Range Rover P38 help needed please
Discussion
The air suspension on my P38 range rover was getting a bit lazy last year, and eventually gave up altogether. Turned out the air compressor needed replacing and this was done in October 2010. A month ago I was leaving work and the suspension refused to lift properly, so I took it back to the garage that did the work (they actually subcontracted the job to a 4x4 specialist). After a month of faffing about, and lots of finger pointing, and new compressor was installed today. When connected up it buzzed away, but the suspension didn't lift. Now the second compressor has stopped working altogether, and the garage was unable to get it working with a power probe. They now suspect that the replacement compressor has burned out.
Help! Can a compressor really burn out in a minute or two? Could there be something wrong with the car that is causing this? I appreciate that if the air suspension system is leaking air it would reduce the life of the compressor, but not to a matter of minutes. Any help appreciated.
Help! Can a compressor really burn out in a minute or two? Could there be something wrong with the car that is causing this? I appreciate that if the air suspension system is leaking air it would reduce the life of the compressor, but not to a matter of minutes. Any help appreciated.
I wouldn't have thought a compressor would become 'lazy', generally it's because the system is leaking somewhere, and they can and do leak on P38's
I also wouldn't expect a compressor to die in minutes unless it was racing away against no pressure at all, which would mean a catastrophic leak just downstream of the compressor
I also wouldn't expect a compressor to die in minutes unless it was racing away against no pressure at all, which would mean a catastrophic leak just downstream of the compressor
The car is a 1998 vehicle in very good condition. The are no leaks inthe airsprings as far as I know. I feel like the garage is trying to fob me off by saying that something on the car is causing the compressor to burn out. I just don't see how it could happen in a couple of minutes.
tomsugden said:
The car is a 1998 vehicle in very good condition. The are no leaks inthe airsprings as far as I know. I feel like the garage is trying to fob me off by saying that something on the car is causing the compressor to burn out. I just don't see how it could happen in a couple of minutes.
We had a 2001 P38a from new that was in great condition when we sold it at 3 years old. It'd been serviced properly, and was generally the most reliable Range Rover we've had (out of 7 in 25 odd years). About a month before we got rid of it, I helped a mate move out of his room at Uni and loaded it up to the gunnels with the suspension dropped for easy access.When we got in it to drive off, we discovered it wouldn't raise unless all three of us got out of it. You could hear the compressor pumping away fine, trying to lift it, it was clearly a leak somewhere.
I'd suggest getting it tested somewhere else, they are notorious for leaking and the compressor is probably the most expensive part in the system by some margin, which may indicate the motive of your garage...
Do your self a favour, get shot of the air suspension and get them to fit shocks and springs, trust me in the long run it will save you money.
(spent over £2K trying to get mine sorted, and pretty much every part with new items, and it would still randomly drop its arse on the bump stops)
(spent over £2K trying to get mine sorted, and pretty much every part with new items, and it would still randomly drop its arse on the bump stops)
My advice would be this:
1. Do some reading up on the air suspension. It's really not as scary or complex as it first seems. This will help you understand what the garage is doing wrong or right.
2. If the garage don't understand it. Don't use them. I know this doesn't help right now. But if they are buggering it up thy evidently don't know.
3. Leaks are the main issue with air suspension. This causes the pump to run all the time and wear out. This won't happen in a couple of mins though. That is either a fault with the unit or they did something wrong.
4. If it was lazy, I suspect it was not really the pump.
5. Air suspension can suffer with water due to condensation. There should be some plugs you can remove and run the air compressor. It should get rid of the water from the system.
1. Do some reading up on the air suspension. It's really not as scary or complex as it first seems. This will help you understand what the garage is doing wrong or right.
2. If the garage don't understand it. Don't use them. I know this doesn't help right now. But if they are buggering it up thy evidently don't know.
3. Leaks are the main issue with air suspension. This causes the pump to run all the time and wear out. This won't happen in a couple of mins though. That is either a fault with the unit or they did something wrong.
4. If it was lazy, I suspect it was not really the pump.
5. Air suspension can suffer with water due to condensation. There should be some plugs you can remove and run the air compressor. It should get rid of the water from the system.
Edited by 300bhp/ton on Tuesday 15th March 13:41
From memory and huge costs on the 4.6 I had, if you have the slightest leak, the pump will work overtime to keep pressure in the system and LR in their wisdom never fitted a relay or any overheat protection to stop this. So the pump will work and work and work until it dies or reaches pressure.
This is what I was told by a specialist.
This is what I was told by a specialist.
KrazyIvan said:
Do your self a favour, get shot of the air suspension and get them to fit shocks and springs, trust me in the long run it will save you money.
(spent over £2K trying to get mine sorted, and pretty much every part with new items, and it would still randomly drop its arse on the bump stops)
If you go down this route be careful what shocks and springs you fit. Some of the conversion kits are notoriously hard and have a shocking ride.(spent over £2K trying to get mine sorted, and pretty much every part with new items, and it would still randomly drop its arse on the bump stops)
My Classic has been converted and suffers from this. I am changing them for some better quality items.
not sure how much help this is, but find somebody who understands these cars. Where are you?
I has a late classic with air susp. 4 days after I bought it, the suspension failed. Unlike some, rather than complaining on here, I tried to get it fixed.
A Land rover specialist in pool (I was on holiday there) spent half a day on it and told me that the susp computer was F*cked and he couldn't interogate it to find the problem, so it needed a new one at 500 odd notes.
Got it home (RAC) and had a look at it myself and quickly found a pipe with a hole in it. Soon fixed with a half a Bic pen and some araldite. Called around locally and found a man to trust. He reset the on-board computer for £30 at the first attempt.
Morale - just because a garage claims to be specialist doesn't mean they know their A*se from their elbow.
I has a late classic with air susp. 4 days after I bought it, the suspension failed. Unlike some, rather than complaining on here, I tried to get it fixed.
A Land rover specialist in pool (I was on holiday there) spent half a day on it and told me that the susp computer was F*cked and he couldn't interogate it to find the problem, so it needed a new one at 500 odd notes.
Got it home (RAC) and had a look at it myself and quickly found a pipe with a hole in it. Soon fixed with a half a Bic pen and some araldite. Called around locally and found a man to trust. He reset the on-board computer for £30 at the first attempt.
Morale - just because a garage claims to be specialist doesn't mean they know their A*se from their elbow.
Spoof said:
From memory and huge costs on the 4.6 I had, if you have the slightest leak, the pump will work overtime to keep pressure in the system and LR in their wisdom never fitted a relay or any overheat protection to stop this. So the pump will work and work and work until it dies or reaches pressure.
This is what I was told by a specialist.
Which just goes to demonstrate what a load of old bThis is what I was told by a specialist.
ks people will spout when they don't understand how something works 
The pumps do have an overheat cut-out built into them. There are 3 wires that physically connect to the pump itself. An live, a ground and a overheat indicator that the suspension ECU monitors to stop the pump being used when it's overheated.
Normally, the sensor wire will appear as short circuited to the ground wire within the pump. When the pump overheats it open circuits the sensor wire (yellow iirc?) from earth and the ECU 'sees' this and will not apply power to the pump until the pump returns to short circuit again.
Now, I had the exact same as the OP and bought a second pump which made no difference to my car occasionally sinking to the bump stops. So after some 'net surfing I wired in a swtich and a couple of lights so I could override the overheat function of the pump and see when the system was at full pressure and when the pump was actually running.
Turns out that there wasn't actually anything 'wrong' with the car, but my short journeys, coupled with it being parked on uneven surfaces at both ends meant the system was needing to be re-charged at every little journey. The pump would then overheat and becuase it seems to take the pumps a day or so to return to 'cool' status, it was making my car run out of compressed air and the suspension collapsing slowly.
Thing is, when the pumps go to 'overheat' they are barely warm to touch, so I've just bypassed the overheat sensor and all is well now. I have a light to keep an eye on the pump so i can check that it isn't actually running all the time, and I have a light where I can see that the reservoir has reached full pressure. Those lights tell me the system is working fine.
Watching the lights , it's worth noting that the pump can sometimes need to be running for about 5 mins to recharge the bottle, which is fine, but if you do a lot of stop start... or have a leak in the pipes/bags... then it's going to be working often... and it will go to overheat... and then it will take about a day to go back to 'cool' before it can be used by the car again.
Hope this helps
Seems to me the OP probably has a leak, or possibly a dodgy height sensor, which is making the system have to re-charge often and then overheating the pump.
ETA - you can very quickly suss out if the pump is working or not by removing a relay form the fusebox under the bonnnet (no. 20?) and shorting out the 'power' pins with a bit of wire. Check this out on google, loads of sites telling you exactly how to do this. I can guarantee you pump will fire up when you do this as it temp bypasses the overheat sensot in the ECU!
Edited by Piersman2 on Tuesday 15th March 14:05
I had one of these useless vehicles. The air suspension system was the bane of my life. I'd be more suspicious of the main valve body than the compressor. Mine failed twice in the space of a year.
They are crap and really susceptible to solid particulate contamination from the system up-stream of it. One little bit of grit and you're in limp-home mode....... again.
They are crap and really susceptible to solid particulate contamination from the system up-stream of it. One little bit of grit and you're in limp-home mode....... again.
Piersman2 said:
Spoof said:
From memory and huge costs on the 4.6 I had, if you have the slightest leak, the pump will work overtime to keep pressure in the system and LR in their wisdom never fitted a relay or any overheat protection to stop this. So the pump will work and work and work until it dies or reaches pressure.
This is what I was told by a specialist.
Which just goes to demonstrate what a load of old bThis is what I was told by a specialist.
ks people will spout when they don't understand how something works The pumps do have an overheat cut-out built into them. There are 3 wires that physically connect to the pump itself. An live, a ground and a overheat indicator that the suspension ECU monitors to stop the pump being used when it's overheated.
Normally, the sensor wire will appear as short circuited to the ground wire within the pump. When the pump overheats it open circuits the sensor wire (yellow iirc?) from earth and the ECU 'sees' this and will not apply power to the pump until the pump returns to short circuit again.
Now, I had the exact same as the OP and bought a second pump which made no difference to my car occasionally sinking to the bump stops. So after some 'net surfing I wired in a swtich and a couple of lights so I could override the overheat function of the pump and see when the system was at full pressure and when the pump was actually running.
Turns out that there wasn't actually anything 'wrong' with the car, but my short journeys, coupled with it being parked on uneven surfaces at both ends meant the system was needing to be re-charged at every little journey. The pump would then overheat and becuase it seems to take the pumps a day or so to return to 'cool' status, it was making my car run out of compressed air and the suspension collapsing slowly.
Thing is, when the pumps go to 'overheat' they are barely warm to touch, so I've just bypassed the overheat sensor and all is well now. I have a light to keep an eye on the pump so i can check that it isn't actually running all the time, and I have a light where I can see that the reservoir has reached full pressure. Those lights tell me the system is working fine.
Watching the lights , it's worth noting that the pump can sometimes need to be running for about 5 mins to recharge the bottle, which is fine, but if you do a lot of stop start... or have a leak in the pipes/bags... then it's going to be working often... and it will go to overheat... and then it will take about a day to go back to 'cool' before it can be used by the car again.
Hope this helps
Seems to me the OP probably has a leak, or possibly a dodgy height sensor, which is making the system have to re-charge often and then overheating the pump.
ETA - you can very quickly suss out if the pump is working or not by removing a relay form the fusebox under the bonnnet (no. 20?) and shorting out the 'power' pins with a bit of wire. Check this out on google, loads of sites telling you exactly how to do this. I can guarantee you pump will fire up when you do this as it temp bypasses the overheat sensot in the ECU!
Edited by Piersman2 on Tuesday 15th March 14:05
The suspension system is not that complicated but you do need to find someone who understands it and certainly not use a garage that sub-contracts the work elsewhere.
As mentioned, lots of short journeys or raising and lowering it works the compressor pretty hard and it can cut out. Mine sometimes takes a while to rise in the morning but just giving it 5 mins seems to help, esp unloaded. I wouldn't rush to change to springs nor would I buy ex-scrapyard bits for the system since it does seem to fail as a matter of course so second-hand stuff will probably be close to the end of it's life; I just regard it as consumables. Fitting and changing bags is also pretty easy and cheap, the EAS controller is, however, quite pricey.
As mentioned, lots of short journeys or raising and lowering it works the compressor pretty hard and it can cut out. Mine sometimes takes a while to rise in the morning but just giving it 5 mins seems to help, esp unloaded. I wouldn't rush to change to springs nor would I buy ex-scrapyard bits for the system since it does seem to fail as a matter of course so second-hand stuff will probably be close to the end of it's life; I just regard it as consumables. Fitting and changing bags is also pretty easy and cheap, the EAS controller is, however, quite pricey.
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