Rudolf

Member
Evening guys.

So…. A couple of weeks ago I noticed the EAS pump running a lot in short bursts. From start up or from any height increase it runs on and off in about 4 second bursts, this might go on for 15 minutes before it settles down. In all other respects the system works perfectly. I can’t find any leaks and she doesn’t lose height when parked. I rebuilt the compressor but to no avail. Do any of the esteemed fraternity have any thoughts?
 
Evening guys.

So…. A couple of weeks ago I noticed the EAS pump running a lot in short bursts. From start up or from any height increase it runs on and off in about 4 second bursts, this might go on for 15 minutes before it settles down. In all other respects the system works perfectly. I can’t find any leaks and she doesn’t lose height when parked. I rebuilt the compressor but to no avail. Do any of the esteemed fraternity have any thoughts?
Is this with the bonnet open?
 
Loose wire? Have you tried recording a trace using diagnostics?
 
Will it not show which circuits are open and if it really is running erratically? I'm thinking thermal switch here.

Guess worn brushes might also cause sporadic start-up. Or dodgy connector block.
 
Will it not show which circuits are open and if it really is running erratically? I'm thinking thermal switch here.

Guess worn brushes might also cause sporadic start-up. Or dodgy connector block.

Compressor circuit is a bit basic on diag. If the thermal switch is duff it's usually totally duff it does not do a slight fail usually. Checking connections to pressure switch maybe an idea, that is the only thing in the valve block that has any effect on the compressor circuit. Even then it's an indirect link. The pressure switch has a narrow working band, compressor on 120 psi +- 7 psi. Off 140 +- 7 psi. So if it's getting duff the differential on to off, off to on can be quit low. Or quit high if it has varied in the other extreme. You would need a slight leak as suggested earlier to spring it into action though.
 
Compressor circuit is a bit basic on diag. If the thermal switch is duff it's usually totally duff it does not do a slight fail usually. Checking connections to pressure switch maybe an idea, that is the only thing in the valve block that has any effect on the compressor circuit. Even then it's an indirect link. The pressure switch has a narrow working band, compressor on 120 psi +- 7 psi. Off 140 +- 7 psi. So if it's getting duff the differential on to off, off to on can be quit low. Or quit high if it has varied in the other extreme. You would need a slight leak as suggested earlier to spring it into action though.
RAVE gives a cut in pressure of 104 to 116 psi cut out pressure 138 to 152 psi so maximum differential is 48 psi, minimum differential 22 psi.:)
 
RAVE gives a cut in pressure of 104 to 116 psi cut out pressure 138 to 152 psi so maximum differential is 48 psi, minimum differential 22 psi.:)

Suppose that depends on which part of RAVE you read. Pressure switch in electrical diagrams is listed as low 8.5 bar 120 psi and high 10 bar 140 psi. Actually 8.5 bar is 124.95 psi and 10 bar is 147 psi. So i think for illustrative purposes the round 120 and 140 works pretty well. I mean Land rover don't even know that a bar is 14.7 psi so you can't expect total accuracy everywhere. :D:D
 
Suppose that depends on which part of RAVE you read. Pressure switch in electrical diagrams is listed as low 8.5 bar 120 psi and high 10 bar 140 psi. Actually 8.5 bar is 124.95 psi and 10 bar is 147 psi. So i think for illustrative purposes the round 120 and 140 works pretty well. I mean Land rover don't even know that a bar is 14.7 psi so you can't expect total accuracy everywhere. :D:D
120+/-7 psi & 140+/- 7 psi could give a differential of as little as 6 psi, pretty unlikely I think, there is no indication of pressure in the wiring diagrams in my version of RAVE.
 
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120+/-7 psi & 140+/- 7 psi could give a differential of as little as 6 psi, pretty unlikely I think

Unless you have a slight leak on NRV1 and the pressure switch is duff then you may get compressor running quit often don't you think?
 
The quoted 8.5 bar is 124.95 psi. -7 = 117.95 psi. +7 = 131.95 psi. 10 bar is 147 psi. -7 = 140 psi. +7 = 154 psi. So the highest differential can be 36.05 psi and the lowest 8.05 psi. :);)
 
The quoted 8.5 bar is 124.95 psi. -7 = 117.95 psi. +7 = 131.95 psi. 10 bar is 147 psi. -7 = 140 psi. +7 = 154 psi. So the highest differential can be 36.05 psi and the lowest 8.05 psi. :);)
RAVE quotes a cut in figure in Bar of 7.8 to 8 bar (114.6 to 117.6 psi), cut out 9.5 to 10.5 bar (139.65 to 154.35 psi) based on your figure of 1 bar = 14.7 psi. Minimum hysteresis 22psi. Nowhere in my versions of RAVE does it mention +/- 7 psi.
An 8 psi hysterisis would be pretty ridiculous, the pump would be cutting in and out all the time.
 
RAVE quotes a cut in figure in Bar of 7.8 to 8 bar (114.6 to 117.6 psi), cut out 9.5 to 10.5 bar (139.65 to 154.35 psi) based on your figure of 1 bar = 14.7 psi. Minimum hysteresis 22psi. Nowhere in my versions of RAVE does it mention +/- 7 psi.
An 8 psi hysterisis would be pretty ridiculous, the pump would be cutting in and out all the time.

Somebody should have told the technical illustrator who did the wiring diagrams then. And advised him what a bar was. To many anomalies and contradictions. So if the compressor is supposed to cut off at between 9.5 bar and 10.5 bar. Nominal would be 10 bar, half a bar is 7.35 psi. Near enough to +- 7 psi for me. Seeing as Land rover seem to think a bar if 10 bar = 140 psi is 14 psi it would be exactly +- 7 psi what do you think? Get your glasses on lower figure is 7.2 to 8 bar.
 
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120+/-7 psi & 140+/- 7 psi could give a differential of as little as 6 psi, pretty unlikely I think, there is no indication of pressure in the wiring diagrams in my version of RAVE.

Look at the diagram for the pressure switch. It states [0] < = 8.5 bar 120 psi. [1] > = 10 bar 140 psi. Every version of RAVE shows this from 1995 to the last one edition 20.
 
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