Marshall8hp wrote:
In theory they shouldn’t run without a MAF. The engine should start, run up to 500 rpm and then stop.
With the (broken) MAF connected it starts and then immediately dies.
With the MAF unplugged, First turn it fires then stops, if you try again it cranks for ages and sort of half heartedly stumbles into life. Once it gets to idle speed it then runs and drives totally normally. On the road you actually wouldnt know at all that theres no MAF installed. It accellerates and drives as you would expect. Perhaps a little down on power if you floor it.
Did 20miles in it yesterday with no MAF, started and stopped it 2 or 3 times. Same thing every time.
The problem is that on that second attempt, you need to fettle the throttle just right. Not enough, or too much and it wont go. Which is what the missus ended up doing. I think it then ended up flooded.
I was in a meeting and said i'd be along in 30mins. In the mean time some mechanic stopped to help and managed to get it started with just the right amount of throttle.
Anyone here running a pattern MAF on their GEMS P38 and how do you find it?
My third used OEM one has failed, and while it runs pretty well without it, its a pig to start, which left the wife stranded on the schoolrun this morning.
I've ordered yet another used one from ebay, but clearly these are all old and failing.
Pattern units for other cars have a very poor record for actually working properly, so i've generally avoided buying a pattern one for this, but maybe its time to have a look?
Just after going thru 4 pattern crank sensors on this car, i'm super wary!
davew wrote:
Back (more) on topic just why exactly are LPGs vehicles on the decline if they are effectively 'greener' than diesel/petrol ? Surely they should be encouraged more ? Or do we all have to buy electric/H2 cars soon because the car manufacturers are lobbying for this ?
I suspect a big part of this is simply the faff. Aftermarket installs simply arent as clean and tidy as something OEM. And your carrying around two fuel tanks and are having to top up with petrol and LPG.
Modern diesels closed the cost gap entirely, and the majority of folk dont seem to actually care about green/environmental issues, especially if it adds any sort of inconvenience. Price wins out at the end of the day. Which is also why the government ends up needing to "force" the issue by banning things, rather than hoping people will do it themselves.
davew wrote:
Fair enough Richard, in fact the small battery/shorter range EVs are aimed mainly at city folk of course. It may be unfair but as I have explained to many folks the 'big battery' models weigh so much it is like having four passengers in the car all the time. Still surprises me how many are attracted to EVs because of the (perceived) Car Tax/VED savings....
"Smart" Meters are something of a con of course, I suspect they will introduce 'timed tariffs' at some point... and those without are already paying for their roll-out too...
Back (more) on topic just why exactly are LPGs vehicles on the decline if they are effectively 'greener' than diesel/petrol ? Surely they should be encouraged more ? Or do we all have to buy electric/H2 cars soon because the car manufacturers are lobbying for this ?
This is what the Mayor of London thinks anyway...
A Tesla Model 3 weighs the same as a current BMW 3 series... My LEAF weighs 1600kgs, a bit fatter than a modern Golf, but only by 100kgs or so. The Enyaq i've ordered is 2 tonnes, but its also the size of a P38, so not really surprising.
As for London, the main issue there is getting the tailpipe emissions out of the city centre. LPG doesnt help with that.
Gilbertd wrote:
I'm not going to get into this one as I'm one of the ones where range and charging time really would make an EV a non-starter for me, but I find it highly ironic that they are pushing everyone to get a smart meter installed so they can monitor their energy usage and modify their way of life to save a bit. Then they want everyone to buy an EV so you use far more than you are saving.....
You may well be one of the edge cases, but given your driving an LPG powered range rover, which can probably not do much more than 200miles per fill anyway, i suspect your stretching the reality a little. Ofcourse, if your doing a lot of towing for instance then you've got a perfectly valid arguement against them currently, as there arent a great deal of options for models that can tow. Its more about keeping an open mind!
One advantage of smart meters is it enables time of use metering. What the national grid dont want, is everyone driving home from work, plugging their car in at 6pm, when the grid is already under maximum load. By offering cheaper tarrifs at other times of day, you can encourage people to charge at a time when the grid is not stressed, like at 1am. The grid is perfectly capable of handling EV charging, just so long as the bulk of its not done during the evening peak!
Symes wrote:
Nobody seems to realise the environmental catastrophe caused by mining for the metals required for batteries for electric cars ---- I'll keep my disco and my collection At least I'm helping the environment that way
Well clearly they do, and work is going on all the time to improve all aspects of that process. For instance they're working to remove cobalt from battery chemistries all together. Furthermore its not like pulling the oil out the ground is all rainbows and butterflies either is it? You cant simply focus on lithium mines, say look thats shit, and ignore everything else. Well to wheel figures, when done properly show that an EV is significantly better than an ICEV over its lifetime.
One really nice thing about electrification, is that it centralises the emissions, which makes them much easier to control. Furthermore, it means vehicles will tend to get cleaner over time as the grid decarbonises, unlike ICE vehicles whose emissions deteriorate as they age, due to the various parts of the engine and emissions control systems wearing out, or dodgy modifications performed by their owners.
Its quite funny how people who havent actually ever tried an EV think charging is somehow really difficult and time consuming, and that filling up with hydrogen is somehow the fix. I guess the media is largely to blame, as i'm not sure where else they're getting these ideas from. The missing piece is that 99% of my EV charging doesnt actually happen with me stood there waiting on it. I plug it in at night, and it charges while i sleep and its full in the morning. Its also plugged in just now outside the office, and will be full again when i leave to go home. It simply doesnt need to charge in 5 minutes, because cars spend the vast majority of their time parked. In effect, "charging" takes the 10 seconds required to walk over to the wallbox, lift the cable and jam it into the socket. I dont have to drive to a filling station. I dont have to sit in a queue, and then stand there squeezing a lever (or pressing that damn button on the LPG pump!!) then go in and pay. Ofcourse, it CAN fully charge in 30mins on a suitable charger, but thats really the exception rather than the norm. I would never want to pay some filling station to fill up with hydrogen, when i can fill the car at home for a fraction of the cost. Why would anyone choose to do that? I really cant fathom it.
Plus, almost all of our hydrogen comes from natural gas. So i guess thats why its being pushed from various avenues, as it keeps those oil companies happy. But it also means its not actually "green" at all. and yes, you can produce it in other ways, but they're horribly inefficient.
Someone will always pop up with some edge case of wanting to drive 3700 miles in one day, but the reality is those really are edge cases. A 300mile EV has a range that fits quite nicely with when people should be taking rest stops anyway, and even a 200mile one, driven in the UK on our crappy congested roads, isnt really a huge inconvenience. My LEAF only manages 80ish, which i'll be the first to admit is pretty shite, but its plenty for my commute and a huge swathe of the UK population never drives anywhere near 80miles in a day.
If you can manage to drive across the country in an LPG powered range rover, then you've already proved the range afforded by many current EV models is sufficient.
Personally, i'd be taking the fan blades off rather than running it with smashed up blades. If the blades fail at high RPM it'll trash the radiator. If its out of balance you'll also ruin the bearings on the water pump in no time.
yeah shell dropping it seems to have had a big impact, there was at least 2 shells i routinely passed on the way to work which had it and now dont.
Usually, the P38 just gets used for odd trips, it usually has its place as the third car, so running on petrol probably wouldnt be the end of the world, however these last few months its been getting used a lot more as we've had a third child and two adults plus three kids simply dont fit in the A4 or LEAF. We've ordered a LEAF replacement but its delayed and so the P38's being used much more regularly. Futhermore, at that point its not the cost difference between petrol and LPG, but the cost difference between petrol and electric which is significantly more painful 🤣
As for the longer journeys, i must admit i like driving, but recently i've found that the joy is all sucked out of it as the driving standards are lower than i can ever remember, and the roads are all just rammed full of arseholes. Also, the P38's AC is broken, which hasnt been much fun these last few months!
Or its slipping badly and the ECU can see that and stops drive...
https://www.ashcroft-transmissions.co.uk/frequently-asked-questions/4hp22-faq-s.html
My Autobox is now only able to select reverse. Why?
Your A clutch (forward drive) has failed and you will require a replacment autobox.
Sounds like it could be a mechanical issue...
Have you actually checked the gearbox oil level and condition? I dont see it mentioned? Maybe start with a filter and fluid change?
Not sure if i'm imagining this or not, but is LPG getting harder to find these days? My usual home station (an Asda) and the Morrisons at my parents are still okay, but when out and about i'm finding they are somewhat rarer to come across. A few shells along various common routes i use have all dropped LPG. Theres literally none on my route home from work so if i run out away from home i have to drive home on petrol!
Tried a 7'x4' unbraked trailer today, loaded with logs. Towed smooth as silk, wouldnt even know it was there.
Even over the really rough bit of road after the Queensferry crossing that had the whole car jiggling with the big trailer, there was only the slightest of vibrations. None of the horrible banging and clattering the big trailer does either.
Will be picking it up again later in the week unloaded, so be interesting to see how that compares.
Gilbertd wrote:
Or if it isn't going to be linear you should be able to work out the curve from a Bosch one. This does assume you have one that is working so you can read the airflow and measure the voltage.
Yeah, my plan was just to connect them both up to the engine in series and log the output from both. Since we know the Bosch curve, we can plot the curve for the SAGEM unit. But ofcourse, that only gives you useful data if both MAF's are actually working correctly.
Bosch Motronic ECU's have a 512x1 lookup table which contains voltage against airflow. Its pretty easy to extract it if you have a good definition file for the ECU. The SAGEM must surely be the same, but there doesnt seem to be many folk that have put the effort in to these ECU's.
Its almost never linear unfortunately. They tend to design them with much more resolution at lower engine speeds. so the curve ends up exponential.
heres a few bosch curves for instance:
So i'd like to do the gaskets and i'd like some pointers.
I want to use quality parts, i hate shite that doesnt work properly and ends up meaning i have to redo the job.
I've seen the likes of this:
https://www.turnerengineering.co.uk/stc-4082-v8-gasket-set-top-c2x20634423
Turners have a good name, so i'm hoping this is a decent kit, but anyone know?
Is it worth looking into any of the aftermarket upgraded bits like Cometic Gaskets or ARP head bolts? Most modern engines use MLS gaskets so they're clearly superior, but do they work properly on an old thing like this?
I also need to reseal the front timing cover and fit a new alloy sump pan, any gotchas here?
Also pondering, do i pull the engine out the car? or is it okay in situ?
I've been thru a few MAF's, they're impossible to buy new, and copy ones are junk. I was tempted to try and datalog airflow against voltage, and figure out an adaptor to run a modern Bosch MAF on it.
I can easily acquire the voltage/airflow curves for a Bosch MAF, but the Sagem/GEMS MAF seems impossible to find, and ofcourse datalogging a broken one gives you useless data, so i've never bothered going any further. Someone who can tune the GEMS should be able to pull the airflow table out of the stock ECU, but i've never managed to find anyone willing to actually do it.
However the one i'm using now seems alright.
i suspect this job is going to snowball 😂
okay so as one might have expected in hindsight, the brake override doesnt actually stay enabled once you start driving. Its spring loaded in such a way that it pops out again.
I did notice very visible pitching of the trailer on the motorway, the nose of the trailer bouncing up and down with a very close correlation to the jiggling the car is experiencing.
So i guess we're back to the original question, is it simply too much play in the hitch/coupling allowing the trailer to bounce around at a high frequency. A new hitch is £320 which feels like a lot of money if it doesnt fix it, although to be fair, it probably needs it regardless. Its more that it might be better to sell this trailer and buy something better instead of spending the money on this one.
I wonder this about mine. Its really flat at low RPM's and only really wakes up above 3k or so. Given its a big torquey V8 that doesnt particularly like to rev it seems a bit "upside down".
I want to change the headgaskets soon as i suspect ones a bit leaky, perhaps thats a good time to check the cam, however is there any easy way to check for wear, or am i going to have to remove it and carefully measure everything?