Another p38 air suspension problem

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T

tonys.dhse

New Member
Posts
46
Location
warrington
hi range rover fans
basically the compressor is not runing as it should been absolutaly totaly fine till the uthere day now it will run for about 20 seconds then stop for about 5 min then run for about 20 seconds again.
i puled to relay out and bridged the feed and the pump runs ok.
any advice would be realy apreciated.
thanks tony
 
Maybe it only needs to run for 20 seconds if the suspension is at the correct height and there are no leaks. Or are you saying the suspension does not lift?
 
sorry guys ye
suspention has been working ok no problems at all the uthere day went to pick some shopping up lowerd car right down bit easyer for mum to get in the would not come back up orange standerd ride hight light just flashing had to drive home with it on bump stops.
found out about jumping the relay.
so car was runing orange standerd ride hight light flashing i jumped realy and pump was runing constent and as the pump was running the car started to lift back up to standerd hight and eventualy orande light was on permenant.
so ovesly the pump has not been runing for a few days and over time it has used all the air out of the tank.
i have not tuched the car for 2 days now and it is still sat there on standerd hight it as not droped down at all so i dont think i have a leek any where.
tony x x x
 
Derek Ward said:
Sounds more like the relay than anything else. Would suggest changing that first and see how you go.
Click to expand...
yes i will try the realy to be honest i have not tride another one yet
was not to shore witch one to use any surgestions witch realy to use am a bit worried about pulling the wrong one out and f--king somthing els up
tony
 
hi ok i swaped the relay but no difrent but i have notested.
ovesly the uthere day i jumped the relay and eventualy the car rose the standerd ride hight.
went out for a run to see what was happening after a few miles the car endid up back on the bump stops ovesly as all the air was used up i have ton say when the car is left for a few days it dose not sink down at all so i dont think there is a leake.
any way it ended back on the bump stops got back home and the pump was not runing at all it would cut in for about 20 seconds.
any way the car was on the bump stops i just left it.
come to it this afternoon started the car and the pump was runing and it cept runing and the car eventualy rose off the bump stops and eventualy reached standered ride hight and a few minits later the pump stoped runing .
so i prested the button on dash to acesse mode and the car droped down ok.
i prested the button again for standered ride hight but nothing car stayed on bump stops and pump would not run so i jumped the relay again and pump runing the car eventaly rose up again.


it seems once the pump has been runing and has warmed up i dose not like runing again unles u jump the relay
i am going to leave it over night and see if it runs in the morning when it is cold.
been reading on hear and the internet that if the pump is getting worn it starts to draw to much current and the ecu shuts off the power feed any body heard of this and my rangi is a year 2000 with 115000 miles and the date on the pump has year 98 on it so pump is quit old
what do u think guys
tony
 
finaly got out to do some more investigations
tested the thermal switch that is ok
went to test the presure switch tested the switch after the car has been left for a few days tested pin 7 and 9 had a open circuit started the pump runing and after it had been runing for about 10 min tested the switch again and it had not changed indicating the system is still not up to presure started the pump runing again and to be honest with keep cheaking switch the pump must of been runing for over 30 min but presure switch still not changing i jumped the relay the keep the pump runing
how long dose the pump need to run to charge the system.

even after the car has stud for a few days it dose not drop down so i dont think there is a leak any where.
also when the pump was runing i rempved the filter and put my finger over the hole did not get much of a vacum there was some but not very strong
should there be a realy strong vacum ?
because i have a feeling that the pump is not able to get the system up to full presure.

any feed back would be great full
thanks tony
 
hi ok i swaped the relay but no difrent but i have notested
Click to expand...

Does that mean you did test it or not?

how long dose the pump need to run to charge the system.
Click to expand...

Around 10 minutes or so depending on how worn your pump is.

come to it this afternoon started the car and the pump was runing and it cept runing and the car eventualy rose off the bump stops and eventualy reached standered ride hight and a few minits later the pump stoped runing .
Click to expand...

Sounds normal.

been reading on hear and the internet that if the pump is getting worn it starts to draw to much current and the ecu shuts off the power feed
Click to expand...

Not true. The ECU doesn't monitor the current the motor takes. There is a thermal switch that monitors the temperature of the motor and this will open on high temperature to give a signal to the ECU to stop the motor.

As far as I know, there's only 2 signals to the ECU that will stop the pump running and they are the pressure switch and the overtemperature switch. Other signals to the ECU such as brake pressed / handbrake on etc affect the operation as in whether the car will move up or down when you select whatever height you want. Eg height changes are suspended when you press the brake (unless you keep it pressed for more than 3 minutes).

So, when the pump stops after 20 seconds or so, it can only be due to one of the following reasons:
1) It's up to pressure or the pressure switch is closing too early.
2) The motor's getting too hot or the temp switch is opening too early.
3) The pump relay is knackered (high resistance contacts / dropping out).
4) The ECU is switching off the pump relay because it thinks 1) or 2) above is happening.
If you're sure all of the above are performing as they should, the only thing left is the ECU. I think it would be unlikely though still possible.
 
hi m8 not to shore how to do the quote think

but the relay there was a few relays in the box that are identical so i just swaped em round so there i a difrent relay in there now so i know that is ok.

regarding pump re charging system as the pump was runing there was not much of a vacum i found out of rsw solutions how to teat the presure switch and the thermal switch.
as for charging the tank back up i must have had the pump runing well over 30 min and the presure switch never triped.
ithere the presure switch is ithere faulty or the pump is unable to get the presure up enof to trip the presure switch.
even thow the pump was runing for so long the thermal switch never triped so i know that is ok.
i have just sent of for a cable and eas soft ware from rsw solutions it may be the system has loged a fault and just needs clearing.
tony
 
Even so, with the pump running for so long, it should come up to pressure. There's an air operated diaphragm valve in the valve block that I believe has been known to fail. If that's the case, the compressor will just be blowing straight out to atmosphere via the silencer which is mounted below the valve block (that's if I'm reading the pneumatic drawing in Rave correctly).

So you could still have one of a variety of faults - mechanical in the valve block, electrical in the valve driver or electrical in the EAS ECU.
In desperation whilst you're waiting for the lead and software, you could always unplug the ECU to try and 'reset' it. Unlikely to do anything but it won't cost you anything to try either. Failing that a replacement ECU from fleabay?
Pump wise, you could try running that on the bench to see if you can get pressure out of it.
Whereabouts are you anyway? Always helpful to put your location in your profile. There may be someone nearby who can help.
 
hi m8 will take the pump off at the week end and try it on the bench see if i am getting much presure out.
i dont know if it helps but the car never drops down if left for a few days so no leeks in suspention.
but if i pres the switch and drop the car down to the access mode after the car has droped down and i press the switch back to standerd hight nothing happens because the pump is not runing.
if i jump the relay and get the pump runing eventualy the car will start to rise slowly and eventauly reaches the correct hight.
if i leave the pump runing the car will carry on and rize to the highest setting on its own but if i test the presure switch it has still not tripped.
when i was looking at the vidio from rsw solutions when the system is under presure there is an open circut and when the corect presure is reached the switch is closed and i am not getting a closed circut at all so ithere the presure switch is faulty of the pump is not strong enof to reach the right presure to trip the switch
i live in warrington
thanks tony
 
Tony,
If the pump was worn out I think you'd have noticed it taking longer and longer to raise the rangey over the past few weeks. From your description, it seems that this came on suddenly. You've tested the pressure switch and it stays open circuit so that is clearly faulty and it much more likely to be the fault because it failed suddenly and when you bridge it the pump runs fine.
I think you'vre cracked it, m8; change the pressure switch. If you need a reading of your EAS I can do that and I'm only 28 miles from you - but change the pressure switch first, I'll bet that'll fix it.
 
ok got a bit farther with this to day got the cable and software this morning and basicaly it showed a fauld (rl sencer out ) cleared the fault and it never returned but eas still not right lowered car to bump stops and then presrd switch to rase back up but nothing hapening because pump not runing.
jumped relay and pump runing and car came back up.

now i suspected a fault with presure switch because it was not tripping but to day i prested the inhibitor switch and left the drivers door open so the suspention would not move at all jumped the relay got the pump runing and after about 10 min tested the presure switch and it had triped so i know this is alright now.

so i know the pump can get the system up to presure even thow it is a bit racaly so pump it working

i know the thermal switch is ok

i now know the presure switch is ok

no faults loged in ecu

so it is looking like a problen with eas ecu because when the presure drops the pump it not beeing run long enof to re presure the system.

any idears where i can go from hear guys

tony
 
A second hand ECU will cost around thirty to forty quid from someone like P38spares on ebay. I got one from them and it worked fine (although needs calibrating). I think that's maybe your next thing to try. When you've been trying the pump with the engine running and the door open, is the relay definitely operating? You should hear/feel it click open and shut as you remove/replace it. If it isn't doing that, the ECU is obviously not telling the pump to run and. as far as I know, the only thing that would cause that (other than a duff ECU) is a closed pressure switch (just to make sure - the switch is CLOSED when the pressure is 10bar (140psi).
There's an ECU here:
EAS Air Suspension Ride Height ECU - ANR4499 on eBay (end time 01-Mar-10 22:00:46 GMT)
 
Derek Ward said:
A second hand ECU will cost around thirty to forty quid from someone like P38spares on ebay. I got one from them and it worked fine (although needs calibrating). I think that's maybe your next thing to try. When you've been trying the pump with the engine running and the door open, is the relay definitely operating? You should hear/feel it click open and shut as you remove/replace it. If it isn't doing that, the ECU is obviously not telling the pump to run and. as far as I know, the only thing that would cause that (other than a duff ECU) is a closed pressure switch (just to make sure - the switch is CLOSED when the pressure is 10bar (140psi).

yes m8 the switch should be closed when the presure is reached and i am getting that if i have the car going down then back up to use some of the air to drop the presure the switch is opening but the pump is not runing some times it will run for about 20 seconds but the switch is still open.
with the presure down the moter should be runing tested the voltige to the relay from the ecu and nothing it defo looks like the ecu is not sending a signal out to trip the relay i have just checked the wire from the ecu to the relay and that is ok acording to my meater there is no risistence at all so the wire is ok it is pointing more to the ecu.

thanks tony
Click to expand...
 
Look at the where the relay plugs in, it could just be a bad connection at the relay. Look for any signs of heating around the relay socket and the plug in spades that would indicate a bad connection.
 
Hi Tony
Have to agree. If the wire from the ECU to the relay is ok, it has to be the ECU. If I was home at the moment, I could come over with the spare I have but I won't be back for a couple of weeks unfortunately (Only live in Blackburn). Last chance saloon then is one from ebay. Only thing I'd say there is make sure you get one from a known dealer with near 100% positive feedback. I got mine from top_P38_spares
(email [email protected])
He was pretty quick - was advertised with no faults and as far as I can see there isn't. It was £36.75 & £5.95 postage which I didn't think was too bad. There are others advertised of course. Pays yer money and takes yer choice.
 
Could it be that the electric motor part of the air pump is faulty? Sounds like your`s is 2nd hand replacement anyway? Marked 1998? Anyway it can happen that the commutator copper segments can be damaged by worn out brushes: the motor can stop where no contact is being made, but going over a bump, or tapping the motor will jog it around enough to make a contact and restart. It is possible to examine the brushes, BUT very awkward to re-assemble the motor. How about removing motor/pump and connecting 12v supply; the pump should run ; try it at many (20?) times. If it always fires up, then ok, but if it hesitates, and goes only after a shake then you`ve found your fault. Any comments on this idea?
 
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