EAS: sensor question

My car has started doing what it did again. It will hold its height all night on all corners but drop (a bit) whilst driving. As long as I let it raise when parking before turning the engine off, it'll be ok. But it I pull in to the drive and turn off straight away, you can see its lowered to access. Upon starting the car, it will shoot back up to normal in, maybe, 2 seconds. So it's quick enough.

Now this morning, when I came to start it, the car was in access mode again and the lights were flashing away, but it just wouldn't raise. I mean nothing. Not even a tiny bit of movement. Turned it off and on again. Still nothing. Left it sat running for a while. Nothing. Still flashing to show it was trying to rise, but no movement and also no errors.

I thought "I'll worry about it later" and drove down to sort the horses out. I'd only done a few hundred yards before it suddenly popped up to normal like there was nothing wrong.

All seals have been done. All bags done. All seals and lines checked for leaks as far as I can.

The only thing not done are the sensors and drive pack. I don't even know what the drive pack is but would a dodgy or dirty sensor cause that sort of behaviour if its bouncing around whilst being driven? If one sensor was knackered, wouldn't the other 3 corners rise? Or at the very least the whole front or back? I thought maybe a door switch but there were no lights on or warnings on the dash and no errors logged on Nanocom. (I do occasionally get "unknown fault" on the Nanocom but it doesn't cause EAS to shut down or anything)

Any other ideas?

tnx

Nik

The driver pack is the black box fitted to the side of the valve block. It takes low voltage signals from the ECU and switches an high voltage to open and close the solenoids. It lifts the solenoids then drops them in a controlled manner to prevent undue seal wear. That is all it does. The sequence of valve opening is controlled by the ECU the driver pack is just a slave of the ECU. Rear end should always lift first then front. ECU instructs driver pack to open or close solenoids as required according to signals received from height sensors. Car not rising and no faults shown is usually a lack of air pressure. The longer it takes to rise the weaker the compressor. Not rising straight away in the morning, then rising after you drive for a while is classic of a pressure side leak. Usually NRV1 or the connections to the violet pipe, valve block to air tank. Or the line itself. If the car drops to the bump stops on start up in the morning you have a storage leak and NRV2 is duff. Allowing air to flow from the airbags into the empty air tank. If you have read my "How to" you will note comments made about red O'rings. They are to soft, IF there is any sort of wear on the NRVs they distort and leak over time. Will only be cured if it can be by fitting harder black Nitrile O'rings.

Thanks Wammers. I am getting the hang of it honest!

I've taken the NRV block off, cleaned it with brake cleaner until it's spotless, cleaned and dried the valves and o-rings and put it all back together again. I did the o-rings in there a couple of weeks ago and used black ones all round.

I'll see how it goes after a dismantle, clean and rebuild.

Nik

Still playing up. But it is definitely losing height whilst driving. As soon as I park and remove my foot from the brake, it jumps up to normal height - it says normal on the dashboard throughout, but it still jumps up whilst stationary.

I'm going to take the self-level relay out again on friday night and try and leave it all weekend to see if a corner drops, but I've had it up to wading height and left it overnight before and its been still there in the morning.

I don't feel anything coming out of the exhaust and I've never quick enough to catch it self-leveling and try it then

Nik

You can try to calibrate and see if it helps. I bought some 30mm dia nylon round bar rod from ebay and used this guy method:

Air Suspension

No more weird self-leveling and no more going to offroad height while driving.

JotaPê;2564130 said:

You can try to calibrate and see if it helps. I bought some 30mm dia nylon round bar rod from ebay and used this guy method:

Air Suspension

No more weird self-leveling and no more going to offroad height while driving.

Click to expand...

Block dimension information is already contained in my "How To" at top of page.

recheck the big black seal in the compressor mine did the same it had distorted

wammers said:

Block dimension information is already contained in my "How To" at top of page.

Click to expand...

I read somewhere that you can swap the sensors around left to right so that the car is then using the "clean" bit of the sensor as it would be reversed.

I know I'd have to re-calibrate, but worth doing or more trouble than its worth?

Nik

mutsnutz said:

recheck the big black seal in the compressor mine did the same it had distorted

Click to expand...

I'll check. I've re-done exhaust NRV seals, so may as well check the compressor again

Nik

NikTheGeek said:

I read somewhere that you can swap the sensors around left to right so that the car is then using the "clean" bit of the sensor as it would be reversed.

I know I'd have to re-calibrate, but worth doing or more trouble than its worth?

Nik

Click to expand...

Can be done. Never done it myself but a few others have.

wammers said:

Can be done. Never done it myself but a few others have.

Click to expand...

Don't bother is the answer. The plastic is too brittle with age and breaks as you undo the bolts securing them. Much better to buy a new set than try and swap old ones around. I ended up epoxying one back together again!

Anyway... calibrated my system using blocks and all that proved was that the method using the centre of the wheel to centre of the wheel arch is damn accurate!

But the car is still dropping whilst been driven.

1. All bags done (and checked for leaks
2. All seals done
3. Exhaust diaphragm done a second time
4. Valve seals done a second time
5. Compressor done (once)
6. Checked for leaks with soapy water
7. Pulled out self-levelling relay and it doesn't drop. But does with it in.

Anything else to try?

Nik

Lack of air pressure or a leak somewhere.

You either have a leak or a duff sensor/sensors which are you going for.

I've ordered a new set of seals from SymliesP38 as the previous set came from someone else. If that works, I'll re-post and let you know and then name/shame the ones that didn't work. I already had a dodgy diaphragm of them....

Nik