the car more often than normal. They updated the system, but still the same.

My guess is a faulty hight-sensor or a faulty nozzle, but I find it strange that there are no error-messages.

Suggestions anyone?

bbirdwell

Look into calibrating the air suspension. I've posted on the process several times. Once prepped, takes < one hour to calibrate using STAR.

To check, with the car parked on *an absolutely level* surface (explained in other posts), use an inclinometer (can be a cell phone app). Front control arms (use the nubs) should be +3.1 to +4.1 degrees (inboard higher than outboard). Rear axles should be -0.9 to -1.5 degrees (inboard lower than outboard).

NorsemanE320

thx for a good advice - will ask my workshop to do this.
I guess they know about the procedure. Is it the same degrees on a E320cdi as on a E55AMG?

And besides - is this a common problem? Haven`t found a similar post.

bbirdwell

Once your vehicle is selected in STAR, it will bring up the max/min angle values for front and rear. The ones I quoted are for my E55 but yours should be very close if not identical. After swapping all four air springs and rebuilding my car's suspension, the rear was far too low and the right front was an inch lower than the left front. My car was sitting at -2.8* on each rear axle and a +2.6* and +2.8* on the front control arms. I set it at +3.1 degrees front (lowest height) and -1.2 degrees rear (middle of the height range). For my car, that corrected both an excessive camber issue and got rid of a diagonal "rocking" motion caused by one front axle not equal to the other side.

Look under air suspension or control units, it will be ENR control unit, "Initial startup with manual settings input for new control unit/ Level Calibration". The system will walk your through the process; just be sure to take note of the control arm and axle angles on a piece of paper so you can enter those values manually at the last step of calibration. The system calls for a Romess automated inclinometer that communicates with the system but a cell phone app works fine. Just be sure the floor is absolutely level using floor tiles under the tires where needed. I would place identical sockets at tire locations, place a 6' piece of square tube aluminum on the sockets, set inclinometer on top of the square tubing, then add floor ties under one side or the other until floor is level. Pull the car up, raise/lower a couple of times, then measure the suspension angles. If not within spec, calibrate using STAR.

rodneypierce

You also need to remember that your car will raise a bit when you get out of it as you are removing quite a bit of weight from the drivers seat.

NorsemanE320

Hello again, took my car to the MB workshop. They did a full calibrating, and claims everything was done by the book. Still the same problem, and they still can't tell me whats wrong. Their solution is to change both airsprings, and if thats not helping, they want to change the compressor as well. That will cost a lot more than the value of the car. There is no errormessages, neither on the springs, compressor or the hightsensors. So that leaves me the question; is the exspensive change of springs and maybe compressor the only solution? Or can it be a minor error like a bad connection some place?

bbirdwell

I cannot see the compressor doing this; this is a sensor or control unit issue. Let me think on this one a bit. Anyone else with ideas is free to chime in...

NorsemanE320

Still struggeling with this issue. The latest is, according to the workshop, that it's due to a faulty compressor. A new compressor and labor will charge me for over $1000. I might do this, but will i run any risk if i run my car until the compressor is completely broken?

SLcharge

It has nothing to do with the compressor. that is BS. The compressor supply air to the system, and has nothing to do with the height of the car. It's a passive component.

As others point out, it's a matter of calibration.

Your workshop is obviously not up to the job.

The air release, when you lock and unlock, is normal, or if you have keyless go, and have the key in your pocket, the compressor will start as you open the drivers door, to pump up the system pressure. If the car has sunk, the electronics will raise it to normal level, and the compressor, if okay, will not run for more than 20 sec. If it runs longer than that, it is leaking and will fail at a point. Compressors are know to only last 50.000 miles, and are to be replaced accordingly. The compressor is located inside the front left fender, and easy to access. I bought my last one on Alibaba, and it has so far outperformed any previous MB compressor, and at 1/3 of the price.

NorsemanE320

Thx for your reply. My compressor is from december 2003 and havent been replaced yet. But it still work fine, raising my car from sport 2 to maximum hight in 20-30 seconds. Strangely enough the problem seems to be erased after the work shop replaced å hose in/close to the compressor. Wonder how long it takes before it's back...

Redwood415

has to be related to inaccurate reading from level sensor. Compressor would not cause your issues, they either work or they don't.