P38 EAS constantly adjusting

bstein · Aug 22, 2018

I have searched allover but I can not find an solution to my problem.
-The car is a ´99 P38. When the EAS is in "Standard", "Low" or "Access" mode the EAS is constantly adjusting up and down (1-2cm) and never settling. This causes the compressor to constantly run. When I plug in the Nanocom I can see the valves opening and closing.
When the EAS is in "High" everything is fine and the car stabilizes and the compressor switches off.

-The car will sit for a long amount off time without sinking so I do belive the system is leak free.
-All airsprings new last 12months.
-New valveblock last 12months
-New driverpack last 12months
-All height sensors new last 12months
-Switched with used EAS ECU

Any ideas or suggestions?

brianp38dse · Aug 22, 2018

Are your heights set to within two bits side to side or that will not help.

Datatek · Aug 23, 2018

brianp38dse said:
Are your heights set to within two bits side to side or that will not help.

Set within 2 bits side to side? Where did you get that from? The sensors are not that precise and the readings side to side on a flat level surface with the heights set correctly can be further out than that and will cause no problem.

Datatek · Aug 23, 2018

bstein said:
I have searched allover but I can not find an solution to my problem.
-The car is a ´99 P38. When the EAS is in "Standard", "Low" or "Access" mode the EAS is constantly adjusting up and down (1-2cm) and never settling. This causes the compressor to constantly run. When I plug in the Nanocom I can see the valves opening and closing.
When the EAS is in "High" everything is fine and the car stabilizes and the compressor switches off.

-The car will sit for a long amount off time without sinking so I do belive the system is leak free.
-All airsprings new last 12months.
-New valveblock last 12months
-New driverpack last 12months
-All height sensors new last 12months
-Switched with used EAS ECU

Any ideas or suggestions?

If the airsprings were not new, I would say you have a leaking airspring. The compressor will only run when there is a loss of pressure. I have had a new airspring that leaked, with the car at normal height, ignition off, pull the EAS relay under the passenger seat and see if it drops. Airspring leaks often open and close at different heights.
Other possibilities are corrosion on the connectors to the height sensors, bad earths on the inner wing under/adjacent to the EAS box and the driver pack. Is your new driver pack really new, or secondhand?
Another thing to try, press the lock button on the EAS control on the dash, it's next to the up/down button and see if is affects things.
There is also a connector that corrodes, memory has gone blank (age) but I think it's at the bottom of the Apost on the passenger side.

wammers · Aug 23, 2018

Datatek said:
Set within 2 bits side to side? Where did you get that from? The sensors are not that precise and the readings side to side on a flat level surface with the heights set correctly can be further out than that and will cause no problem.

It is the recommendation for setting of the front heights to avoid dancing as pressure is equalised as vehicle stops or speed falls below 1 MPH. Rear does not matter as much because no equalisation automatically takes place.

wammers · Aug 23, 2018

Check the white plug and socket applicable to EAS behind lower trim panel passenger side for corrosion. Any corrosion causing a open circuit or short circuit on this connector will give you what you have. It is the interface from height selector switch to ECU.

bstein · Aug 23, 2018

(FL,FR,RL,RF)
High: 141,141,135,135
Standard: 111,116,115,115
Low: 100,100,102,102
Access: 73,73,82,82

Driverpack was new.
Both connectors (left/right) has been cut away, wires soldered and heatwrapped.
Pressing "Inhibit switch" does not affect the problem.
Opening a door causes the adjustment to stop.

Grrrrrr · Aug 24, 2018

What are the pins like on the plug that connects the driver pack?

In the Nanocom can you take a live trace (you need an SD card in it) and then post the results?

wammers · Aug 24, 2018

Maybe if all else fails you should do as Grrrrrr suggests a check all the connections on the valve block plugs and sockets. The driver pack can cause problems if faulty but it is merely a slave of the ECU, it handles voltages to open and close valves the ECU does not use. If it is faulty as Keith says it can feedback to the ECU and cause it to get confused. But normally it just obeys commands given out by the ECU, the only feedback the ECU should get of correct driver pack operation is a change in the corner sensor readings. It could of course be a faulty height selector switch. If you look at the price of a new one you will realise it is not just a switch but is packed full of electronics which can also fail. It amazes me that they can be got for next to nothing on Ebay.

bstein · Aug 25, 2018

Please find log attached. Its just a .CSV file, but I changed the filename to .zip in order to be allowed to attach it.

I didnt log for a very long time so the compressor didnt shut off in high.

bstein · Aug 25, 2018

Here are som more logging, now while driving.

wammers · Aug 26, 2018

Your files cannot be opened at least not on my computer. Just carry out the checks as i post #9.

Datatek · Aug 26, 2018

bstein said:
Please find log attached. Its just a .CSV file, but I changed the filename to .zip in order to be allowed to attach it.

I didnt log for a very long time so the compressor didnt shut off in high.

You can't just change a file name, it doesn't alter the format of the contents. I can't open your files.

bstein · Aug 26, 2018

Just do this;
-Click the filename and download it to your computer.
-Change the filename from "T0.CSV.ZIP" to T0.CSV"
-Now open it in excel or the nanocomm csv viewer in order to view the contents.
I changed the filename just because Landyzone does not accept .CSV files to be attached.

I will check everything i mentioned in post #9, thank you for the advice.

pwood999 · Aug 26, 2018

Looks like typical height variation as the car bounces up & down while driving to me. Does it constantly adjust when the car is stationary with engine running ? If yes, then you probably have leaks somewhere.

BTW, the file is not a proper CSV. I removed the ".zip", and checked the file. It is actually a typical Nanocom "semi-colon" separated values !! Opened in text editor, and replaced all semicolons with commas so the file opens in Excel. Then it's easy to plot a graph for any set of columns.

bstein · Aug 26, 2018

It does adjust while stationery while engine running, that is the first file (log.csv). What is wierd is that when I have it in "HIGH" it does not adjust....

Wazzajnr · Aug 26, 2018

In excel, if you go to "text to columns" you can select which delimiter it uses (i.e. Semicolon) and it will separate it all for you.

pwood999 · Aug 26, 2018

Graphs are typical of slight air leak in air-bags at the lower heights. Another strange thing is Inlet & Exhaust valves are opening when the Corner valves are shut ? This suggests something leaking inside the valve block. Was it a New or Reconditioned valve block, and are the seals the red or black version?

Datatek · Aug 26, 2018

pwood999 said:
Looks like typical height variation as the car bounces up & down while driving to me. Does it constantly adjust when the car is stationary with engine running ? If yes, then you probably have leaks somewhere.

BTW, the file is not a proper CSV. I removed the ".zip", and checked the file. It is actually a typical Nanocom "semi-colon" separated values !! Opened in text editor, and replaced all semicolons with commas so the file opens in Excel. Then it's easy to plot a graph for any set of columns.

See post #4, I still say there is a leak.

bstein · Aug 26, 2018

I do not think there is a leak at the spings, but I attached some tape earlier today and we will see the result tomorrow.

Valve block was brand new. I have not opened it so I do not know the colour of the seals.

P38 EAS constantly adjusting

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