pipes, compressor, bags, fuse and a relay!
 

Hi all

I have a very quick question after having read quite a few threads on here regarding troubleshooting a leak in the air suspension system.

where are the frikkin pipes?? :Confused:

I am trying to troubleshoot this issue with my 2007 3.0 TDI A8 and have thus far managed to establish:

the 40 amp fuse in the passenger footwell is fine
I have changed the relay in case

please help.

Also is it true that if I want to test the compressor/pump I can do so from the relay location by giving it live and ground to the correct terminals?

thanks all in advance.

In order to diagnose your problem and any other general tinkering on these cars you would be wise to invest in vcds cable and software so you may scan for faults and test components on the car.

I'm not at home just now but I can upload some info on the suspension systems later or try googling for Audi a8 suspension ssp and and you will likely find a good explanation of the systems.

Hi Del

thanks for the info. I should have mentioned that i've had the car scanned and it did come up with suspension errors, one of which was 'leak detected in system'.

I've managed to test the relay and all is good there, but i'm trying to figure out how to actuate the pump.

Anyway, i've managed to remove the wheel and the liner, just about to try and remove the pump. I think Glyn did a write up of how to do that.

I'm quite sure you could manually trigger the compressor but its much better to do these tests with vcds as you can see the output pressure, temp, and function each strut through a sequence of output tests which may help you find the fault quicker and easier.

Managed to get to the pump connector and figured out which cables are for power (brown one and red+white one), wired a battery to it but nothing.

Does this mean it's dead?

If I remove the pump can I still drive/move the car or not? if not is that because the pipe circuit is broken and hence will not be 'air tight' ?

Also once the pump is removed will the car then lower all the way to the ground?

thanks in advance

Looking at the schematic in that attachment if the car tries to raise its self with the compressor remove it will drop to the floor as the will be nothing downstream of the solenoid block to prevent the air escaping.

If the car is still at a sensible ride height you could disconnect the cabling from the valve block, that would prevent the air springs from discharging providing there is no leaks of course.

There is something else you could possibly try but I can not say for sure, if you go into the mmi and put the car into jacking mode then it should not try to adjust the air in the system but you can not go above 9 mph so its not going to help if you have to travel in the car and would be best if you disconnect the wiring from the valve block.

Thanks again for the reply Del.

I've parked the car in such a way now that its not obstructing and so can stay overnight on a axel stand if necessary (or I can put the wheel back on).

I am going to attempt the removal of the compressor as I think it is suspect.

Incidentally where is this valve block you speak of?

PS I do have the car in Jacking mode anyway to be on the safe side, however I understand it may not be wise to drive the car until the compressor is back on the car.

Also does anyone know how loud this compressor/pump is when it is working? should I be able to tell easily that it is running/on?

Not sure if anyone else is following this but here's an update. :)

I've managed to finally remove the compressor/pump - following a write up which a previous member wrote on this forum, available here - many thanks to Glyn. +++

The write up makes more sense once you've done the job (if that makes sense), it's a little hard to do, but I managed it okay and i'm no mechanic!:tuttut:

Anyway, whilst the compressor was on the car I did try to actuate it by putting a +12V feed to it from a motorbike battery, and also the ground, but had no luck.

So just as I had put everything away (it had gone dark!), I wanted to settle my curiosity - I took the battery again and put the feed to the compressor; this is done by using the lowest of the three connectors. And what do you know?? the thing comes to life and starts choo choo-ing like a little train. :ROFL::ROFL:

So; this means that the compressor is good. What does come to mind is that one of the VCDS scan errors mentioned something about shutting the compressor down due to something, so I wonder if the reason why it didn't actuate when I gave it the feed, whilst on the car was because it had the other two connectors still connected? in other words there is some condition which is causing it not to come on?

anyway, I'm still learning and quite puzzled.:Confused::Confused: Hope this has helped someone, and if anyone cares to explain this a little more, I for one am all ears!

The fact the motor is still working is a good thing, you need to find the soruc of the leak and fix that.

Your compressor may still be worn out but as you have not posted a log from vcds or run output tests its difficult to say what the status is.

Theres a guy on ebay called bag pie andy that sells a seal kit for your compressor and it may be worthwhile to replace it as you have the compressor out already.

I have a gut feeling that you have an air leak by what you have said and the system has shut off.

There was another forum member with suspension issue that said it was shut off but there was never any real conclusion.

Hi Del

Thanks again for following the posts and replying.

Deffo good news about the compressor - man that thing was a nightmare to get out! (ended up purchasing some L type keys with Torx ends, a bit like allen keys) - wish I had had these for the job.

Anyway, I was also thinking about getting the bagpipe kit, but didn't know how to check if the piston ring thingy needed replacing? but yes, it certainly makes sense to spend the £20 odd quid since I have it out already.

The guys that did the scan for me printed out the logs for me, so I will see if I can take a snap and upload them. But yes it would hopefully prove worthy to try and diagnose the issue.

I am going to cancel my appointment with the garage tomorrow, and hopefully see if I can resolve myself... of course with the help of fellow forum chums! +++

I have also found these threads but unfortunately some of them do seem inconclusive.

Here are the codes:

(sorry didn't get to host them so its turned out to be two attachments instead).

Now you have it out, you could try and find a local pneumatics / hydraulics supply shop and go round with the pump unit and see if they can adapt the output pipe to a pressure gauge and then you could hot wire like you did before to see what the max pressure is.

A new one pumps out 16 bar max so I anywhere between 10-16 should be fine, lower than that then you would be wish to replace the piston ring from bagpipe andy.

God luck

Can anyone shed any light on the error codes?

Also there are two pipes which you remove from te compressor, when pressure testing it does one need to be capped off?

Thanks in advance

If you look at the schematic on page 18 of the ssp i attached earlier you can see the compressor 1, which pumps through the air drier (2) and then through (3A) non return valve.

So to test the unit you have to fit a pressure gauge onto the output line that normally connects to the Valve block down stream.

The normal position for the valves within the compressor are closed with no power to them which is great as it makes testing easy.

Once you have a gauge attached to the output, hot wire the motor as you did before and you should get a reading on the gauge.

The fault codes are quite generic and don't really say much as it could be telling you there's a leak or it may be that the pumps just worn out and the lack of pressure is giving the same error, In an ideal world the compressor would never wear out and the system then could say for sure there was a leak as it can't get the pressure to where it needs to be.

Only other way the system could say if there was a leak is via the height on each strut, but its more likely to be the compressor as they are well known to wear out.

Mines only done 50K and its already down to 10bar.

Having looked at the pump/compressor again, I realised that there is only one rubber pipe, which comes out vertically (though yes it is connected twice to the pump). I don't understand the schematic if i'm honest, so a bit stumped there.

Anyway another update:

took the pump down to a local guy who repairs gas systems for refridgerators and the like. He offered to put a gauge to it, and initially it looked like the needle on the gauge was pulling back, as if to show suction as opposed to pumping air out? he also suggested something to do with a one way valve, but I'm already confused! :ROFL:

Anyway, after a little while the pump decides not to work again! (and this is consistent with when I tried to give it a 12V feed whilst it was still on the car, I could swear it didn't actuate). So me and him both baffled we tested the wire further down the pump by piercing it with the probes from his multimeter, and yes there was power/current there.+++

The guy then concluded that the motor must be duff and suggested that I look at it. He actually encouraged me to open it and showed me what I would need to do.. so guess what? I did:

http://i23.photobucket.com/albums/b3...9398940728.jpg

http://i23.photobucket.com/albums/b3...36167757EA.jpg

So as can be seen, most of the inside of the motor is a mess. The bushes (I believe that's what they're called? the 2 spring mounted metal things? seem to be okay.

I'm thinking to open the other side where the riveted panel is (the side with the crankshaft?) to see if I can open it more?

what do you think Del/Others? :cool:

+++

That doesn't look good, is thats whats left of the electrical connection?

If you or you gas guy has a read through the attachment I was on about there is pictures with numbers showing the pressure connection and suction ( Air in side)

Update:

RESULT! +++

After spend mucho time on this mini DIY fix it job, I have finally had a result and I'm delighted!

Turns out the one of the springs behind the brush had lost its 'springiness'. As a result the motor was going bad. The gas guy (who is now my friend!) said he'd previously helped a guy with a Q7 who had had a similar problem.

It turns out this guy with the Q7 works in/owns? the garage next door (tyres and exhausts place), and apparently still has all the spare bits lying in a box somewhere. His Q7 had other issues to from what I was told, and I'm not sure he had fixed the issues.. So my new friend suggested that I go around there and ask if this chap still had the spare bits from his motor.

Sure enough, I got the box (just gave it to me), and was about to swap one of the springs over, then decided to just swap the whole side section out (the part of the motor which has the two power cables running into it. Its a little tricky as you have to somehow retract the two brushes and the springs behind them before you can fit it onto the spindel of the commutator.

Finally got the motor working, and managed to get some air pumping. Although I couldn't get a proper reading, I tested it by placing my index finger over the output hole, and it was decent. Andy from bagpipingandy suggested this technique and said not to worry about getting an exact pressure reading.

So.. managed to put the whole thing back together (I had taken pics as I knew I would forget! :D )

Mounted it back onto the car, tested it by manually actuating the relay, and hey presto! we had a working compressor!

Switched the engine on for the moment of truth.. nothing.

Remembered car was in jacking mode, switched this off, straight away something, and then all the options become white from being greyed out, and its working again!!!

In summary, Delboy was right on the money when he said:

"The fault codes are quite generic and don't really say much as it could be telling you there's a leak or it may be that the pumps just worn out and the lack of pressure is giving the same error"

I believe that because the motor was on its way out and behaving, at best, intermittently, this was the cause for the errors.

The lights have gone out themselves, and I just need to get VCDS scan again to see if the errors have gone away.

I do feel that the kit from bagpipingandy would make it pump more pressure, but not sure how this would affect the air suspension? would it raise and lower the car any quicker?

Also, I was thinking to wire a buzzer or a light to the relay, in order to monitor how often and for how long the compressor is kicking in; mainly because I want to prevent it from heating up/burning out. That said, both my fuse and relay were fine.

Thanks to all those who read my posts, and especially to Delboy +++

Hope this has helped someone..

....shopping list now needs a VCDS cable and software adding to it! :cool:

Good news fella, glad your cars back UP and running.

That green corrosion looks like there's been some manky water getting in around the end of the motor. :tut tut:

Keep a close eye on it over the next day or two because if there is a leak in the system your compressor will be on off too much and overheat.

Once you get settled into the car and purchase vcds you will then be able to see the pressure the system has.