EAS pump on too frequently

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Vinny73

Active Member
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154
Ok, starting a new thread on this, to keep it focussed and deal with the route cause of my recent problem.

EAS has been reset, car now back to working ride heights. It's been sat at full height overnight and no drop in height on any airbag.

BUT... when running the engine, the EAS pump comes on too often. With no apparent leaks, im wondering what this could be. I believe it was the route cause of my problem last week, which then flattened the battery with it continuing to self level over 2 days whilst off the road.

What can I check next?

What I believed it was by visually inspecting was the air pipe into the top of the air dryer, which appeared to have a 1-1.5 mm gap and was slightly raised, i've pushed it right in, it comes back up. Squirted with soapy water, no bubbles though.

Any thoughts / ideas please?
 
Could be the compressor piston seal worn..common fault. How often do you think the compressor should kick in??
Bear in mind the system is being constantly monitored.
The air springs are not like tyres..stay inflated for months...plus there are a load of valves, seals etc. working in a 10bar environment and the chance of a 100% leak free system is remote.
 
It's a curious fact, but on mine the EAS pump cuts in more often with the bonnet open. Shut the bonnet and the duty cycle drops and the overpressure release also stops??

Any idea why this might be????
 
Air presure inside bonnet is minimally higher when shut than open?

Could it also be an earthing issue? Try adding earth points (any old bits of wire to try it) between the battery and body, battery and chassis and chassis and engine. Worked on my old series when i was having obscure electrical faults ... ;)
 
Paul D said:
Air presure inside bonnet is minimally higher when shut than open?

Could it also be an earthing issue? Try adding earth points (any old bits of wire to try it) between the battery and body, battery and chassis and chassis and engine. Worked on my old series when i was having obscure electrical faults ... ;)
Click to expand...

Not a bad earth etc, the compressor relay is actually being operated more often with the bonnet open by whatever ECU is in command of relay operation. I know this because I put an LED indicator across the relay coil and the compressor is switched on and off at regular intervals regardless of the need for more pressure but only with the bonnet open.:confused::confused::confused:

I am not worried about it as it operates fine with the bonnet closed, so I assume it's perhaps something to do with maintenance checks.
 
Cheers guys. Kit looks straight forward enough.

Pump was on about every 20-30 seconds. Came home tonight, pump on once for about 2 mins, and car was still sat at full ride height anyway.
 
I'd put my money on a problem with the EAS driver pack.
If your compressor is worn it just stays on for a long time, if its switching on and off its either a pressure switch (which is v.rare despite being the most common fault code reported) or most likely a driver pack.
Does yours do a dance at traffic lights?
 
SpudH said:
I'd put my money on a problem with the EAS driver pack.
If your compressor is worn it just stays on for a long time, if its switching on and off its either a pressure switch (which is v.rare despite being the most common fault code reported) or most likely a driver pack.
Does yours do a dance at traffic lights?
Click to expand...

Mine does a little dance if I brake hard to a stop then release the brakes, is that a sign of something bad:confused::confused::confused:
 
Mine has starting dacing ever since I changed all the airbags a week ago and it did not do it before or was much less obvious.

My airbags were leaking, now they are completely leak free, I am wondering if the pressure is all at the valve block and any weakness is now showing up and thats why I am changing all the o rings and diaphragm.

I have read on dancing suspension, and it can just be leaking o rings in the valve block.

I would certainly do all the simple things that are cheap and worthwhile, even just for a service, so you can discount them before looking at electrical parts, like height sensors and the drive box.

I would have thought that electrical faults would show an EAS fault on the dash, whereas leaks dont and the system just does strange things as it gets false readings.
 
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if youre worried about the battery flatening again, drop to acess hiegt for now when you park till you get it sorted, should stop the car constantly levelling!
 
Anything that causes a volt drop or surge could theoretically affect the suspension ECU and might bring on the pump for a short time. Releasing the brake would cause a volt surge. The P38 engine bay fuse-box feeds all the others via three terminals on its base and is prone to volt drops which can cause all sorts of strange effects. I even had to split the fuse-box once and resolder the main input cable onto the printed circuit board because it had a dry joint (you could see the cracks) on the board causing volt drop. If there's anything of that sort then a surge would have more effect. Lifting the bonnet might also be causing a current draw (can't remember if there's a switch on in somewhere - there is on the classic) which could affect things. You can probably see also the air-con LED display increase in brightness when you lift your foot off the brake as well. If your EAS pump runs for anything approaching 8 mins stop and start again or the ECU will need re-setting. Poor design regarding power distribution, but I still love my P38. :)
 
Nah, mine doesn't dance. Should I put the stereo on?

Seriously tho, it's still sat, full ride height, haven't moved it. Battery still ok. All very odd.
 
I'm almost sure that the EAS pumps air into the front bags when you brake as an anti-dive measure. I can't remember where I read that to check it but I do recall it. This is why it moves about a bit at the lights but it should settle down straight away or you've got problems somewhere else.

The driver is a very hard fault to diagnose but very often people go through the whole system replacing bits before they get to it. If I was in the business of fixing these babies, and had a known good spare driver to hand, it would be one of the first things I would go for after fixing leaks. I spent a year jumping through hoops with my own, replacing two compressor seals and all the bags and o-rings in the process (persistent pressure switch fault even after replacing compressor seal, I knew that the pressure switch was fine as it worked everytime when operated manually). In the end I put in the driver pack from my classic and bingo, not a fault since.

"If your EAS pump runs for anything approaching 8 mins stop and start again or the ECU will need re-setting."
This is not strictly true rrdiver, It will only fault out a) it triggers the overheat switch (v.rare) or b) If it calculates that the pressure switch has not changed state through a worn compressor (This is where the pressure switch fault is normally reported when you have a worn compressor). For a fully depressurised system it can take over 10mins for a healthy compressor to bring the system up to normal ride height so its not normal for it to fault out that quick. Incidentally this is why, if you suspect a worn compressor, you should leave a door open while bringing a system back to life, to allow the tank to fully pressurise and switch off before it starts to fill the bags.
 
Sorry to sound like a moron - what's a driver pack? mine dances at the traffic lights, sags down at rear right corner overnight (leaking bag diagnosed and about to be replaced) and when it rises to full height, the front right corner "feels" a little low even though the height indicator stops flashing.
 
No problem rasheed, I wish I didn't know what it was either :)

Its the electrical controller that takes the signals from the ECU and operates the solenoids on the valvle block etc. Its bolted on to the valve block.
 
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