RangeRovers.net Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
210 Posts
Discussion Starter #1
I have an LPG system fitted to the p38, it seems to be quite a basic single point system, I've been unsure on how it works etc and have just left it alone for now but after taking it out for a run yesterday and things going well I though I'd give it a try.

So I Started up on Petrol (I presume!) waited a few seconds then flicked the switch, within a second the car had cut out. I flicked it back to petrol and restarted, I then held a bit of revs on to get it up to about 2000rpm and flicked the switch back to gas, this time I didn't even notice a change of note it just carried on running, I released the throttle and it continued to run. I left it running a few minutes then flicked the switch back to petrol, the revs dropped down quite low but then it recovered and carried on running.

Does that all sound normal?

Does anyone have this system and know what the lights mean etc - I presume they are someway of showing the remaining gas in the system? I'll take a photo of the box with the switch on later, but if anyone has a similar system it would be useful to know.

Many thanks
 

·
Registered
Joined
·
442 Posts
G'day mate, Does your car have an Impco mixer,?
Does it if you leave switch on LPG ,start on petrol and automaticly switch to LPG?
Yes when switching from LPG to petrol or vise vera you must have at least 2000rpom for switch over this is done stationary only.
Instrument cluster last LHS switch for LPG with led indicator for gas level when,four stage green and last green goes red ,then when nearly out of gas it will flash on /off.On petrol it iluminates yellow only on top.
Does that sound right for you
 

·
Registered
Joined
·
234 Posts
I Have the same system, single point impco etc, yes it does exactly what you describe and mine has run with no probs since 2006. Just watch your water level, as it will freeze if it runs out, if it does just refill and run on petrol for a bit then flick back over. Mine does drop in revs when it has been on petrol for a while (not too long at £116 a litre) at first switch over the O2 sensors need to catch up i think, make sure you run petrol once in while for a bit to correct your adaptive trim levels.
It an ok system simple tech anyway, may get a few more miles out of multi point but lots more hassles and cost.
cheers
Onetime
 

·
Registered
Joined
·
210 Posts
Discussion Starter #5
Will get some pictures up as soon as possible,

My system consists of a large tank in the wheel well, a a vapouriser in the engine bay with a pipe leading to the air intake tube, and that's about it other than a small black box with a switch and a few LED's on it.
 

·
Registered
2010-2012 Range Rover MkIII / L322
Joined
·
49 Posts
Hi, LPG system is designed to start on petrol then switch to LPG automatically when 2 conditions are met.
1. The running temp must be up to what evr has been set as switch temp.
2. Revs = whatever set as switch revs, typically about 2000rpm.
Therefore on a cold day you will run on petrol for noticably longer than a warm one.
Normally once car started and warm, for rest of day switch is virtually instant unless parked and left to go cold (again depends on hot/cold day).
Normally there arre a series of green lights on switch, all on = full all off = empty 2out of 4 = half full etc.
These are about as much use as a chocolate fire-guard on most systems.
Fill it up.
Run till empty.
Note mileage.
Fill up 10 miles before this in future !!
 

·
Registered
Joined
·
210 Posts
Discussion Starter #7
The switch has two positions, one points to a petrol pump looking symbol - so I presume this means it's on petrol only. On the other side there are two lights, one orange and one green. Above the Orange one is the letter "G" and above the Green one there is the letter "R". If the engine is off and I switch it towards the leds then just the Orange light comes on, if I then start the car when it's running on Gas the green light comes on.

I tried today starting from cold with the switch set to gas. The car started instantly like normal but then within a second the revs dipped to about 600rpm then recovered. So it seemed to switch more or less straight away to Gas without the revs going above 2000rpm.

There is a bit of a different smell from the exhaust when the car is running on gas - I presume this is normal?

So at the moment I have no idea how much gas is in
 

·
Registered
Joined
·
210 Posts
Discussion Starter #8
I found a picture on the internet of the same electronic box as I have:



So I presume I must have the additional lights (just can't see them) and that more will light up when there is more gas in
 

·
Registered
Joined
·
210 Posts
Discussion Starter #9
I've now managed to find some instructions for my Electronic Control Unit:

http://www.iwebgas.com/Download/autoswi ... tronic.pdf

Not 100% sure which model I have but I thought it might help others out

From what I just read quickly it sounds like it switches to gas when you hit a certain RPM (don't think it worries about temperature). You can adjust the RPM on the back of the unit
 

·
Registered
Joined
·
517 Posts
If it doesn't have any temperature setting available I would start and run on petrol for about 1/2 mile from cold. LPG systems really don't like running cold - hence the reason all current systems have this facility. The gas pressure will be a little low and under heavy demand the vapouriser could freeze up dropping the gas pressure enough to cause the engine to cut out.
 

·
Registered
Joined
·
53 Posts
Thats the same system I have on mine.

I bought the car last May and it would start up on petrol then switch to gas it's self until christmas then it would start up fine on petrol then die when it swapped it self to gas :think:

Now if I start it on petrol then switch to gas when it's warm its fine.....

So why did it suddenly start doing this????

Could it need new plugs??
 

·
Registered
Joined
·
517 Posts
Jollygiant said:
Thats the same system I have on mine.

I bought the car last May and it would start up on petrol then switch to gas it's self until christmas then it would start up fine on petrol then die when it swapped it self to gas :think:

Now if I start it on petrol then switch to gas when it's warm its fine.....

So why did it suddenly start doing this????

Could it need new plugs??
The weather became a lot colder around christmas and the lpg needs some heat to help vapourise and maintain an adequate gas pressure to ensure mixture is rich enough - that's why the vapourisers are plumbed into the car's cooling system. Also the simple non lambda feedback lpg systems have no method of enrichening the mixture for a cold engine. Think back to pre injection cars - to start from cold you had to use a choke to do this, the RR has sensors to determine engine temp and it will then alter the petrol fuelling for cold starting - the lpg system will not do this.
 

·
Registered
Joined
·
53 Posts
Whilst we're talking about this how do you service the LPG system???
 
1 - 13 of 13 Posts
Top