RangeRovers.net Forum banner

1 - 10 of 10 Posts

·
Registered
1995-2002 Range Rover P38A
Joined
·
99 Posts
Discussion Starter #1
hi guys! my first post to the forum

i've just bought myself a 1990 classic thats been converted to lpg. i know nothing about the conversion, how to set it up etc etc

some things i hope you may be able to help me with...

i've heard some systems automatically adjust the timing depending on the fuel in use.. how do i know if mine does this? and does anyone know what lpg should be timed to on the 3.9?

also, i was told the lpg system needs to be checked/adjusted regularly.. now bearing in mind theres no O2 sensor, so i cant use an AFR gauge.. whats the best way to do this? do i go thru the 'set by ear' routine? will this be good enough to get it running well? or is a exhaust gas analyser more appropriate to fine tune? if so does anyone know what the CO reading should be?

sorry for all the questions but i have to start somewhere!! and i havent seen these questions asked (that i can find!)

one last thing.. air intake.. the inlet opening on the filter housing is mighty small for a 3.9L engine!? much smaller than on my 2.8L bmw.. and more inline with the size of opening on a 1000cc morris i owned many moons ago! should i be looking to improve this?

thanks a lot guys

nev
 

·
Registered
Joined
·
536 Posts
Giday, and welcome.

I rekon LPG on a rangie is the best invention since the wheel period!!!
First off; no your system won't adjust the timing for the difference in octane rating between unleaded and LPG. This is due to the Lucas 14CUX injection system which your car has not running a knock sensor, and thus being able to sence the optimum timing for your fuel, load, revs etc. My car runs standard timing, not quite sure what that is off the top of my head. Mines a low compression Australian model if that helps and it runs just as good as petrol etc top end power. Some people also say to run a slightly cooler spark plug to compensate for the lpg running hotter. I don't and my dad didn't, and his car did 1.4 million km, with the majority of that done on LPG.

The system once tuned shouldn't need regular adjustment. It should be set and forget just like the co content of your fuel injection system. Most of them are tunable for either power or economy. If you post some pics. I may be able to tell you how to tune it for either.

Does you car idle correctly, or / can you smell gas out the exhaust pipes?

Hope this helps.
 

·
Registered
Joined
·
85 Posts
i've heard some systems automatically adjust the timing depending on the fuel in use.. how do i know if mine does this?
I think you may be referring to the systems produce by RPI among others, see the link for info on this device and there is also a bunch of other info on V8 engines and LPG on their site. http://www.v8engines.com/faq-lpg-ign.htm#advance-ret

This site also has some useful info on LPG with Range Rovers. http://www.iwemalpg.com/RR46-40.htm

Hope they help, if you need more help then let me know as I have somewhere a whole set up guide for the LPG system I fitted, if I can find it I may be able to scan it for you.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
99 Posts
Discussion Starter #4
hi guys

thanks for all the useful info! i think i'll be occupied at the weekend now!!

heres some pics to help (possibly):
http://www.nevstah.co.uk/lpg/IMG_0151.jpg
http://www.nevstah.co.uk/lpg/IMG_0152.jpg
http://www.nevstah.co.uk/lpg/IMG_0153.jpg
http://www.nevstah.co.uk/lpg/IMG_0154.jpg
http://www.nevstah.co.uk/lpg/IMG_0155.jpg
http://www.nevstah.co.uk/lpg/IMG_0156.jpg

when i got it, i made a note of how many turns from fully in each screw were, so i have a base.

it was smelling terribly of gas from the exhaust, so i tweaked all of them in a bit. it seems to smell less.

it idles ok 95% of the time, sometimes its a bit too low revs, but i dont think thats down to the mixture entirely as its usually ok. it sounds fine at idle and revs ok. but i'm concerned i dont want to be running it lean and looking to cause problems associated with a lean engine in the future!

cheers

nev
 

·
Banned
Joined
·
1,162 Posts
If you really want to set it up properly, get an O2 sensor and fit it in the exhaust. The O2 sensor will put out between 0 and 1 volt depending on whether it is running rich or lean. You then simply need a multimeter to read the voltage. To fit to the exhaust you find a nut that fits the O2 sensor thread, drill a hole in the exhaust near to the engine, and weld the nut over the hole and fit the O2 sensor. If it is running lean you will find that it will not rev out and basically go worse when you try to accelerate. If it is running rich you will find that you have no power. With LPG power and economy go together. LPG hates running rich. I use to pay a LPG specialist to put my Rangie on a Dyno each year to tune it. I wanted to play around the airflow a bit and they stopped doing the Dyno tuning on a Saturday (I could not get there during the week), so I purchased an accurate wideband O2 gauge. I found that the people tuning it on the Dyno had never bothered to set it up properly. By tuning it myself with the help )2 gauge, I increased my range out of a tank of LPG by 30% and obtained a very noticeable power increase at the same time.

I have recently had LPG fitted to another Rangie and Discovery. We have to have them fitted by LPG specialists by Law. Both times they were presented to me tuned very badly. They get away with this by people expecting a drop in power and economy from LPG and not querying the poor tunes.

So my advice is get your own gauge and tune it yourself. The gauge will pay for itself from better fuel economy and the smile you will get from the extra power.

By your photos, dump the system you have. The ring type mixer you have is not very efficient and upsets petrol running.

The large adjuster in the hose going to your mixer is the power adjustment. This sets the mixture above idle. Screw it in to lean the car off and out to get it to run richer. The adjuster on your convertor (vaporiser) that looks like it is a copper colour in your photos is the idle adjustment. The best way to set your idle (if you don't have a O2 gauge) is using a vacuum gauge fitted to your intake manifold.

Around town of LPG I get around 22 to 23 litres per 100 Kms. On a trip I would get better than 20 litres per 100kms
 

·
Registered
Joined
·
1,395 Posts
Just to clarify a couple of points in Ian's informative response. You will need a wide band O2 sensor (as opposed to the normal factory fitted narrow band) and you should be able to buy weld in O2 sensor bungs (as opposed to having to find the correct nut) from a good exhaust/tuning shop.
 

·
Banned
Joined
·
1,162 Posts
rufant said:
You will need a wide band O2 sensor (as opposed to the normal factory fitted narrow band) and you should be able to buy weld in O2 sensor bungs (as opposed to having to find the correct nut) from a good exhaust/tuning shop.
You really only need the standard narrow band O2 sensor to get it reasonably close. I have both as I often play around with things and I want very accurate readings. But to keep an eye on things and to know whether it is close, a narrow band is fine.
 

·
Registered
Joined
·
300 Posts
Nevstah said:
hi guys! my first post to the forum

i've just bought myself a 1990 classic thats been converted to lpg. i know nothing about the conversion, how to set it up etc etc

some things i hope you may be able to help me with...

i've heard some systems automatically adjust the timing depending on the fuel in use.. how do i know if mine does this? and does anyone know what lpg should be timed to on the 3.9?

also, i was told the lpg system needs to be checked/adjusted regularly.. now bearing in mind theres no O2 sensor, so i cant use an AFR gauge.. whats the best way to do this? do i go thru the 'set by ear' routine? will this be good enough to get it running well? or is a exhaust gas analyser more appropriate to fine tune? if so does anyone know what the CO reading should be?

sorry for all the questions but i have to start somewhere!! and i havent seen these questions asked (that i can find!)

one last thing.. air intake.. the inlet opening on the filter housing is mighty small for a 3.9L engine!? much smaller than on my 2.8L bmw.. and more inline with the size of opening on a 1000cc morris i owned many moons ago! should i be looking to improve this?

thanks a lot guys

nev
Hi Nev,

Take a look at Simon Hobsons site: http://www.diy-lpg.co.uk/Welcome.html

Also: http://www.lpgforum.co.uk/
 

·
Registered
Joined
·
1,395 Posts
rufant wrote:
You will need a wide band O2 sensor (as opposed to the normal factory fitted narrow band) and you should be able to buy weld in O2 sensor bungs (as opposed to having to find the correct nut) from a good exhaust/tuning shop.
You really only need the standard narrow band O2 sensor to get it reasonably close. I have both as I often play around with things and I want very accurate readings. But to keep an eye on things and to know whether it is close, a narrow band is fine.
Interesting. I might have to play around with mine at some point. Cheers.
 

·
Premium Member
Joined
·
1,703 Posts
ahhh LPG I spent half the weekend getting both the rangies running better on LPG, both mine had failed fuel pumps :( not fun to replace!

I have a little black box computer thingo on mine which plugs into an o2 sensor, and I simply adjust my idle screw on my converter to show that as flicking between rich and lean and then turn the screw another quarter to keep it rich at idle. The company who fitted my lpg said the rover V8 prefers to idle rich and run slightly lean at power. I don't know how much truth there is in that but there work is great and I cant tell between petrol and LPG. I highly recommend running these cars on LPG.

Funnily though, the 3.9 classic gets about 24L/100 around town where as the 4.6 P38 gets about 21L/100.
 
1 - 10 of 10 Posts
Top