I figure its better making a new thread about this, rather than adding to the other post, as i'm fairly sure its a new/seperate issue...

As per this thread:
https://rangerovers.pub/topic/853?page=2

The car had weird fuelling issues before its MOT. It failed the test with massively high CO, then after being parked for a few weeks, would barely run at all with massive missfiring and belching out black smoke. Plugs were all caked black with soot when i removed them. There was a fault code which pointed to the MAF, so i got one from ebay, fitted it along with some new plugs and it passed the MOT just fine with perfect CO readings.

Fast forward to last night. Its not been used since it passed the MOT as it wasnt taxed, but i taxed it yesterday and took it out for a run to get pizza. Drove perfectly well all the way there and all the way home. It wasnt hugely far, maybe 4 or 5miles but enough to get it fully warmed up etc. Even gave it a full throttle blast upto 60mph and it was all fine. Until i turned into my street, when all of a sudden it wouldnt rev. Idled fine as did very light throttle, so i trundled into the drive and parked up.

Some cursory checking last night showed it was exactly the same on both petrol and LPG, and missfired both under load and while revving in neutral, at the same point on the revs. It would rev upto about 1500rpm, any more and it starts acting up. I tried it with the MAF unplugged, exactly the same. MAF readings also looked sensible enough. Lambdas also looked sane. I reset adaptions and no change. Checked CTS and it read fine.

Left it overnight, went out this afternoon and fired it up from cold, problem gone. reset adaptions and put everything back together and took it out for another drive. Sure enough, after about 10minutes, same shit. Managed to drive it home with light throttle. I dont think its load related specifically, but obviously being an automatic the rpms naturally want to climb up past 1500rpm and thus it starts spluttering.

I made a short video, i thaught the audio would have been much more audiable but its not that great annoyingly. Hopefully if you crank the volume right up you can hear it. However you can see me blip the throttle a few times at the start and it revs cleanly, then slowly adding throttle up to 1500rpm and you hear it start its weirdness, then i really opened the throttle and it started popping and banging.

https://www.dropbox.com/s/vu2ivbphj76cv0c/2018-05-02%2015.46.32.mp4?dl=0

I had a similar problem with my jeep. What is the idle like when hot? If it's rough, try disconnecting the petrol injectors (from the wiring loom, not the fuel rail :) ) one at a time while running on LPG. You might find one of the cylinders is getting both fuels and misfiring due to a very rich mixture.

It idles perfectly normally and revs fine if you keep it below 1500rpm, the problem happens on both petrol and LPG, my gut feeling is i dont think its fuelling related.

I'm wondering if its a crank sensor issue? Or something ignitiony

Yes an iffy crank sensor can do that !

+1 on crank sensor. Try dumping cold water on it when it starts playing up and see if that makes any difference. When they are failing, dying when hot is the first sign.

I’d go for either the CPS or TPS, when my TPS failed it gave a misfire

I had all sorts of weirdass behaviour after redoing my cylinder heads. Turned out that the crank position sensor plug was full of water.

The main symptoms were that it would rev perfectly okay to about 2000rpm, and then start farting and spluttering and backfiring. Dried the plug off, stuck it back in, fault gone.

I could easily see Aragorn's fault being a dying crank position sensor, especially since Citroën CXes with AEI do exactly the same thing :-)

thanks guys, ordered a bearmach sensor from LRDirect which claims to be OEM so will give that a go.

Oddly enough, this car seems to have a history with crank sensors. When i bought it, it was sold as a non runner, and the guy said the crank sensor was broken, and it would run for about 10-15mins then die. He said his garage had diagnosed the sensor had become contaminated with oil and the only way to fix it properly was to replace the rear main seal. Reading between the lines i figured he'd already changed the sensor, and it had broken again after a short period of time, and i figured it might have just been a crappy britpart sensor he used...

So the first thing i did was bought and fitted a new crank sensor. Sure enough when i removed the old one, i could see it was obviously not that old... It also wasnt that oily despite the leaking rear seal leading me to suspect his oil contamination theory was bunk too... However that didnt actually fix the problem, which instead turned out to be a faulty MAF.

So the sensor in there is only a year old, but was also a cheapy from ebay, so its entirely possible these cheap ass sensors are simply junk. Fingers crossed this bearmach one is better, or i'll have to stump up the £100 for a genuine one.

Don't bother with a cheap TPS - they don't work either :) Well, the one I put on my Thor certainly didn't.

Yeh, the TPS is a bit more annoying as those seem to be dealer only for £100, maybe better of trying to find someone breaking a GEMS engine and getting a used one...

This forum really needs a "for sale" and "wanted" section!

I replaced my CKP/CPS with one also designed for a mini/metro/maestro = ADU7340 = for about £20... and (..wait for it..) Made In England !!

EDIT: From a quick check on e-bay there are LUCAS equivalents SEB100 for about £25-30 too (but/and of unspecified origin...)

Incidentally I don't know quite why these go out of spec. either (as it's basically just a coil around a core/pin). The distance to the flywheel pins is
critical ( but unlikely to change unless damaged) so perhaps the magnetic properties change over time/heat (cycles) etc ?

As it is one of the few things that can stop a car dead in it's tracks, I replaced mine when the rebuilt engine went in about 60,000 miles ago. The old one was still working fine and I keep it in the boot just in case. The one I got was a Lucas too but from Island 4x4. However, there are 3 different ones, up to '97 (early GEMS), '98 (later GEMS) and from '99 onwards (Thor). The early one and the Thor one both have a flying lead with a plug on the end whereas the later GEMS just has a socket on the sensor itself. No idea which option the BL Mini, Metro, etc uses.

Fair point - I should have mentioned I was suggesting the (flying lead) ADU734O/SEB100 variant for Aragorn's '94 GEMS....

As many will be aware the LUCAS/TRW buyout was really just the name and their stuff comes from (very) afar now due to 'global
manufacturing trends'........http://www.lucaselectrical.co.uk/lucas-history.html

Have to admit I assume almost all 'mass manufacturing' of automotive components is 'elsewhere' these days....
but I also assume virtually all 'genuine'/OEM stuff on e-bay actually isn't either...

Thanks to Dave for posting that the CPS is similar to that used on a Mini. For the last few weeks I've been helping a mate who's wife has a P reg Mini as a weekend toy. It hasn't been running right for a while but it was mainly a hesitation when you opened the throttle and it seemed to get worse as it got hot. It's one of the later ones with MEMS single point fuel injection and everyone was blaming that. It had been running OK until there was a leak from the throttle body heater so that was bypassed but as it also houses the coolant temperature sensor for the injection the thermostat housing was drilled and tapped and the sensor moved to there. As it got worse when hot, we concluded this was the problem and it wasn't detecting that it was hot. Testing the sender resistance hot and cold showed that was OK, as was the wiring to the ECU. There's naff all information on the injected Mini about but I found a forum thread where vacuum leaks were being blamed for rough running. Checked those and found one had melted into two on the exhaust and others had split ends. Ordered a complete set, fitted them and while the idle was nice and smooth and with a meter on the lambda sensor we could see it responding correctly as soon as the throttle was opened, lambda went fully rich and it still ran like a dog. The more we touched it the worse it seemed to get, even taking the air filter off and putting it back on made it even worse. This was starting to make no sense at all.

Then Dave posted about using a Mini CPS and I started to think. This thing was showing the exact same symptoms as a P38 does when it is failing but it hadn't even occurred to me that it would have one. Checked and found it hides underneath the starter motor so phoned my mate last night. An hour later he sent me a picture of a CPS with a bent tip and a liberal coating of metal filings. Looks like we've found the problem. having had everything from the inlet manifold outwards off, stripped, cleaned, made sure there's no air leaks, new vacuum pipes, new fuel filter, checked the fuel rail pressure and even tried a new ignition coil, it was nothing to do with any of them. Once MiniSpares deliver a new CPS it should go like the clappers! As long as the reluctor ring hasn't been damaged that is.

Happy to help Gilbertd: hope it is/was the CPS (-it sounds like it). No doubt the mini does not throw up a Fault Code for it either. just like on our P38s....
Reluctor Ring pins are steel and should be (relatively) OK .... That said I know the CPS core/pin is just a few tho. away from those pins but I don't know what makes them actually touch together either (unless when really hot...?)

Finally got it swapped out on sunday. Not driven properly far in it, but had a few journeys and no recurrence of the issue thus far.

Old sensor looked totally fine, and the new one was identical right down to the markings on it, so despite the "OEM" claims of this new one, clearly it wasnt...