RR 4.6

[H-M3]

Hi peeps first of all a BIG HI to all I am a new member and thankfully good old goggle bought me over this side.


Anyway I have a RR 4.6V 2001 model, I had it fitted with a Romano multipoint around June 2005. Since installing I was only getting around 150ish miles to 95lt tank I had it looked over under warranty few times they say they have tweeked it up etc but recently I am getting 120 if lucky in town! I serviced the car at the stealers around 3000 miles ago I put new Plat NGK sparks in there. Since then around few weeks ago it started to misfire mainly on gas but now on both!
Sorry If this has been asked many times would the gap in the spark have any effect and would the HT OE 3years old have any input?? I am so upset with all this as I am getting better mpg on petrol then gas for a starters and now the missfire!! AAARRGH!
Please help me or I will burn the damn car!

I have ordered new Magnicor ht leads and the spark gap has been adjusted.

Thanks and sorry for the long thread.

[AndyV8]

Hi, I'm also new but hope I can be a bit of help on my 1st post!

Remember that lpg tanks only hold 80% of the stated capacity so will only hold 78-79 litres. That said consumption does seem high.

Some peeps will say not to use platinum plugs as they can have a detrimental effect. LPG needs ignition system to be spot on therefore regular (2 years seems the norm) plugs, HT leads, dizzy cap & rotor arm changes are recommended. A word of warning - use OE cap & rotor and, if same as Disco, make sure and hold the 8 pointed star thingy (great technical term) down when taking of the rotor.

Your consumption should be better on petrol than gas, gas tends to be 10% ish less.

Hope this helps, Andy

[H-M3]

Thanks Andy and welcome to the forum dude. I was recomended the ngk's by ngk itself. Also I dont think my car has distributor as its a later model. I think it has a coil?

But I am getting very low mpg on gas I know that you get slightly less mpg on gas than petrol, but come on 120 with a full tank I think thats absurd.

Thanks for your input tho dude and what car do you have?

[AndyV8]

Hi H-M3,

I agree, you should probably be getting about 150-180 round town I would think. No dizzy - one less thing to worry about! I may have been getting mixed up about platinum/iridium plugs but if that's when your problem started maybe not! Plat. may be good for petrol but not for lpg maybe! Check leads & coolant level

I have a '96 3.9 V8 Disco for my sins.

[H-M3]

Thanks guys, I think I will give the leads a go and see what happens, So you are saying that there is no need for the platnium sparks then? I think they are ngk prfn-11 or something. How hard is it to change the ht leads? Can I do it myself, I am quite good with the odd spanner?
Also my coolant seem to drop a fair bit after the lpg conversion. Is that normal?

Thanks guys, is there anyone nearby that can have a look for me if problem still persists? As I would like a second opinnion.

[H-M3]

Thanks rossko, I will leave it with the pros then.
I hope its not a headgaskit job! Im not losing alot of water just bit. But it does a say in my lpg manual to check coolant weekly. I guess where the engine is running alot hotter it uses more water

How do I determine when to change the coil? Is there any wear patter or lifespan on these?

Thanks

[Dave K]

You may find you are losing water under pressure from the crappy plastic T pieces that are used where the system is connected up to the cars coolant system

[H-M3]

You may find you are losing water under pressure from the crappy plastic T pieces that are used where the system is connected up to the cars coolant system

So whats the cure for that dude?

[Dave K]

I used some sort of water leak cure in the system, Halfords have it. I also carefully!!! checked the tightness of the jubilee clips on mine which only turned a fraction but enough to stop the high pressure drip. They seem to loosen every few thousand miles.

[H-M3]

thanks will check.

[PEGASUS]

Hi
I also run a 4.6 p38 range rover with a 95 ltr tank and i get about 150 miles out of a tank of gas around town.
Try to find the leak rather than put any leak repair fluid in as the p38 has a very fine radiator and it blocks really easily, and the last thing you want is one of these engines overheating.
Good luck
mark

[H-M3]

Thanks everybody for your kind help, I think I have sorted it guys! I have replaced the ht leads with some magnicor ones yesterday. It seems to run fine now. Lets hope it stays like that!! Word of advice to evryone with lpg change the oe ht leads as they are @!##!! My mechanic said they were burt inside by the looks of it.


Thanks everyone for there input.

NB: originally I did get around 150 to the tank and more but it started to deteriate after a while. i am assuming its the ht fault.

[PEGASUS]

Its good to know you have it sorted, here is another thing you can check it helped my mpg and how smooth the engine run.
Get a volt meter and put it on the body of the alternator and the negative on the battery, now i know it sounds silly but there should be voltage there, if it is higher than 0,12 then you need new eart cables, ideally it should be 0.02 to 0.04. These cars have massive problems with bad earths and it does affect the fuel consumption, and general running of the motor.
Hope this helps.
All the best
Mark

[H-M3]

Hi guys, just one last thing would it be wise to get the car recalibirated after the change of the ht leads as I am still getting poor mpg!! at the moment my trip computer shows avrg 9.5mpg!!! Also I am getting a nasty smell sometimes from the engine bay when it changes over to gas.

Pegasus: could you please clarify where should the +/- of the volt meter go exactly please?

thanks and also which earth leads?

[H-M3]

Don't rely on the trip computer, it calculates MPG based on assumptions about how it is using petrol, it will never accurately report on LPG. You'll have to work it yourself the old fashioned way

But even on petrol that does not seem right for sure?

[PEGASUS]

Hi H-M3
Hope this is a little clearer, as silly as it sounds a bad earth on a p38 can affect everything from lights to engine management. This is for the main earth cables from the battery to chassis and chassis to engine.
Start the car
Turn on high beams, demisters, max heater blowers, heated seats etc.
Prepare to measure the voltage between the negative battery terminal and the alternator body. Yes, I know they are both earth points and you may think there will be no voltage but in fact there will. What we are measuring is the health of your earth circuit, and it doesnt matter which way around the +/- of the voltmeter are.
Hold at 2000rpm (not more)
Voltage should be less than 120mv (0.12 volts). If it is higher, clean earth points and or replace cables.

[H-M3]

Hi peeps one problem after another!! my car was backfiring recently so I adjusted the gaps on sparks and I got my local garage to change the HT to magnecor! Backfire issue seems to be ok now but the car runs shite on petrol! It is lot smoother on gas then petrol. This is very confusing. I know I have to get it reclabirated but why has this problem happened now? These trips down to the installer is getting on my T###S! Also now when I put my foot down the gas gauge starts flashing and goes over to petrol. Also there is some nasty smell some times when it changes over to gas.

And And I ONLY get 100 miles to the full 95lt tank!!! I wish I didnt do this damn conversion!!!

This is a romano kit 20 months old still under warranty on RR 4.6 2001.

Thanks

NB: can anyone recommend me a good lpg garage near london apart from
Battersea autogas where I had my installation done!!!

[H-M3]

MY coolant has recently been flushed and replaced new. When I got the lpg done there was no sign of water loss but this just happened few months ago.
Petrol seems to be poor aswell. I will put £20 worth in but by just starting on petrol it still will not last more than a week!!!

My car does have a small oil leak I can see, but would that couse the poor mpg?

I get around 103 miles to the full tank of gas 95lt if thats any good. Also inregards to the change over to petrol, this only happend when I put the new ht's.
I am going to get it retuned up again and see where it goes????

thanks

[H-M3]

MY coolant has recently been flushed and replaced new.

Okay, we'll get there So there is no coolant loss at the moment, but it has recently been flushed.

I would suspect an airlock in your vaporiser *if* it is mounted relatively high up in the engine bay. That would give the "drops back from LPG to petrol unexpectedly" symptom.

Petrol seems to be poor aswell.

Okay, no point in tuning gas then, attention in the wrong place. The gas relies on almost all of the petrol system working correctly too. You need a knowledgeable Land Rover person to look at it.

My car does have a small oil leak I can see, but would that couse the poor mpg?

Shouldn't do, though on rare occasion I have seen oxygen sensors fail due to mucho oil on the outside of them - it can seep into the innards and poison them. That shouldn't happen on a Land Rover as they use genuinely sealed sensors, unlike most makes. But as the most obvious symptom of a failed oxygen sensor is appalling economy its worth bearing in mind!

cheers, Ross K

Thanks Rossko.

Sorry for the delay was really busy last few days.Anyway I for got to mention. The car got worse since i changed the ht leads. It now shakes/drives poor on petrol but funny slightly better on gas! ???

They are magnecor leads by the way. This is so confusing???

Please help.

[H-M3]

Thanks but where can I get hold of a text book??/