What fuel pressure do you see at start up? Those Laser spark plugs lights are a quick and easy way to get comfortable on the spark, may be worth pulling some plugs to see what you can see.
Is your idle air setup looking OK?

Sounds like you shd do the decent thing, old shep, and buy it back

Mad-as, Thanks for having the patience to got through the whole thing. I'm trying to work through things using data as much as possible, without changing parts at random. So the only thing that's changed on the air side is IACV steps - everything else passed muster (with the exception of the IAT sensor, but perhaps that's due to wiring resistance). Once the new 02 sensors (exhaust needed changing, and old sensors were rusted in) settled I haven't needed to worry about them. As you say, then there's fuel - the fuel filter's held me up for a few weeks now, the restart issue's not bad enough for me to have gone nuclear on the fuel filter, mainly cos I don't want to lose the fuel line if i don't have to, and the fuel pump is last on my list because it falls into PITA-to-fix territory, relative to the others, at least. Sooner or later I'll declare war on the fuel filter - probably when I next get close to E - and I think I'll do another pressure test on the fuel rail as I know the data sounds low (although the GEMS data for rail pressure and FPR pressure seems hard to validate definitively) - but i really don't have any power issues with the engine. It sounds better now than it has ever done - although still probably runs rich, and hence I opted to Redex the injectors, in case they were dirty. I've had the car a year and a half now, and so don't know how it sounded/felt 10 yrs ago, but I do have the 4.0L V8 in my Defender to go by and it compares quite well (but richer as noted). Sadly I don't have a boat to tow over hills :o)

If you fancy heading to Twickenham, I'll be happy to and I'm around most of next week, although Gilbert D taught me all I know, so he is the last word in P38s :o)

It's not impossible that there's some obstruction, and I still haven't managed to get the fuel filter off, that would tell me a lot about the state of the fuel system I suspect. I froze the filter/ fuel pipe coupling, that didn't work, and next I have some flare spanner-like vise grips coming. Unfortunately the whole connection is too narrow for me to get a crows foot on otherwise it could have been a quick job - but thus far I am in no hurry to strong arm it and end up ripping the end off the filter cannister. In the background I stuck some Redex in the tank today in the hope that that might help clean the injectors, rather than strip things down.

I have compressed air, is there a procedure for clearing the fuel lines/ rail ? or just blow....return to the rear, and feed toward the rail...

Ok, another difficult restart this evening. Car had been left about 10 mins. In that time the fuel rail temp was up to 70 degrees C. Presumably there 's an increase in pressure at this point too, but the fuel pressure regulator won't release until it has a vacuum ie engine running ? (I'm postulating, feel free to cry "bull s***" ). I need to find a way to keep my fuel rail a bit cooler when it's just sitting on a warm engine... It's dusted with black paint at the moment (though it's been there a while) getting rid of that might help a tiny bit, perhaps?

Ditto that - the Nano EKA unlock works on a 1998 too (goes by BECM version). It also means that even if your door lock does work ok,then you don't have to frag the lock by repeating countless eka sequences until you get it right :o)

I don't have experience of the others, but the Nano I have is pretty good. The documentation that goes with could be better, but after a while it will become second nature. I just pray my OBD port never packs up. It's not cheap, but given the number of issues that come up on aged P38s, will pay back eventually.

Harv, if you spent 45 years driving an S2A then I'm not surprised you love the P38 so much :o)

My 98 (ie WA chassis) has an "ANR 2239" modulator fitted, if that helps.

Good news !! With apologies to my PO, this may be more of a salutary tale of Lucas quality. I'd spared you this bit, but the replacement Lucas ECT sensor (made in China) didn't clip up to the engine harness correctly (i think the blades may have been 1 or 2 mm too long, so the assembly couldn't quite clip shut). I drained the coolant today, ready to remove the Lucas replacement from the housing, or tried... turned out the plastic connector/ 19mm hex was just turning on top of the brass sensor which was nice and snug in the inlet manifold. I obviously misinterpreted the slipping of plastic on brass to be brass on aluminium.
Now, maybe i tightened it a bit too hard, but since the manufacturer didn't care too much about making the connector fit correctly I reckon it was just poor quality period. Reading up on the Lucas company history they seem to have simply been sucked up into the ZF business empire and the name is licensed out. Maybe the Lucas box even guarantees it's a chinese knock off, as it looks like only lighting was licensed - or maybe I'm just the last person here to have worked this out :o)

Thanks for the extra option Clive. The time serts sound good, but I guess for the price I would then just buy a second hand inlet manifold, which is always an option as they're only 30-40 pounds. I think I'll just strip mine down and helicoil it, I was being lazy :o)

Ok, I've got an M12 x 1.5mm helicoil kit on order. Do you think i'm going to need to take the whole inlet manifold off etc to do this, or does someone have a clever idea for collecting the swarf and tang without it dropping into the water gallery?
I should probably be able to get the tang off with a pair of long nose tweezers, since this is M12, and recover most of the swarth using a bit of grease to cut with the tap. Where would these bits of swarth end up - bottom of the radiator?
Still, if i need to strip it down, it could be worse, and I'll test my fuel injectors at the same time

When I came to switching the ECT sensor on my 98 GEMS, it turns out that my PO stripped the seat of the sensor and glued it into place with something hard/ yellow. I'm guessing it was an epoxy glue. The question now is what's my best option to reseat it. Is it helicoilable? Or should I go the way of the PO and glue it into place? If so, what's the best glue/ to use?

I was at the tip the other day, and had the same restart problem. Then I got to thinking that the last two times i'd been to the tip I had the same thing...so it's obviously not the fact that I'm at the tip - but the fact that I've run the car under full load to get there, turned it off for maybe a couple of minutes as I've chucked stuff in the skip, and then attempted a restart. Could the fuel rail super-heat in that time? Or is that not a "thing " in a P38?
Still haven't managed to get my old fuel filter off yet, but I'm hoping that will get me a few more psi of fuel pressure.

As you said Richard. Open and zero stft at Ignition II, and then climbs fairly rapidly after start up to 38.75%. So I'll look elsewhere for a fix.

Thanks Mace, good to know I can eliminate the O2 sensors from the investigation.

Thanks Gents.

I'm SW London

Re injectors, I did a resistance test on them. and they all read consistently, but slightly higher than the range given in RAVE. I didn't write it down at the time, but RAVE talks about 13.3k +/-1.3k - i think they all came in at 16k, I took consistency to be a good thing, but since I didn't really get the significance of the resistance test left it at that. At the time i hadn't heard of any of the techniques of blasting the injectors etc, so have never physically tested for leaks.

I haven't used an oscilloscope since school :o) wiil it tell me anything that nano doesn't?I can see the switching on nano - seems fairly regular now, voltages 0-5v, and generating s.t trims of +/- 10%, but usually +/-5%. For the first few trips on new sensors they were giving rise to some wild ST trims, but ok now.

Thanks for looking into the 39% Richard, my neighbours must hate me - I just finished fitting a new alternator to the wife's Audi. I wonder if the 39% is a default strategy, but then if it is, why...what does it think has failed to execute that. It's a very specific 38.75% - same on both banks @ start

So using the "IACV percentage" value on Nano I reset the steps to c. 23 at warm idle. Still no improvement on the warm starts though. When it fails a warm start I reach for the Nano and write the IACV value up to 30 or so, from the zero or so it read prior to start-up. No idea if I should be trusting a pre start-up value, but it reluctantly comes to life that way - I guess conversely I could write a lower fuel setting.
Starting to think of just replacing the IACV and TPS just to eliminate them, and maybe the ECT sensor. Is there anyone/ anything that can dig further into the ECM than Nano - to try and work out what fuelling schedule it's using/ why? Currently it will do short term fuel trim 39% on any start, it looks like. For a cold start that's fine, but for a warm start that doesn't work.
I'm also planning to replace the fuel filter, which clearly hasn't been done for aeons (and so may get my fuel rail pressure up), since one union is frozen solid and clearly hasn't been touched in a while. I have a good 5/8" nut to grip on, and the fuel filter nut is good at 13/16". I have been dousing with WD 40 for a few days now, no joy. I haven't been able to get a flare spanner on the 5/8 end as there is not enough clearance to get one on, unless you use a 1970s bike spanner. So I haven't been able to get a crows foot on and try and rattle it free. I've banged/ tapped the spanners with a hammer, nada...
I really want to avoid the car going up in smoke (so not heating the union), and/or having to replace the filter to pump fuel pipe. Anyone got a funky way to release a rusty union of what I guess is stainless steel vs steel

:o) the in and out bit I had, but it never hurts to point out the obvious