davew wrote:

PS: While you have the MOT Testers book handy what does it say (indicate) about chassis corrosion on P38s ?

I don't have it handy, I just open it up if I need to check something, it's here https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles

Your note isn't a specific fault but a free text one put in by the tester because he can, so anything that doesn't have the exact section number is a pedantic tester (usually done so gullible customers will pay him to put right faults that aren't actually faults). I've seen ones like, "Sump rusty but not leaking" and? The section on the chassis is https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/6-body-structure-and-attachments and the appendix (https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/appendix-a-structural-integrity-and-corrosion) points out to thick testers what bits he should look.

Bolt wrote:

Section b seems to be referring to "components" that may have been modified.
If the whole suspension has been changed, it would not apply.
(Oh my, what if you modify a spring!?)

I think you are probably right as the whole system has been changed, so it is the vehicle that has been modified, rather than an individual component. I've seen a car (not a P38) that had had the suspension lowered by clamping the springs and heating them up with a welding torch. That, I would assume, would be noticed by the tester (I noticed it as soon as I looked under the car) and frowned upon but if whoever did it had simply cut one turn off the coil, as long as it remained in place when the suspension was fully extended, it would be no different to fitting a shorter spring.

What's it have to say about "modified vehicles"
Surely changing the whole design of the suspension would qualify as a modification?

There's only the odd mention of modified vehicles, for instance, if a car has been fitted with an engine older than the car, the emissions limits are those that apply to the engine as limits have been tightened over the years. So if I was to ever achieve one of my fantasies of fitting a P38 V8 into a Prius, the emissions limits would be for the P38 engine, not those that would apply to the Prius. Most modifications are allowed here as long as items still work as expected. I know of one car that is virtually all hand built using a pair of 6 cylinder Jaguar XK engines in tandem so it is an 8 litre straight 12. That was built on the chassis from an old FX taxi (the traditional London black cab) and, as it retained the chassis and suspension from the original vehicle, it is regarded as the same car.

The only reason I was looking was because I wanted clarification on whether a spit ball joint boot on my other half's Merc would be a fail or advisory. Seems that a boot that is deteriorated but still keeps dirt out of the ball joint is an advisory but if it is split and would allow dirt in, it's a fail. Which is a real bugger as I've got to change a track control arm and re-align the steering because the boot is split and not because there is any wear in the ball joint......

Surely under (b) the suspension system has been modified? That is how I would read it anyway.

While looking something else up on the MoT testers manual, I came across this section

5.3.5. Gas, air and fluid suspension

Defect Category

(a) A gas, air or fluid suspension system inoperative - Dangerous

(b) A gas, air or fluid suspension system component damaged, modified or deteriorated in a way that:
(i) it would adversely affect the functioning of the system - Major
(ii) its function is seriously affected - Dangerous

(c) An obvious leak from any part of the system - Major

That suggests to me that a P38 on coil springs should be an automatic fail under 5.3.5 (b)(i)

You won't get an error as the ECU doesn't know the difference between failed sensors giving 5V or a lean mixture giving 5V. Don't forget that GEMS is only just OBD compliant as it became mandatory from 1994 in the US market, it only changed when OBD2 was required from 2000 onwards (hence the change to Bosch Motronic).

PaulD4 wrote:

So now I know the LHS motor should run low speed as soon as there's an AC Request HVAC to GEMs,

No, they should both run low speed when there is an AC grant from the GEMS ECU.

and the RHS motor should run low speed too if the X315 switch goes over 21 Bar,

No, the RHS should run at low speed in series with the LHS fan. If the X815 switch goes over 21 bar, then both relays 13 and 14 operate and they both run at high speed.

If I drive the fans from the Output Options on Nanocom both fans run at low speed - not sure why both run

They should, they are in series. You need to check if relay 18 is operating and that is controlled by the GEMS ECU.

To be quite honest, when running at low speed they do naff all so I wouldn't worry too much about them not running then. It is only important that they run at high speed when needed.

They aren't controlled by the HEVAC, but by the engine ECU. The diagram isn't the clearest but they should run at low speed whenever the engine ECU sends a AC grant signal (which it should unless it is getting too hot). Power comes from fuse 31 and goes directly to the LH fan motor. The other side of the motor goes to centre contact on changeover relay 13 which is not operated unless the AC refrigerant pressure exceeds 21 bar (which it won't unless the AC is having to work really hard). From the normally closed contact at relay 13, it goes to the contact in relay 18 which should be closed by the AC grant signal from the ECU. The other side of that relay contact goes to the normally closed contact in relay 14, another changeover relay that operates in parallel with relay 13, and from there to one side of the RH fan motor with the other side grounded so the two fans operate in series so at low speed.

If the AC refrigerant pressure exceeds 21 bar, both relays 13 and 14 are operated so the connection from the LH fan goes via the relay contact in relay 13 directly to ground and power from fuse 36 goes via the now closed contact in relay 14 to the RH fan motor so they both run at high speed.

Are you sure both run at high speed? I noticed that mine didn't seem to run at low speed and that was down to one of the fan motors having burnt out so it was open circuit. Like that they won't run at low speed but the remaining one will run at high speed.

The O2 sensors shouldn't read a constant voltage, they should flip flop between 5V and 0V about once a second. 5V means it is running lean so the ECU will put more and more fuel in to richen the mixture until they read 0V. If they stay reading around 5V, they are dead so never will drop to a lower voltage.

Marty has a lot of work with the day job, so may take a few days to reply. He sent me a filter and key fob for the red car and postage from NZ to UK took 6 days.

Head gaskets, plural, suggests a V8 so your D2 will have the Thor as fitted to a similar age P38. Take the serpentine belt off and try spinning all the idlers, the PS pump, alternator and water pump. I've known a water pump to squeal but only on initial start up not all the time and the alternator is also suspect. Any roughness should be felt and that might be a better way of identifying it that listening for it.

Like this https://rangerovers.pub/topic/152-dodgy-main-beam-headlight-flasher-stalk-modification?page=1#pid18390. The white nylon part wears away with putting the indicators on so instead of having a gentle curve to it that the lever bears against, it wears flat.

The dash switch bulbs are stupidly expensive but are just a plastic housing with a wire ended bulb. The bulbs can be bought from CPC (https://cpc.farnell.com/sli-ebt/7219-004/wire-ended-3mm-12v-1-9-lumens/dp/SC00339) at under £4 for a pack of 5 or Mouser (https://www.mouser.co.uk/ProductDetail/606-CM7219) at roughly the same price but sold singly. All you need do is unwrap the wire on the original bulb from the housing and pull it out, carefully remove the coloured cover, fit that to the new bulb and fit it into the holder, wrap the wire around and then then snip off the excess wire. The only one that is different is the one for the Hazard light switch as it doesn't have the coloured 'condom' on it, just plain white.

Simon beat me to it. The fact that you've got an intermittent rough running and fuel in the oil, it might be that you have a fuel injector sometimes sticking open. That will bucket fuel into one cylinder so it runs ridiculously rich, lambda sensor will detect that and lean off the mixture. So you will have 1 cylinder on one bank still running rich while the other 3 will be running lean. Pull the spark plugs and look for one that is black to see if you can identify which one it might be.

The cylinder thing where the fuel pipe joins the fuel rail, is there to smooth out the fuel flow rather than have it arriving in pulses.

It is a pump and bladder. On non-memory seats the supply from fuse 10 goes directly to the lumbar pump but on a car with memory seats it goes to the seat outstation.

nigelbb wrote:

AFAIK no P38 seat has an inflatable lumbar support.

Yes they do, all of them with memory seats and possibly those with electric non-memory too.....

From the owners handbook

That's confirmed it. After a couple of days sitting outside at -2 degrees, just checked both iffy latches again. Using the tests as shown in that video, both still operate the keyswitch when the lever is moved but one was intermittent and the other only operated when the lever was right at the very end of the travel. So cold weather and a tiny bit of slack in the connection to the rod is enough for the keyswitch to not operate reliably.

That sounds a lot. Tax on a pre-2001 P38 is only £30 a month and I'm paying just under a grand a year for unlimited mileage, unlimited number of cars, maximum value on each £10k, traders policy. As long as they see a bit of turnover they are happy. A couple of years ago insurers got very twitchy about Range Rovers due to the number of the newer ones being stolen, although when I explained that although I had 2 listed on my policy they were older ones that aren't at risk of being stolen. Last year they were only loading anything later than 2010.

If you are going for limited mileage, then a Classic policy might be an option.

Mina says that every time I turn the ignition on and has done for about 8 or 9 years, only on mine it says FUSE 20 FAILED. Fuse 20 hasn't failed and as it supplies power to the passenger electric seat I don't have, I just ignore it. Apparently there's a resistor on the BeCM power board that is part of the fuse checking circuit and it sometimes fails. I've got a spare BeCM power board that would cure it but have never got around to fitting it. I've got so used to it, if I don't get the Beep when I first turn the ignition on, I'll probably think something is wrong......

I've got one that I took out of the red car when I fitted the LPG tank. It's yours if you want it.

Whereabouts? I'm just outside Peterborough (Stilton) and my Nanocom has licences for all 3 variants of P38.

Rural locations can be worse. My day job used to involve going out and finding the sources of interference and common ones in rural areas were remote weather station senders and oil tank level senders. Others were wireless burglar alarm sensors and wireless central heating controllers. Both the former will make a transmission every 10-15 minutes so can keep waking the BeCM.

RF interference will flatten the battery but won't affect anything else. Admittedly if the battery goes completely flat, than can result in it being immobilised when recharged but as long as the microswitches in the latch are good, all you need do is enter the EKA. It won't damage the BeCM by keeping it powered, it is powered all the time the ignition is on anyway.