EAS behaving erratically- please help

[UK_P38]

Just when I thought I had it all sorted!

Today I checked my valve block again as I was still getting some drop over night and found that 2 of the solenoids had very slight leaks. I took them off one at a time whilst still fitted to the car, re-seated all the o-rings and put them back on. All seemed fine, no leaks, on first start up the car lifted and levelled, then fully pressurised the tank, didn't notice anything out of the ordinary. I shut it off and left it for a few hours, didn't appear to be leaking.

Now the car is doing very strange things. It takes ages to go up to any heights and at motorway, normal and off road the rear left suspension just goes up and down constantly! I haven't changed anything, the only things I did differently this time were (as I didn't have my laptop with me):
Unplugged the EAS unit by pulling out the 'black box'
Deflated the bags manually through valves
Pulled the line from the tank to valve block to deflate tank
Didn't have any faults but plugged an automatic 'kicker' in from another car

What can cause this? It is like the rear left is going from low to high, searching for it's position! I think the fact the air is going in and out of the rear left is why the tank can't get to pressure, hence the slow change of heights.
Trawled the internet but not found anything yet!

[UK_P38]

Oh and I plugged in my RSW software when I got hme, no faults and no faults flashed up at any point in the day....

[Rupert Prior]

sounds like you have internal leaks. inside the valve block (high pressure air is getting to places it should not, wrong valve in right hole or leaking valve galleries). there is a small possibility that you have the two rear bag hoses swapped, but this normally makes the car lean to one side unless the compressor cannot put out enough pressure. in which case one side goes up and down slowly.

[DT-P38]

This all occurred at my place this afternoon. I have never seen a P38 behave like this.

It was automatically lowering itself from any manually selected height (inhibit switch on) and then raising itself again virtually straight away. It seemed to only drop one level from what ever was selected but every now and then drop two levels. The raising process (rear first each time) was generally slow as if no pressure in the tank. The same behavior happened with the inhibit switch off. But then it seemed to move up and down over all levels more randomly.



there is a small possibility that you have the two rear bag hoses swapped

Some pipes the wrong way round was one of the possibilities I thought of while watching it "dancing" too. It just looked confused?!? If that makes any sense...

If one of the small inner solenoid O rings dropped off (with out being noticed) when putting it back in would that create "high pressure air going where it's not meant to"?

Would a knackered height sensor force the hunting effect of it dancing up and down? At what point would that hunting/dancing create a fault?

I also thought the EAS driver could be shot just simply because something kept forcing the thing to lower off a selected and inhibited height. Any more ideas?

UK-P38, I am gonna get my spare valve block back tomorrow and rebuild it so we can swap it over and open yours up. Will give you a call tomorrow.

[Hoges]

Couple of things: Have good look at the EAS Driver block mounted on the Valve block beside the compressor. It is resin sealed. If the resin is highly discoloured and flakey it's a reasonable bet that the Driver is shot from heat shock and needs replacing. It will play all sorts of tricks when it's not working as it should.
Have a look at the height sensors with an analogue multimeter. As the sensor is opened and closed smoothly, the change in resistance reading should likewise cause the needle to swing evenly. If it jerks around, then there's a problem with the tracks. Inside the circular "elbow" of the sensor, there are three 'fingers' which press on three parallel copper tracks thereby making contact. The tracks become worn.

If there is a problem with the tracks, swap the sensors L<->R (if this has not been done previously) and they will behave essentially like new. The sensors are not "handed" so can be fitted to either side of the vehicle. Let's say there's about 270 deg of movement in total, but only about 60 deg is used between access/high settings. Thus when "inverted" to fit the other side of the vehicle the hitherto unused section of track is pressed into service.

Assuming all valves are operating as they should, the front end 'dancing' points to a faulty sensor and/or a dodgy EAS Driver block...it could be both.
Let's know what happens?
cheers

[UK_P38]

Cheers guys, after some more searching it does sound like it could be either the drive block or height sensor. Possibly lowering the car this time was the one to push the sensor over... The thing I find strange is that it just started happening after only really minor work to the valve block. Didn't even remove it and didn't touch the solenoids on the underside, so cannot see how air can all of sudden be leaking to the rear left...

Will try swapping the rear sensors over. Going to look at the software readings as the rear left goes up and down at lunchtime...

DT-P38, does your other block have the driver too? Will be pretty simple to plug another one in?

Maybe it's just wants to Rock around the Christmas Tree!

[DT-P38]

DT-P38, does your other block have the driver too? Will be pretty simple to plug another one in?



No but I know where we can source one relatively easily.

[UK_P38]

I just checked the height sensor height readouts on the RSW software as the car danced around and they seemed to correspond with the wheel positions suggesting the sensors are fine. I think I will swap them to be sure when i get the chance. During testing it started searching with less extremes in height but at other times it went back to the original big movements. I did try playing with the wires coming out of the 'black box' that gets pulled out to shut off the EAS controller but could not find a correlation between doing this and the 'searching' getting better or worse (it never actually stopped searching and was settled). Could damage to these connections cause the problem, maybe the wires were yanked when the box was removed, I'll remove the plastic covers to get a better look...

It seems to be doing the following cycle, maybe...
Pump up tank to 140psi, let up rear left higher than it should be, refill tank to 140psi and let the rear down beyond level, then repeat. The amount of up/down seems to vary.

Thoughts now go to the driver, obviously, with all the pumping, it gets pretty hot in there. I guess the only test is swap it out?
When the engine is shut down it seems to go through a lot of levelling process also, probably related...

Certainly getting familiar with the system! Anyone else had anything similar?

[mtb_gary]

UK_P38

I'm guessing here that you have an EAS bypass with a guage for measuring the tank pressure? Hence, you know that you are getting up to 140 psi in the reservoir. Working on this assumption can you remove the "black box" relay from under the passenger seat to disable the EAS system then manually inflate the left rear with a compresser. Once this is done does the bag deflate immediately? If yes I would look at potentially a valve stuck wide open, if no then I would start looking more at electrical parts such as the sensor or EAS driver block.

Good luck

Gary

[Keithy P38]

Good suggestion mate!

[UK_P38]

As always a great response and much appreciate all the support!

I did some diagnosis this evening (a lot of observations and playing with valves) and have come up with a potential theory using all your info.
Firstly to describe my EAS bypass kit: It's the Faskit one, it has 5 bypass valves, 4 sit in between the bags and valve block. When 'open' the path is normal between the valve block and the bag. When 'closed' the valve block line is shut off and the bag is connected directly to a schrader valve so it can be pumped independently. The 5th sits in the outlet of the pump, with a pressure gauge, this reads the outlet of the pump, so as it pumps up a bag you can see what it gets too, then you can see the pump rising to 140psi before the pump shuts off and the gauge registers 0 (bit pointless as it measures between the outlet and valve block). This also has a bypass and a schreder valve that enables the compressor to be used independently, connecting to each of the bags... Hope this makes sense? I think I will connect the 5th to the tank instead...

My theory: The rear left is being pumped up when the pump is trying to fill the tank, via an internal leak or a jammed open valve. Also my kit must have a leak on the rear left bypass valve as with it closed it continues to adjust this wheel height, the others can be shut off with the bypass ( I will be speaking to the supplier). I checked my plumbing of the kit, blowing through the tubes, all good. The system gets confused, it is trying to get the tank up to pressure, once full it realises the rear left is high, so it releases pressure to get it down, then has to refill the tank, but finds pressure is dropped as it's linked to the rear left... Possibly, at the weekend when I released the tank pressure (I usually use the RSW software that does it in a slow controlled way) I just pulled the tank line to the valve block, maybe this has blown one of the internal seals. I believe the rear left is the 1st to see airpressure in the system from the inlet. Or the rear left valve is stuck open, strange that I never touched it. When it adjusts the rear left back down, the tank pressure drops too. The block will be coming out again tomorrow and I'll report back. Anyone else think this makes sense?

Really appreciate all the suggestions and help, great community on here!

[DT-P38]

That all makes sense to me. You are getting close I reckon.

Only one thing for it... Pull block and open it up again. Use Paul's instructions they are GOLD. The photos can help identify if something is in the wrong spot.

I still think it could be that it just doesn't like you. Probably something to do with sticking that headrest in the wrong way!!! Bring it back to my place when you've had enough of it my "pretty pig" could do with a mate.

[PeterAllen]

In the event you do have a stuck valve make sure you inspect the rubber bits on the top and bottom of the stem (not just the "o" rings). The top should be flush with the top of the stem and the base rubber should be flattish and without indentations. If the top rubber is misaligned, myself and others have carefully superglued them back in place. The bottom rubber can be sanded back with emery paper or around 2000 grade wet and dry. Using a drill press for this would be ideal but can be done by hand with similar effect.
Personally, with a stuck valve, I have always been thrown a hard fault when it occured, so I am leaning towards another cause.

[UK_P38]

Progress so far, or lack of..

Took out the valve block and took off the bottom two valves (front right and back left). Nothing obviously wrong, carefully re-seated all the o-rings just in case. Removed the two removable blocks, one connects the inlet of the compressor/ diaphragm valve and the exhaust to the main block, the other sits at the other end with the pressure switch, all the o rings looked absolutely fine. I did not touch any of these to cause the problem so that is logical.

Reconnected it all back up, exactly the same behavior.

I then switched the the two rear height sensors over, problem persisted.

Something else I have noticed, it only seems to do it while in park. When I'm driving a long or at lights in gear, all appears fine. Left it is gear and had a look, seemed fine.

It leading towards me thinking it must be a control issue, leaving the rear left valve open when the tank fills.

Sooo, onto the next. After some thinking on my way home (I did this in my work carpark), I'm next going to the 'black box' that you pull out to disable the EAS ECU. When the problem started was after the 1st time it had been pulled out, so makes sense. I'll remove the covers and see if the wires look disrupted. Then it will be the driver, DT-P38, how easy is this spare one to get hold of? Would be extremely useful :D

Certainly getting to know the system pretty well and getting pretty swift at pulling it apart!

Not one error message has been generated during all of this.

Suggestions always welcome ;)
Will report back with findings

[UK_P38]

Had a quick look at the wiring under the seat and inspected the 'Black box' that I now know to be the timing relay. All looked OK, cover did come off the timing relay rather easily to reveal the circuit board but all the solders were in tact with no cross overs. Surely the timing relay cannot have much effect?

Have read that a blocked exhaust silencer can do strange things, will try without it after work, noticed mine was very hard to blow through yesterday and soaking in water wouldn't unblock it..

Possibly the driver pack then, anyone got one in the Melbourne area I could try in return for cold beer please?:p

[FANTOM P38]

Hi UK_P38,
Correct me if i'm wrong but from my understanding you did not have this issue prior to dissasembly of valve block ???
So if that is true then it would not make sense for it to be a sensor or driver box.
It sounds to me more likely something to do with solenoid that may have been dissasembled and possibly sticking open. Did you only lube correct orings! as some should not be lubed at all. This is where Paul (Hard Range) instructions are invaluable in rebuild procedure. Worth another look I think.
Hope you get it sorted soon, need to get trip happening, starting to get withdrawal symptoms!
Cheers, Martin

[DT-P38]

Don't have an EAS driver handy now. Anyone have ideas about where one may be waiting for use?

[FANTOM P38]

Only thing that seems a bit strange though, is that no faults or messages popping up!

[Rupert Prior]

in one reply you mention the bottom 2 valves as being FR, RL. i think that is wrong. i seem to remember they were FL, RR. i still think you may have the hoses in the wrong holes.

[DT-P38]

Does anyone know Is there an EAS fault finding guide/check list like the one on RR.net for HEVAC?

[PeterAllen]

I haven't found any exhaustive checklist to determine the faults. As an aside, have you checked the pressure switch? I recall once my pressure switch was causing unusual issues with the EAS. I am pretty sure there is a simple multimeter test on storey wilson site. May as well rule it out of the equation as a suspect.

[UK_P38]

Thanks Rupert, it was not that I had my lines mixed up but I was looking at the wrong valve! :bangin:
Checked the actual rear left valve and found I had pinched the inner bottom o-ring during refitment. Cant wait for the time when someone says to me 'RIGHT hand down or you'll fall over that cliff'!

This has resolved my rock n rolling :D and been a great opportunity to familiarise myself with the system!

I still have the issue of the car levelling when parked up, when I get out I see/hear the car lowering itself through the valve block.. .Can i swap the front height sensors in the same way the rears do?

[Hoges]

Re. swapping sensors...As Big Arnie would say "You can dooo it"!:D

[jotape]

If you swap the sensors i think that you need to recalibrate the suspension. That might explain why your car is levelling in park.

[PaulP38a]

Haven't been here for a while due to lots of travelling for my day job... thanks for the reps guys :D

It is not a bad idea to print a copy of this schematic and keep it in the glove box as a handy reference http://hardrange.com/downloads/manual/EAS-ValveBlock-v1.5.pdf

Reading through the thread, my money would have been on the Driver Unit.

Other than swapping the solenoid caps (an easy mistake if you do not number them), make sure that you put the correct solenoid plunger "feet" in the corresponding solenoid shaft. See the schematic referenced above for which of the three types of plunger "feet" go where.

Cheers, Paul.

[UK_P38]

Swapped front sensors over, still self levelling far too much when parked up... Away for Christmas but will continue to find the cars 'personality' issue on my return!

[jotape]

Swapped front sensors over, still self levelling far too much when parked up... Away for Christmas but will continue to find the cars 'personality' issue on my return!

Recalibrate.