EAS troubleshooting driver pack

[AJV]

Hi all,

I've got a an issue with the EAS - it wont level from wade height, and is currently back high, front low and can't shift the heights.

*****Background *****

Short story I've bought a new (2nd hand) valve block and driver pack. This was to replace an existing valve block that had what looked to be desiccant and residues blown through it - coupled with a average job I did burying a sheared bolt in the block - I decided to get a nice new (old) block.

TI also previously had an issue where the front driver side air spring would constantly try and find level, and was overworking the pump. Some conversations with rangie mechanics plus thorough leak check job, the suggestion was it may be the driver pack.

As I needed a new block anyway - a driver pack came with it, so figured was an easy install. Redid the o-rings in the new valve block - and had to swap out the pressure sensor as the old one had been cut for some reason. This too was no worries.

I also redid the air dryer at the same time.

It all went back in no worries. Leak checked and seemed to be good.

****Current issue****

On start up the system began pressurising, I could feel the love...until it kept pressurising all the way to wade height (of which I did not select). Switching heights resulted in no change, except on several occasions dropping it to access dropped the front two springs to access (but not the back two). So now I have a p38 front low, back high (I call this the backwards hyena setting, because humour is all I have right now)

***Things I've checked***

Checked it via RSW checker - no hard faults. And to further the issue - as am prepping to take the valve block out to recheck fittings and connections I can't get the EAS to take the air spring depressure commands (I assume it is accepting the depressure tank command...maybe - can't know don't have an inline gauge installed). Strongly prefer to depressure via RSW before pulling the air lines. Can confirm RSW is talking to the EAS ok - as can send pump run commands, clear soft (car moved) faults etc.

Checked plug connections, vehicle to EAS. Contact sprayed again (confirm all connectors were cleaned before reinstall new block and driver pack)

Have not checked not driver pack to solenoid plug (next after get block out of truck)

Leak checked everything except rears.

**Thoughts**

I am hoping this is mechanical. Thought it might be stuck diaphragm I wasn't careful with silicon grease hands when reinstalling the new diaphragm - but note car has achieved pressure release(s), being down on the front two after testing dropping it to access (and it did just not the rears).

Potentially something of issue with the pressure switch? Although compressor seems to be cutting in and out appropriately suggesting its achieving the correct psi for cut in/cut off.

Only other matter I thought was I might be unlikely enough to have a duff driver pack (if the original was actually duff).

Another EAS riddle from a P38 amateur har har. But really appreciate any tips or thoughts! I've done my standard gtsooi (google the sh...out of it)

I'm benefitted by having spare solenoids, covers and pieces from the old block to test components.


Look forward to any thoughts! [biggrin] or questions! My P38 looks like its on crutches right now.

[prelude]

What comes to mind (I am currently way down bush in sweden and my pressure drops to 2 bar every night so every morning the system has to work hard to get back up again):

If the system can pressurize and depressurize that means the valves work correctly. If you look up a diagram on how the EAS air flow works you will find that there is ingress an egress of air through a single path (through the dryer). If the fronts can lower, the pathway for letting air out works so it should work for the rear as well. The rear valves work, else they can not inflate. The exhaust valve works, else the fronts can not deflate. So we have ourselves a little mystery here. It COULD be the driver pack, though all the functions individually work as I already explained. Perhaps the combination of exhaust port and rear valves can't operate together, I don't know. I have never taken the time to figure out the driver pack but it is on my ever growing todo list since it seems to be a vulnerable part and should be quite easy to build a replacement for with some FET's or whatever.

So, yes, the driver pack is my first suspect since I can not figure out a way how you would get this error mechanically. This is of course assuming that the rears go up to wade height actually and not just blow up to the max due to the valves being open all the time? (this would deflate them simultaneously with the fronts though so I guess not?).

Well, back to finding my own gremlins...

Cheers,
-P

[AJV]

What comes to mind (I am currently way down bush in sweden and my pressure drops to 2 bar every night so every morning the system has to work hard to get back up again):

If the system can pressurize and depressurize that means the valves work correctly. If you look up a diagram on how the EAS air flow works you will find that there is ingress an egress of air through a single path (through the dryer). If the fronts can lower, the pathway for letting air out works so it should work for the rear as well. The rear valves work, else they can not inflate. The exhaust valve works, else the fronts can not deflate. So we have ourselves a little mystery here. It COULD be the driver pack, though all the functions individually work as I already explained. Perhaps the combination of exhaust port and rear valves can't operate together, I don't know. I have never taken the time to figure out the driver pack but it is on my ever growing todo list since it seems to be a vulnerable part and should be quite easy to build a replacement for with some FET's or whatever.

So, yes, the driver pack is my first suspect since I can not figure out a way how you would get this error mechanically. This is of course assuming that the rears go up to wade height actually and not just blow up to the max due to the valves being open all the time? (this would deflate them simultaneously with the fronts though so I guess not?).

Well, back to finding my own gremlins...

Cheers,
-P

Thanks heaps for the thinking. I might isolate the driver pack by reinstalling the old one back in (after tested contacts b/w solenoids and driver pack). Hopefully that leaves something mechanical.

I do notice it seems the rear passenger side is maxxed. This doesnt look like wade height, but max inflation. This is not the same on driver side rear - but it is parked uneven passenger side onstreet slope down...

[prelude]

no problem :)

Although a slope will cause a slight uneven weight distribution and thus a higher pressure in one of the bags, the height should remain the same (that is what the height sensors are for). If your gadget to read/reset the ECU supports it, you can read the height values of all sensors that should give you some insight. A tape measure should also do :)

Cheers,
-P

[AJV]

no problem :)

Although a slope will cause a slight uneven weight distribution and thus a higher pressure in one of the bags, the height should remain the same (that is what the height sensors are for). If your gadget to read/reset the ECU supports it, you can read the height values of all sensors that should give you some insight. A tape measure should also do :)

Cheers,
-P

Can confirm that all real (mm) heights across the vehicle are different. This is reflected too in the bit readings from the height sensors which I can read from the tool. The passenger side rear is very high, maxxed I would say (looks like a dog taking a pi$$).

Safest way to depressurise when the EAS is not responsing to depressure commands is a question I have now

[prelude]

That is a tricky one. You can just disconnect the tubes. it's not that hard to do but it might give a bit of a scare as the air escapes. It won't blow your skin of your hands or anything :) but it certainly can be a bit tricky. The alternative would be to open the valves by directly feeding them power, however, as i understand it (but have never confirmed myself by measuring) the valves are opened with a PWM signal since a continuous current could/would damage the coil.

Mind you, you would have to disconnect them all and power them directly and individually to do so. You would need to operate two: the outlet valve and the valve of the spring you wish to deflate (or the tank valve to empty the tank).

Good luck!

Cheers,
-P

[AJV]

Update to close this one out!

Replaced driver pack with original - new valve block seals etc.

All fixed! no dancing on the driver side anymore. Levels look good, height sensors achieving written bit heights and no undue compressor running now.

Potentially the new (old) driver pack I got with the new (old) valve block was duff. Or could've been a dodgy connection.

I do have what looks to be a leak on that side (after isolating self level by removing EAS/ECU relay). Have some new springs coming so will redo. Confidence it is a leak in the spring as I've done the valve block twice and this settling has been an ongoing issue on that side.

thanks heaps @prelude for keeping me company through this

[prelude]

That's good news! It's always nice when the car works as it should :) And glad to help!

Cheers,
-P