P38 EAS issues airloss/self selecting height/height hunting

Datatek said:

Are you absolutely sure that it's not the rears dropping because that can give the impression of the fronts rising and the front would adjust down before the rears rose in that situation. There is a common gallery for front and rear.
If the valve seals were leaking, and the air tank is empty you would thing that the fronts would drop. I suppose the correct springs are in place on the solenoid plungers?

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wammers said:

There are three NRVs. NRV1 holds high pressure air in the tank. NRV2 prevents air from bags flowing into tank if solenoid valves are opened if tank is empty. NRV3 prevents high pressure air from compressor flowing into solenoid gallery via exhaust valve when compressor is running. None of these can cause the fronts to rise when ignition is off. Only thing that can cause that is a leaking inlet valve solenoid allowing high pressure air to flow from tank into solenoid gallery and be forced past front solenoid valves. Front valves are used a lot more often than rear valves and are more likely to be worn.

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P38Rover said:

Yup.. it is difficult to tell what is going on sometimes while sitting in the car, so Ive been starting the car with the door open and shutting it while standing outside to observe the leveling. On a short trip she will adjust down 1-2 clicks and rears will come up at the same time with the same clicks that drop the front. Definitely unlike how she would normally, smoothly rise into each height..

All springs should be placed correctly, I took apart the valves one at a time so there is almost no chance any parts got mixed up, lost or out of order.
Personally I would just swap the whole valve block rather than pull the spare apart ad see what effect it has.



Thanks that makes a lot of sense. I have a spare valve block.. I might just pull the rear valves and swap them with my current fronts.

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Datatek said:

So in fact the back is dropping. When that happens, weight transfer causes the front to rise.
The back always rises before the front, this may happen in stages if it is coming up from access. A lot of clicks as it reaches the desired height is normal.

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P38Rover said:

I would say the rears get more compressed than anything. They dont "feel" low on air when I get in and are still near their original height when the fronts are raised high. It definitely feels and looks like the fronts adjusting down and in turn relieving the pressure on the rear. I have schrader valves installed on the bags also so I guess I can also test the PSI on them which I will try tomorrow morning probably.

Thanks for all the replies!

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Grrrrrr said:

I wouldn't leave the Schrader valves connected. The ones on my car were leaking so I removed the T's and put the pipes straight into the valve block (no more leaks) but I bought straight connectors for the Scrader valves so I can swap over to manual inflation should the need arise. Arise ... see what I did there? Never mind, I'll get my coat ...

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P38Rover said:

Update:

So in the morning the fronts were high again as expected. I threw a gauge on them and both fronts were indeed filled much more than the rears by ~20psi.

Fueled by rage, I ripped out the valve block again and swapped plunger valve seals on both fronts, inlet, and exhaust valves.

There was a very noticeable deep dimple in my original front valve seats. Which I swapped both fronts with the rears from my spare valve block. This is what came out and went in...big difference
View attachment 187749

She’s a moody bitch, so it’s too early to say she’s cured but she’s no longer raising the fronts while stationary..

We’ll see what happens..I’ll keep updating

Thanks again for all the good advice from everyone! I really appreciate it!

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wammers said:

Told ya. Listen to uncle Tony you know it makes sense.

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P38Rover said:

yes, you are quite right again dear Wammers.

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Grrrrrr said:

He usually is.

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P38Rover said:

Update:

Ive been reading way too many threads that have the exact same symptoms as mine however I haven't been able to find a thread that shows any concrete evidence for a solution. Almost all of the threads end with the owner getting exhausted of all options and giving up or just nothing; no update... This all somewhat worries me because it sounds very familiar to my experience so far. Because of this, I am determined to find a solution to this "dancing" and to finally have a thread that possibly offers a solution to others.

On that note, shes still dancing... Same as many others before me, same as Ive always known.. So now I believe that the NRV3 is leaking air causing the slow dancing..Because she will NEVER do any dancing when the tank is full and compressor is off. So what I think is happening is that the NRV3 is leaking air into the gallery and incrementally raising the suspension until the EAS ecu wants to lower it and repeat this until tank is full. But this still doesn't explain why the suspension wants to continually lower then immediately raise it in cycles....? So I haven't ruled out the drive pack yet either...

Also, the air tank is draining overnight now however I cannot find the source of the leak. She will maintain proper height even when the tank is drained. So now I believe that NRV1 is leaking while car is off and stationary. I think this also exaggerates the dancing because air leaking past the NRV1 will also leak high pressure air into the common gallery and can force its way past the airbag seals.

So Ive got some new NRVs on the way..When those come in I will swap them out, again... but this time Im putting in brand new ones at least. I will also swap around the inlet and exhaust valve seals giving both of them a fresh area of rubber to seal with. For good measure I might even swap the drive pack with a spare... But after this...other than a brand new valve block,drive pack, and ECU, I wouldve exhausted all my options...So lets see how deep this rabbit hole can go,it really cant be much further...

Im open to any ideas, that anyone has.. Please give me some new insight or some other tests to try? I will also pray to the EAS gods if that is what it takes...Or any other valve block gods that I can appease with a sacrifice of some coil springs or something? Ill try anything...

Thanks to everyone in advance!

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wammers said:

Think you had better re read my posts. I mentioned NRVs a long time ago. The driver pack if working correctly is a slave of the ECU. It carries out high voltage commands the ECU cannot handle. However the driver pack components can break down and feedback signals into the ECU causing random problems.

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P38Rover said:

Yes, you advised me many times in this thread and others that you do not believe it is the NRV's in my situation. So I went with it and tried everything else first. But symptoms remain.... and I am running out of things to replace so I figured, why not? It certainly wont make things worse.. And I dont even want to think about buying a new valve block...I think Id rather sadly just get some coils if it comes to that....

Thanks for all the help and replies again

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