I've heard rumours that this can be caused by a failing BeCM but, as you say, if that was the case cycling the ignition switch wouldn't cure it. If the BeCM has been drowned somehow, a high resistance ground on the ignition switch input could cause it, not been wading by any chance? Other than that, it could be a broken ignition switch so there is something that has broken off and is floating around inside the switch.
If you unplug C257 from the BeCM and it still does it, then it is looking towards the BeCM, if not, the switch.
I've got the plastic bits but no dog guard, presumably from when plod owned it, and the metal plates must be templates as they aren't there. You wil need the rivnuts though. If the bolts are M8, then an eBay search for M8 Rivnuts comes up with plenty of people that will sell you the nuts but you'll also need to buy the tool to insert them. Alternatively unless you have a very strong dog, these https://www.ebay.co.uk/itm/372228875618 should be good enough and don't need a tool to fit them, just a bolt and washer.
It does, Nigel has found he does a couple of miles to the gallon less than on petrol but with the price difference it's still far cheaper. With LPG, and most other fuels in France, being the most expensive in Europe, it'll be even cheaper for me to run on it over there and LPG everywhere else.
As for running on veg oil, I noticed when the petrol and diesel shortage was happening a few weeks ago, my local Tesco had empty shelves where they would normally have the 3L containers of cooking oil.
That's right, 0.69 Euros a litre for E85 in France compared with 0.99 a litre for LPG (most expensive in Europe) and over 1.60 for petrol and diesel. Now I've sorted the heater circuit error on one of my lambda sensors so one bank always ran open loop on petrol, I'll be running on E85 whenever I'm over there. Seems that although the V8 P38 isn't listed as being flex fuel, it runs quite happily on it.
and people are getting their knickers in a twist over 10% Ethanol......
2 pin are cheaper if you need to replace them...... Mine has the 2 pin in it and has towed very heavy trailers up and down the side of a mountain a number of times and never given any trouble. The original whined like a London bus after around 250k miles (and gave a very healthy clunk when going from Drive to Reverse) so I treated it to a refurb from Ashcrofts and have had no more problems. My front has recently started to whine slightly at neutral throttle (silent when under load in either direction) but i suspect I'm the only person that would notice it. The Ascot, my spare, being a 4.6, should have the 4 pin (although being a 96 may not) and that has a weird speed related drone all the time. No difference under or off load or when turning and loading one wheel bearing more than the other, so I need to investigate that but I don't think it is the diff.
I think the 4.0 litre and diesel had a 2 pin diff while the later 4.6 got the 4 pin.
Nigel's car was treated to a new radiator, heater matrix and thermostat, along with the entire cooling system being back flushed, so the cooling system was virtually drained completely and put up a real fight when I tried to refill and bleed all the air out. Not sure if all Thor motors are like this or not but I've never had any problem bleeding air out on a GEMS. One thing I noticed on the Thor is that the hoses to the heater have a hump in them, so even those are a potential air lock waiting for some air. At least it's working properly now though.
Did you put the washers on the mounting posts the right way up? Bottom ones have concave face down while the top ones have the concave face up.
I'm currently rebuilding a 4.3 Mercruiser boat engine, a V6 that is a marinised version of 3/4 of the 5.7 V8 small block Chevy engine. If you think some of the design features on a P38 are bad, you want to try working on one of those......
The sensor is on the lower of the two aluminium pipes that go to the heater matrix next to where the O rings live. It isn't unknown for the connection to fail so unplugging it and giving a squirt of contact cleaner is often all it needs.
I'll be completely honest, having seen the bottom ripped off a brand new radiator because the holes didn't line up so it was under tension, I've never refitted them. The rad is held in place at the bottom by the pegs and rubber bushes, at the top by the slotty things and gravity. Even if you managed to turn the car upside down, I doubt it would fall out (although the security of the radiator would probably be the least of your worries if the car is upside down).
No, there's no gasket between axle and hub, they just go together dry. Never known them to leak from there either so obviously don't need one. Thinking about it, there's the oil seal in the axle and the wheel bearings are sealed so there shouldn't be anything in there to leak out in the first place.
I've considered taking a mould off a backplate and making some up in fibreglass, problem is finding a backplate good enough to take a mould from (and no, I'm not spending in excess of 100 notes for one to use).
Certainly looks a bit on the crusty side but at least it isn't leaking oil so is only on the surface. Of course now you've caused yourself more problems when it comes to separating the axle from the trailing arm as it is no longer secure so you could end up chasing it around the garage. Hub bolts usually come out easily enough as long as you can get a good grip on them with a socket. I've got a set of these https://www.machinemart.co.uk/p/5-piece-bolt-grip-set-expansion-set/ and the 13mm one is almost worn out now. The more grunt you put on them, the tighter they bite.
Tell you what though, your disc protector backplates are better than mine. One of mine has come free from one fixing and is flapping about so clanks every time I go over a bump. I'll need to change the rear pads in the not too distant so I'll deal with that then.
Crossovers should be passive so no power there. DSP amp completely removed so how come the speakers are producing a whine? Is it possible that the output stage of the head unit is permanently on even when it appears to be switched off? You could try completely disconnecting the power to the head unit, both permanent and ignition switched and see what affect that has.
There must be an amp that is still powered in there somewhere. You say the amp is bypassed, is this the DSP amp in the boot or the 4 individual door amps? There is a turn on signal from the head unit that causes the amps to be switched on (there have a permanent supply but stay off until a signal is seen on the turn on line). On an aftermarket install, but still using the amps, that would be connected to the electric aerial line. If you aren't using the amps, then there is no need to power them. They can't be fully bypassed or they wouldn't be connected to the speakers. It all depends on what you have and how it has been wired.
Hmm, just realised. 10 stone plus a 5 foot bar equals 700 ft/lb, no wonder there's been nothing I haven't been able to get undone. Bouncing up and down on the bar means I've probably been able to achieve 1000 ft/lbs!
The most important bit, and often overlooked, on the back end, is the Panhard Rod bushes. If there is slop in them they allow the axle to move from side to side resulting in some very odd handling characteristics. I've never taken rear trailing arms off but have swapped a rear axle. The two bolts holding the axle to the trailing arm were a little on the tight side but a socket with my 5 foot bar on the end (an old front track rod bar) and putting my feeble 10 stone weight on it shifted them. If I remember right, the rearmost bolt was a bit tight to get a socket on due to other stuff (calliper carrier mounting?). This was an axle with a noisy diff, leaks from both oil seals and an oil leak from the weld on the diff housing so swapping the whole lot from a breaker was the cheapest and quickest solution. Especially when the rear discs were in a far better state than the ones on the original axle. However, having seen the pictures of the amount of rust you have on the underside of your car, I appreciate you might have more of a problem......
Just had a look under the Ascot. It appears to have had a sidestep on the passenger side at some time in the past and the brackets are still there. Not only are they there but are far better than any that I've seen pictures of. Rear one has obviously been clouted against something but if they were in the same state as the others pictured, would have just crumbled away. They're yours if you want them Chris.
The Ascot has obviously had side steps on it at some point in its life, or at least on one side anyway, as the brackets are still there. I'll have a look at it later this week to see if they can be got off without resorting to the angle grinder.