EAS pressure won't rise over 105 psi

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NicP38

NicP38

Member
Posts
96
Location
Switzerland
[FONT=&quot]Hi all,[/FONT]
[FONT=&quot]I’m still struggling with my eas compressor running almost continuously (but not burned out yet) as already mentioned in a previous thread.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]I’ve tested the line going into the tank with a pressure gauge. The result is: the pressure never goes over 105 psi. Accordingly to RAVE the pump switches on at 7.3 bar (roughly 105 psi) and stops at 9.5 -10 bar.
[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]So that’s the reason why the compressor is always running. It runs and then there is a puff noise, air comes out from the exhaust filter and the compressor starts again.[/FONT]
[FONT=&quot]Leaving the car at night I lose about 1-2 psi in 8 hours which I think is quite normal. The car doesn’t drop.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]As Saint has suggested in my previous thread it could be NRV1 and I’m quite confident it is.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]But wouldn’t I lose more than 1-2 psi in 8 hours if NRV1 were leaking? I’m quite confused.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Could it be that something in the block (NRV, solenoid or diaphragm) start leaking only above 105 psi? Like it can’t maintain any higher pressure?[/FONT]
[FONT=&quot]I’ve ordered new o-rings and will strip the block once again. But I would like to have your opinion on this strange behavior.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Thank you for reading.[/FONT]
 
NicP38 said:
[FONT=&quot]Hi all,[/FONT]
[FONT=&quot]I’m still struggling with my eas compressor running almost continuously (but not burned out yet) as already mentioned in a previous thread.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]I’ve tested the line going into the tank with a pressure gauge. The result is: the pressure never goes over 105 psi. Accordingly to RAVE the pump switches on at 7.3 bar (roughly 105 psi) and stops at 9.5 -10 bar.
[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]So that’s the reason why the compressor is always running. It runs and then there is a puff noise, air comes out from the exhaust filter and the compressor starts again.[/FONT]
[FONT=&quot]Leaving the car at night I lose about 1-2 psi in 8 hours which I think is quite normal. The car doesn’t drop.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]As Saint has suggested in my previous thread it could be NRV1 and I’m quite confident it is.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]But wouldn’t I lose more than 1-2 psi in 8 hours if NRV1 were leaking? I’m quite confused.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Could it be that something in the block (NRV, solenoid or diaphragm) start leaking only above 105 psi? Like it can’t maintain any higher pressure?[/FONT]
[FONT=&quot]I’ve ordered new o-rings and will strip the block once again. But I would like to have your opinion on this strange behavior.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Thank you for reading.[/FONT]
Click to expand...

I don't suppose it's trying to fill the tank?
 
NicP38 said:
[FONT=&quot]Hi all,[/FONT]
[FONT=&quot]I’m still struggling with my eas compressor running almost continuously (but not burned out yet) as already mentioned in a previous thread.[/FONT]


[FONT=&quot]I’ve tested the line going into the tank with a pressure gauge. The result is: the pressure never goes over 105 psi. Accordingly to RAVE the pump switches on at 7.3 bar (roughly 105 psi) and stops at 9.5 -10 bar. [/FONT]



[FONT=&quot]So that’s the reason why the compressor is always running. It runs and then there is a puff noise, air comes out from the exhaust filter and the compressor starts again.[/FONT]
[FONT=&quot]Leaving the car at night I lose about 1-2 psi in 8 hours which I think is quite normal. The car doesn’t drop.[/FONT]


[FONT=&quot]As Saint has suggested in my previous thread it could be NRV1 and I’m quite confident it is.[/FONT]


[FONT=&quot]But wouldn’t I lose more than 1-2 psi in 8 hours if NRV1 were leaking? I’m quite confused.[/FONT]


[FONT=&quot]Could it be that something in the block (NRV, solenoid or diaphragm) start leaking only above 105 psi? Like it can’t maintain any higher pressure?[/FONT]
[FONT=&quot]I’ve ordered new o-rings and will strip the block once again. But I would like to have your opinion on this strange behavior.[/FONT]


[FONT=&quot]Thank you for reading.[/FONT]
Click to expand...

Assuming you compressor is capable of making more than 105psi and that your guage is accurate, the sound is I think the system thinking that cut out pressure has been reached and then venting the gallery, Wammers will know more about that, but if that is so then I would suspect the pressure switch has lost it's hysterisis, in other words the cut in and cut out points are too close together.
 
Yes I think it's trying. But over 105 psi you can hear a puff noise and then air escapes from exhaust filter ... and starts over again
 
Last edited:
dave4x4 said:
Unscrew the silencer and put your finger over the hole while the compressor is running.
If it is leaking then your diaphragm is u/s.
Click to expand...

No it's not. The compressor stops. And than the air comes out and it starts again. but when running no air comes out
 
It sounds as though NRV1 is OK. It's purpose is to hold tank pressure. Which you say it does more or less. The vehicle also doesn't drop.

The problem to me points towards the air compressor and/or the pressure switch. You say the pressure switch is new, so what condition is the compressor?
 
The Mad Hat Man wrote:-
Can yu test the compressor out of the motor? if so, how?
Click to expand...

Not easily.

I have built my own test rig for testing valve blocks and compressors.
It required buying a section of an old p38 wiring harness and I also had to build a switch box to manually control each individual solenoid. A lot of work but then I am retired. However it now makes it very easy to check the valve box and air compressor on the bench.

As a rule of thumb the air compressor if it is in good nick should compress from zero to 10bars or so in 6 or 7 mins.

Dave
:)
 
dave4x4 said:
It sounds as though NRV1 is OK. It's purpose is to hold tank pressure. Which you say it does more or less. The vehicle also doesn't drop.

The problem to me points towards the air compressor and/or the pressure switch. You say the pressure switch is new, so what condition is the compressor?
Click to expand...

Yep. Pressure switch is new (but from s..tparts :eek:). Compressor is old but I've changed seal and cylinder and o-rings 5 months ago. After fully depressurizing the system it pumps pressure back to 105 psi in about 6 minutes. I think it's not that bad. But maybe it's time to go for a new one.
 
New compressor is megabucks. Unless you are a Swiss banker I would buy a cheap s/h compressor and put new seals in it again. Use it as a spare. I think I would also buy a new pressure gauge just to be sure.
 
dave4x4 said:
New compressor is megabucks. Unless you are a Swiss banker I would buy a cheap s/h compressor and put new seals in it again. Use it as a spare. I think I would also buy a new pressure gauge just to be sure.
Click to expand...

:) swiss but not banker. I will start with a second hand pressure switch and a new gauge to test my new gauge :rofl:
 
I don't need to do that because I just plug a spare compressor into the test harness I have.

I have read that you can connect a battery directly to the compressor.
One of the wires is to the high temp sensor. I understand you can damage it if you connect it wrong. Do a search to check. You can also check I think by the thickness of the wires. The compressor pulls a lot of amps when it runs.

Dave
 
NicP38 said:
Yep. Pressure switch is new (but from s..tparts :eek:). Compressor is old but I've changed seal and cylinder and o-rings 5 months ago. After fully depressurizing the system it pumps pressure back to 105 psi in about 6 minutes. I think it's not that bad. But maybe it's time to go for a new one.
Click to expand...

I would still say the problem is the pressure switch, especially if it's from ****part, compressor sounds OK but could be leaking from the non return valve under pressure:)
 
If the pressure gauge is accurate. Problem can only be pressure switch. If compressor was overheating it would shut down in exactly the same way as it does on reaching pressure. But it would not start straight away. You can run compressor off car by supplying Green wire [positive]. Black wire [Negative]. Under NO circumstances must live [positive] be put to Orange wire, that will destroy thermoswitch. To check thermoswitch is closed circuit [normal] test continuity of black wire and orange wire. If you run compressor on bench and connect a gauge directly to it you should see 175psi + in a few seconds. If circuit is only ever showing 105 psi then compressor shutting down and there is no pressure drop before it restarts. It can really only be pressure switch.
 
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