Compressor constantly running, Why??

[redandy3575]

Hi all

I did the valve block overhaul yesterday and now like before have found the compressor (overhauled also) is running pretty much constantly. It does shut off, but after about 15 seconds it restarts again then runs for about another minute then shuts off again for 15 seconds. Has anyone else had this issue?

I'm guessing it may be the pressure switch, but then again if it was, then it wouldn't be switching off, i'm puzzled to what it can be.

i did the soapy water test around the hose collets with no air escaping.

[Hoges]

You have a persistent leak somewhere.

did you squirt soapy water over the valve block exhaust outlet to see if it's an internal leak?

It's also possible you have an airbag leak... try squirting the soapy water around the inlet on each airbag and see if there's a leak there... have you checked for cracks etc in the bags?

Raise the vehicle to Max, wait for the compressor to stop and see how long it takes to restart, try the same at the Access height. If the compressor behaviour is significantly different (= improved) at these heights vs. Standard height it could be a split that is self sealing...

Reason: A hairline split may develop in the bellows at normal height because it sits at that level the most and hence the bellows deforms and gets stretched continuously at the point where it turns over on itself. It may however self-seal when either at Max or Access heights because that section of the bellows is no longer deformed and is in fact "compressed" compared to what it was before....:eek:

If there's no change it could still be a bellows problem...just a different one! ...more soapy water and lots of silence to listen for the dreaded "hiss"!!

Good luck

[redandy3575]

You have a persistent leak somewhere.

did you squirt soapy water over the valve block exhaust outlet to see if it's an internal leak?

It's also possible you have an airbag leak... try squirting the soapy water around the inlet on each airbag and see if there's a leak there... have you checked for cracks etc in the bags?

Raise the vehicle to Max, wait for the compressor to stop and see how long it takes to restart, try the same at the Access height. If the compressor behaviour is significantly different (= improved) at these heights vs. Standard height it could be a split that is self sealing...

Reason: A hairline split may develop in the bellows at normal height because it sits at that level the most and hence the bellows deforms and gets stretched continuously at the point where it turns over on itself. It may however self-seal when either at Max or Access heights because that section of the bellows is no longer deformed and is in fact "compressed" compared to what it was before....:eek:

If there's no change it could still be a bellows problem...just a different one! ...more soapy water and lots of silence to listen for the dreaded "hiss"!!

Good luck

Checked it out, there doesn't seem to be a hiss. I'm guessing the thin air line might be to blame. Just tested it again and this time it stopped and didn't switch back on till i started to raise and lower the vehicle. Don't know, will keep an eye out.

[redandy3575]

Yeah don't know......... I drove all the way up to Cape York and back without any issues or faults with the EAS, however the compressor is still behaving strangely. I'm wondering weather the compressor after switching on and off about five times then stops for a while is a result of the compressor overheating with the thermal switch intervening. I'm still yet to test for leaks at all levels as Hoges suggested (might do that tomorrow), but am not convinced that that could be the problem. I did notice also a slight re-adjustment of the springs when driving on Normal ride height, it has got me slightly stumped!!:(. I'm also wondering if that is the Normal erratic behaviour of the EAS.

[RR P38]

When you overhauled the piston and barrel it might not have gone well.
Possibly you are only just making the pressure cut off switch set point, just.
And with a small leak pressure drops then the cycle starts again its like a bouncing ball.
Its handy to know how much pressure you have in the receiver.
I have put a shrader valve in my receiver drain plug, this allows me to put air in and take air out of my receiver and check the pressure in there.

If you leave the RR over night with the relay out of the EAS ECU does one side drop more than any of the other 3?

[redandy3575]

When you overhauled the piston and barrel it might not have gone well.
Possibly you are only just making the pressure cut off switch set point, just.
And with a small leak pressure drops then the cycle starts again its like a bouncing ball.
Its handy to know how much pressure you have in the receiver.
I have put a shrader valve in my receiver drain plug, this allows me to put air in and take air out of my receiver and check the pressure in there.

If you leave the RR over night with the relay out of the EAS ECU does one side drop more than any of the other 3?

Possibly, will have to check it out. Do you think maybe the valve block itself maybe leaking?

The pressure does remain in the air tank as when I start the car in the morning, it pumps straight up without delay, but think maybe one of the solenoid maybe leaking.

[DT-P38]

Take off the cover and spray test the valve block around the solenoid bases (without drowning anything) of the top ones. You will probably find bubbling if you have inadvertantly crushed some of the really small inner (flat, thin) rings. If so, undo it and test the botom ones as well.

I was silly enough to give them a twirl when I did mine (thinking I would seat them better) and wrecked the majority of them.

Also, your compressor might need a kit through it if that hasn't been done before.

[redandy3575]

Could it possibly be the small o-ring in the compressor head?

[superquag]

You mean the one that seals against the reed valve? -

Quite likely. Mine was sort of melted, due to not sealing 101%, therefore the compressor took longer to build up pressure, which meant it got hotter, which softened the rubber even more and some stuck to the reed which meant it sealed less, so the pump had to run longer....

A tiny leak will result in total pump failure, eventually.

[redandy3575]

You mean the one that seals against the reed valve? -

Quite likely. Mine was sort of melted, due to not sealing 101%, therefore the compressor took longer to build up pressure, which meant it got hotter, which softened the rubber even more and some stuck to the reed which meant it sealed less, so the pump had to run longer....

A tiny leak will result in total pump failure, eventually.

Yeah that's the one. I opened up the compressor again today to see if that was the case, i readjusted the tension clip to make it press up against the seal a bit harder as air was slightly leaking out as i blew air in through the outlet connection, it now seals a lot better. I found another leak between the pump and the block which i sealed up using plumbing tape, so all good there.

However after observing the compressors operation starting from the High setting it ran for about a minute to top up the tank, then shut down for about 10 seconds, restarted ran for 30 seconds then stopped again for 10 seconds, then restarted and ran for about a minute again, then stopped and stayed off.
I then dropped to standard height, and the compressor stayed off (as it should seeing that your not using any air). Dropped to Highway height, same thing, as was with access mode. Going up again rapidly to Highway the compressor fired up again doing the same cycle as before, shutting down and restarting 3 times before again staying off till raising up again to standard and High mode.

I'm starting to think that this operation is Norm after reading on Rangerovers.net the column regarding 'Faulty Air Suspension operation that might seem Faulty' where it describes the pressure switch failling to recognise the correct pressure, and as the compressor shuts down that there is an immediate drop in pressure for the switch to restart the compressor again till the pressure was high enough to stop the switch from restating again, :angel: i don't know!!! I'm probably trying to avoid having to take out the valve block again to check the seals.
The thing is, the springs don't deflate overnight and even after a couple of days still remains relatively inflated (unless your parked on uneven ground), so i cannot see or hear any leaks post-valve block, even after spraying gallons of leak detection water over everything including the valve block.

Right, so here is what i want everyone to do, is to go outside, and see if your air suspension is doing the same thing as mine is by adjust to the different ride heights and observing the compressors behaviour:p:D

[redandy3575]

UPDATE: Ok, i took out the valve block again!!! to have another look. Checked all the seals, all good. There doesn't seem to be any leaks anywhere, the valve block is operating as per normal, no air is leaking out and in the morning the air springs are still up (not sagging).

I'm starting to lean more towards the compressor not providing enough pressure. I did a seal replacement about 3 months ago, and i think i may have damaged the piston itself with a couple of burrs from the flat screwdriver, which i did sand smooth again, but may be enough to prevent the compressor from reaching the right pressure.

[wayneg]

It is easy to put a burr on the piston when replacing the seal. Even if the seal is new the burr will quickly carve a nice groove into the cylinder. Bite the bullet, buy a new cylinder, pull the compressor apart and get rid of the slightest burrs on the piston and seal retaining ring.
Even with a perfect seal the compressors slow down with age, I have 3 and they all are good but pump at greatly differing rates, one is pretty useless. The next time one packs up I shall be fitting a Viair type pump beloved by the American air riders. No doubt you would have to do a few mods to get it to fit
There are some great deals on generic ones at the moment on e-bay
http://www.ebay.com.au/itm/New-Chrome-220psi-AIR-COMPRESSOR-Air-Ride-Airbag-Suspension-System-Kit-658-/200773242389?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ebf048e15

[glenhendry]

I think you need to be monitoring the pressure in the tank to know when the pump should be on and off? A gauge off the main storage tank has to be the definitive way to know if there are leaks in the system causing the pump to run?

[redandy3575]

Ok, i've installed a fully refurbished compressor which seemed to pump up the system quicker, but still misbehaving slightly though not as bad as before.

I've got to get myself a pressure gauge and see if air is possibly leaking between the valve block and the air tank. The problem is that the air line runs in hard to reach areas above the chassis. Though i'm still not convinced that there is a leak along that line, as after leaving the RR for 3 days, and came back, pulled out the air line from the the tank, and there was still a humongous amount of pressure there, so it cannot possibly be that, or can it? Can the pressure switch be the cause?

[RR P38]

Are you hearing the EAS compressor running?
Try replacing the mounts on the compressor.
These things do run a lot, the system is not really all that intelligent and is constantly adjusting its self.
Have you recalibrated the height sensors via test book/Hawkey etc?

[redandy3575]

Are you hearing the EAS compressor running?
Try replacing the mounts on the compressor.
These things do run a lot, the system is not really all that intelligent and is constantly adjusting its self.
Have you recalibrated the height sensors via test book/Hawkey etc?

No, i can't say that i have

I did replace the rear left hand sensor recently with a newish type. The sensor came with and adjustment bracket which is suppose to re-align the sensor to its true position. After i installed the sensor, the EAS went back to normal, and the fault was cleared with the kicker, and the sensor numbers matched with the other sensors, so i'm not sure if there is anything else that needs to be done.

Maybe i'm just getting paranoid!!!![tonguewink][bigwhistle]:wacko: