The link posted is for a Thor. It's the cylindrical thing with 2 pipes that bypass the throttle body.

+1 on the MF31 series. I've got an MF31-1000 on both P38s and an MF31-750 on a boat. Never had a flat battery or problem with any of them.

Looks like the come with the rails and aren't available as a separate part. Rails are NLA.

If you mean the whole dashboard, follow the guide that David H posted. If you just want to remove the instrument cluster, as the other David says, it's a 5 minute job.

A dead accumulator will only cause the warning lights to come on when you hit the brakes. It stores pressure in a sphere with a diaphragm across the centre with Nitrogen at high pressure behind it. Over a period the Nitrogen leaks out so you have no stored pressure, hence the pump has to cut in to raise the pressure as soon as you use the brakes. You can't turn those lights off with the Nanocom, or, if you can, they will come straight back as soon as you use the brakes again.

My point about the EDC licence is that you've got a licence for your engine type and a second one for the other P38 subsystems but it will only show systems that you actually have. Hence no mention of Wabco D if you have a GEMS licence as the GEMS never had the D system, but as the diesel is the same licence for all years it gives you the option of either depending on the year of the car. However, the ABS document from BBS tells you which you will have from the year of the car.

It certainly sounds like you have an iffy connection to one of the sensors. They have plugs that should be held in clips on the chassis, but they are a bit of a bugger to get to as they are behind the inner wheelarch liner. If anyone has ever been in there before it is quite possible they didn't put them back into the clips so the cable could have chaffed against something. Sounds like you've got similar weather to here, far too cold to be outside laying on the ground under the car. I've got an ABS Fault/Traction Failure error on the Ascot but just ignore it for the moment. The brakes work, it's only the ABS and traction control that won't.

Answering your question on the dark side, on the BBS website there is a separate document for each system with what readings you should expect to see. EDC (diesel) is a bit odd as there is only the one entry. With a Nanocom licensed for a V8, if you have a GEMS licence, the only option you have for ABS is Wabco C as all GEMS cars used the C system, while a unit licensed for Motronic (Thor) will only show you the Wabco D option, you'd never see both and have to choose which one.

Wabco C up to 1998 model, Wabco D from 1999 onwards. Go into that and the top button is marked Faults, tap that and Read Faults, read what it is, then tap Clear Faults. If it comes straight back, then it is permanent. Beware though, the Nanocom ABS function can get it's left and right mixed up so if it says left sensor open circuit (or left sensor short to ground) it may actually be the right sensor.

That would also explain why people have said the ride improves with new air springs. New ones will have nice supple rubber compared with older ones where the rubber has started to harden with age so will flex less. Same with the Arnotts which, from the one time I have ever seen them, they appear to be thinner so will flex more, giving a softer ride when extended.

Now that is what I thought, the ride gets firmer the lower the height, although others seem to think it is the other way round?

Mine, with the 2 pin sensor, also reads differently to how I would expect it to. It has always sat very slightly above vertical, suggesting the temperature is higher than the Nanocom (and two other generic OBD readers) tell me it actually is. My sensor died so I kept the Nano plugged in to keep an eye on the temperature only to find that it runs very cool, around 85 degrees C. As they are no longer available, I got a second hand one from a breaker and fitted that. Initially it read below the centre point, exactly where I would expect it to be with the lower running temperature. Over a period though it has crept up and now sits where it always used to, very slightly higher than vertical. On a long downhill when the temperature would drop, it does, but under normal running, it stays just above what would be considered as normal despite the actual temperature being below normal. Considering the analogue voltage from the sensor doesn't drive the gauge directly, but reports to the BeCM which sends a data stream to the instrument cluster which then converts it back to an analogue signal to drive the gauge, I suspect there is some sort of adjustment going on so the gauge reads normal irrespective of actual running temperature.

It isn't often I sit and ponder why something works the way it does, I tend to concern myself with how it works and how to fix it when it doesn't, but this exchange had me intrigued so I've just been doing some sums out of interest.

Unladen weight on the rear axle with the car at kerb weight, is around a tonne (varying slightly depending on whether, petrol or diesel, manual or auto), so, as we normally measure pressure in pounds per square inch, we know the number of pounds. Without actually measuring one, I'd estimate the interior diameter of a rear air spring as around 6 inches so to convert that to square inches we multiply by Pi, giving a cross sectional area of 18.85 square inches. 1 tonne is 2204 pounds, so assuming that would be equally spread from one side to the other, meaning 1102 pounds on 18.85 square inches, or 58.4 psi.

Maximum axle weight when fully loaded is 1840 kg, or 4056 pounds, so that would give 2028 pounds on 18.85 square inches, or 107.6 psi.

In neither case is the height relevant, it won't change no matter how high or low the suspension is, the weight and cross sectional area of the air spring will still be the same. It also explains why the system pressure switch operates at 140 psi to switch off the compressor. Unless the car is grossly overloaded, there will always be sufficient pressure available to deal with the weight. This also explains why my 5.6 bar (81 psi) tyre inflation compressor was only just capable of causing my suspension to lift. Doing the sums backwards means 81 psi would be capable of holding up 1530 pounds, ample if the car was completely empty but not enough to lift it had it been fully loaded. Considering my boot carries an LPG tank in addition to a spare wheel, my toolbox, 2 tonne trolley jack, the assorted spares that live in there and it also had 3 people and one persons luggage, I suspect the rear axle weight would have been pretty close to that so right on the limit of what the pump was capable of.

What I can't get my head around is the effect the piston on the bottom of the air spring has. I know that with conventional springs when talking about spring rate we talk about deflection with weight, X pounds weight on the spring causes it to compress by Y inches, but how is that going to change? With the suspension on High, it isn't inside the rubber bit so is having no effect but when lower it is encroaching into the chamber full of air. The cross sectional area, and hence pressure, won't change though, just the volume of air needed to fill the available space will be less. So how can that influence the spring rate?

My train of thought, and there is no way I would ever claim to have a full understanding of it, is that the springs are never going to be soft. Irrespective of the height the car is sitting at, the weight on each spring will be the same so it is volume of air in them rather than pressure. Agreed, it needs pressure to lift the car off the bumpstops but surely, once it is at the desired height, the pressure will be the same?

To keep the twin axle trailers I regularly tow level so the loading on each axle is the same, the suspension should be in Standard, but I've found that it feels much more stable if I'm in Motorway. I recently towed a single axle boat trailer with a boat that weighs 1,100 kg so probably around 1,800-1,900 kg total and it was very noticeable that it felt far more stable in Motorway than in Standard. I've no idea why or the mechanics of it, I'm just going on the feeling through the seat of my pants. Maybe it is just that I'm lowering the centre of gravity?

Chasman wrote:

Viewed in system terms it's actually very simple.

I've been saying that for years, it is once you get your head round how it works. I think the Invalid Fault Code may be a Nanocom thing, not sure if you get it with EASUnlock. The solenoid stuck shut faults are down to the way the fault messages have been written. It has no way of knowing if you have a leak, all it knows is it told a corner to rise, it didn't within the time it expects it to happen, so concludes the solenoid must be stuck shut. If whoever wrote the fault codes made it read 'RR Leaking' instead of 'RR solenoid stuck shut', it would be far more likely correct.

Not sure I agree with the other observations. The dampers merely damp the oscillations so are going to work the same irrespective of ride height, although I agree load will have an affect. It amuses me when people say the shocks are completely worn out as you can compress them and they stay compressed. They will, they aren't pressurised gas shocks so won't extend on their own, the test is how quickly you can compress them. As for spring rates being upside down, how do you come to that conclusion? I've always found it to be the other way round, the higher it is the softer it is. There was one road I used to use regularly where I'd turn off a nice smooth 60 mph stretch, so it would be at Motorway height, onto a pretty grim bit of potholed, bumpy, road. The bumps always felt far worse until I'd poked the inhibit and rocker to raise it up to Standard. For the same reason I always lock it in Motorway when towing (although the handbook says to lock in Standard), as it feels far more stable at that height. It's got something to do with the way the bottom of the rubber bladder wraps over on itself the lower it goes.

That's another way of doing it, especially if you trim the ends of the pipes. It always amuses me that RAVE, which was the official manual supplied to main dealers, suggests chamfering the ends of the pipes with a pencil sharpener and removing O rings with a crochet hook. Just what you'd expect to find in a mechanics toolbox......

It has been found to work in some cases, not sure why, possibly as the height sensor readings were so far out it gave up and did nothing, or just that the ECU wanted to see some sort of movement. You've nothing to lose by trying it.

Did you get my PM?

I've never disconnected the battery, just make sure ignition is off and the key is in your pocket. No power is no power no matter how you achieve it. Take the cassette out, tape it so it can't rotate and test for continuity from one end to the other.

Yes, all you've got is the BBC multiplex although no idea where from, the transmitter checkers don't show any transmitter sites north of Mounteagle, just north of Inverness, but that carries 3 multplexes.

1Steven wrote:

Can I pick up a 12v supply in the boot?

Yes, behind the LH rear light there's an unused 4 way connector put there for twin socket electrics. It has permanent live, ignition switched live, reverse light feed and ground in it.

Surprised you've got DAB reception in your area though.

As I understand it, and will admit I have had one that didn't seat properly so leaked, it is only the very thing ones that go on the top of the solenoid plunger. In the kit they are marked as Solenoid plunger seal and there are 7 of them. They are about the only ones that don't leak and the ones where you need to take to actual valve apart (two little Philips head screws), if you are concerned, then don't strip the valves to change them.

Checked my GEMS a few minutes ago. Fuel rail lost all pressure when I connected my pressure gauge, but turned the ignition on and it immediately jumped up to 40psi, started the engine and it dropped to 30psi but as soon as the engine started, stabilised at 35psi. Switched the engine off and it sat at 35psi for a good 15 minutes without dropping at all. So yours is definitely leaking somewhere.

As David says, the round thing on the input hose is to smooth out any surges in the fuel line. The pressure regulator is on the opposite side hiding behind the throttle linkage and excess pressure is fed back to the tank on the other hose. I'm assuming that if there is a one way valve, it will be inside the pump but if that had failed it would be a bit of a coincidence that it has decided to do it at the very same moment you have had the fuel rail off. You could try clamping the return hose and seeing if the pressure still drops, that would suggest the pressure regulator or a leak at the top of one of the injectors. The O rings can get pinched when you put the rail back on, but the leak should be obvious, you'll have fuel running out of the rail and flooding onto the top of the inlet manifold.