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Joined: Jan 06 2016
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Now that my LPG system seems to be running properly, I thought I'd do a fill to fill from the same pump, mixed conditions consumption check. The trip to and from Summer Camp and some local running around seemed like an ideal mix of conditions. <br>
I'm getting 3.265 miles/litre <br>
I'm wondering how that compares with others on single point, multi point and 4.0 and 4.6 L <br>
Anyone prepared to share their dark secrets?!

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Joined: Dec 30 2015
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Yep, I need to do a proper brim to brim from the same pump comparison but at the moment I've measured 2.8 and 2.9m/l from different fillups between different pumps (140m/50 litres and 205m/70 litres approx)
4.6 and multipoint

Maybe the drag will reduce now I've had the tracking sorted :)

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Not a completely fair comparison as I filled up at a Texaco station near me before setting off for the Summer Camp and the next fill was at a Shell station on the way back. But after a combination of cruising at 75-80mph, running around the lanes to the hotel and back and a lot of mucking around in low ratio with a dead Disco on a bit of string I took 60.8 litres after a combined 191 miles, so 3.1415 (almost Pi, is this significant?) miles per litre or 14.26 mpg. As my tank takes 67 litres to full, that would give me a range of 210.5 miles to a tankful. I've seen a bit better than that but I've also seen a lot worse so reasonably happy with it. If I can do better than 200 miles on a tankful, I'm not complaining. I also think the LPG is still running slightly rich so it could be bettered a touch.

That's a 4.0 litre on a singlepoint LPG system. But as you say, ideally you need to average it over multiple fills from the same pump although even that isn't completely repeatable as the ambient temperature and the temperature of the tanks at the filling station will make a difference too.

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Joined: Dec 30 2015
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I'm a bit gutted because we were regularly seeing 240 from a tank (74l useable volume) before I changed the upstream O2 sensor on bank 2. That would mean a rough average of 3.2 miles/l which seems consistent with what you guys are reporting.
I noticed some adaptation out of range errors when I was messing with the nanocom tonight and another O2 sensor error for the other upstream sensor. I'll recheck in a couple of hundred miles and see if they come back. No misfires this time.

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Joined: Dec 29 2015
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2.5m/l approximately. I wonder if sorting out the big boomy boxes where the cats used to be and sticking a cam that actually has lumps on it will improve matters...

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Joined: Jan 06 2016
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I'm more than happy with the range that I'm getting with my twin tanks (135L water capacity). Got to 330 miles before I wussed out thinking I could detect the slight hesitation that is the precursor to running out. <br>
Morat- did you reset your adaptives when you changed your O2 sensor? They take a while to settle after doing that.

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Gordon, your problem is almost certainly due to the lack of lumps and the size of your right foot, I've been in your passenger seat remember.

Morat, if you did reset the adaptives and have still had out of range errors, the gas system definitely needs a recal. If it was calibrated with a dodgy O2 sensor, then it will be wrong.

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Joined: Dec 30 2015
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If you have a dodgy O2 sensor on the other bank, then it will also probably throw things out....

I'm currently on a fill-empty cycle to see what my mileage is like on gas. Now it's running a somewhat properly I filled up before Summer Camp and got 60L into the tank, which meant I had a total fill of about 75L.

Including the to/from summer camp, and the trip down to London yesterday, I'm up to about 150miles on the trip computer.

I got to about 160miles last time before I filled up and I reckon I had about 15L left.

Computer in the RR showed an MPG of 14.3mpg before I came to London, and showing 15.0 when I arrived.

I'm going to run it on gas tomorrow until I get to 200 miles (about half way home I think) or until it runs out and switches back to petrol - whichever comes first! Then I'll refill when I get home and post my figures up too.

I think it might be running a touch lean still under load as 50-70mph acceleration is a bit gutless, but I think it is also doing it in top gear with the torque converter locked up unless I really poke the throttle.

Figures in a couple of days...

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Martyuk wrote:

I think it might be running a touch lean still under load as 50-70mph acceleration is a bit gutless, but I think it is also doing it in top gear with the torque converter locked up unless I really poke the throttle.

Almost certainly. Mine is locked up in top at that kind of speed and if the revs are below 2,000 it doesn't have a lot of interest in the throttle unless it is given a good prod. However, I did discover on the way back from the Summer Camp that if, when travelling behind a truck at 40 mph, the Sport button is poked and the throttle floored, it drops down at least two gears, takes off like a scalded cat, revs up to 5,000 rpm before shifting up and sounds bloody wonderful!

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Joined: Dec 30 2015
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I did that off the lights once I had put the old LPG map back in the ECU... sport button and a dollop of right foot (not even all the way to the carpet!) And away she went up to about 4500 and before I knew it is was doing closer to 50... with a smile on my face...

Think I might just have to use sport mode a bit more.... haha

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Joined: Mar 22 2016
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Gonna have to fill mine and see what mileage I get, cars comp is saying average 18.3 at the mo, despite playing cat and mouse all the way back with a sport and a 405,,

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Joined: Dec 30 2015
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Curses! I reset the adaptation values at lunchtime and went into town and back. Adaptive values out of range for both banks and O2 sensor fault bank1 upstream. Not much point getting it re-mapped until I change the other O2, I guess. Still, it means there's probably more to come :)

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It can be a bit of a pain to get it all running right again... I've been through all that over the last year or 2 with mine (because I've been away so much, I haven't been able to dedicate the proper time to it in one go...

But if it won't run right on petrol, then the running on gas will throw things out even more... well it did on mine!

If it makes you feel any better, I still occasionally get P0172 and P0172 (adaptation on bank 1/2) codes come up in the engine ECU, even though it feels it runs properly. I think in my case it's because the gas system needs a tweak, but at least it actually runs nicer on gas now and doesn't throw the trims out within a few miles of driving like it used to...

Get the O2 sensor replaced, reset the adaptives, and then run it on the expensive stuff for 100 or so miles for the petrol ECU to adapt back to where it should be (it will have slight adaptations to account for sensor tolerances and engine wear) and then see how she goes on gas again...

Lambda Sensor

There's one listed on eBay for £45 plus postage... Genuine Bosch/Land Rover boxed.

MHK100940 is the part number if that helps..

Marty

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Joined: Dec 30 2015
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Ooh good spot! Purchased :)
Thank you very much. I'll swap that over next week. I hope the nanocom wasn't doing the same thing with swapping the fault code over as it does for the ABS Sensors! Although, it's too late now - the old Bank 2 sensor is long gone.

I'll give Simon at LPGCCccc a bell and make sure he's available to do the tweaking once the petrol side is sorted.

Apart from the cost, this won't be damaging to the engine will it? I've got another long trip this weekend. I can take the Jeep but the Rangey is more comfortable.

EDIT: can a mod split this thread? I don't want to clutter this LPG thread with my engine woes :)

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Hmm, I've got mod status and can edit the post, delete the whole thread, lock the whole thread or highlight the whole thread but it doesn't look like I can split it unless I copied, deleted and then pasted the text into a new thread. But if I did that it would appear to have been posted by me.

Just leave it as it is, it'll wander back on topic, or not, at some point. It is still relevant as it's a cause of using too much LPG if anyone else has a similar problem.

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Joined: Dec 30 2015
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I should have a chance to crunch some numbers tomorrow...

I drove back from London (well Heathrow area) this evening and ran it on gas until I got to 210 miles (I was expecting it to conk out before then!) and a fair bit of that was in stop/start traffic - given it was Friday evening on the M4... though the crash near J14 didn't help either - but hey.

Observation so far... think I can probably tweak the map a bit more to richen it up between 2000-3000rpm, as after I switched back to petrol for the last 20 odd miles, it definitely felt like it had more get up and go when you tried to accelerate on the motorway, starting at 60mph ish. I'm planning on heading up to the workshop either tomorrow or Sunday to do an inventory, but will record all the parameters on the Nanocom and see what the injector timings are on petrol for that rev range and that will give me the area in the map to tweak a bit... If I can find my USB extension cable, then I could put the laptop on the seat with the LPG software on it and have a real-time read out and map...

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Joined: Dec 30 2015
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Ok, so the figures are in for me...

I've just been and filled up the LPG tank, and I managed to get 70.4L in - and for that amount of gas, I did 210 miles..
So, 70.4L equates to about 15.48 gallons, which maths comes back to 13.56mpg
A bit less than I was hoping for, but a lot of that was short trips, and the motorway journey back home was stop/start a lot of the way. The trip computer only says 15.4mpg with an average speed of about 27mph - so 13.5 on gas is probably about right.

Still at 55p/L, 70.4L = £38.72 to do 210 miles, which makes it about £0.18p per mile to run a 4.6L Range Rover...

And it works out at about 2.983 miles/L

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Joined: Dec 30 2015
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It could be rich....but I'd go richer first just to be safe.