P38 Nicholson-McLaren SGi lpg system

Hi everyone!

I need advice from an 'expert' in lpg systems - if there is such a person!

I have a 2001 P38 4.6 HSE with a Nicholson-McLaren SGi lpg system fitted in 2005 - 4 years before I bought the car.

The car runs fine on lpg, but only until the engine warms up, then it starts to "miss." The colder the weather, the longer the car runs on gas before it starts to "miss."

I'm told that two of the injectors need to be replaced, but if doing so, would it not make sense to replace all eight whilst the head's off and half the engine's in bits? Sod's Law dictates that if I just replace the two dodgy injectors, one or more of the 6 old ones will fail within 10 minutes of putting the engine back together again!

Trouble is, it will cost at least £1000 to do this job right. Injectors cost maybe £80 each x 8 - so that's £640 before you start!

The 'payback' maths don't work because I only do about 5000-7000 miles per annum, and it will take maybe 2 years to get the £1000 cost back on fuel saving over the cost of petrol.

Should I:

• not bother fixing the gas system, and just continue running on petrol?
• spend the money and get it fixed properly?
• install a new - and maybe different gas system? After all, I already have a 95 litre doughnut gas tank, so that won't need to be replaced
• or.......what do you reckon.....? Selling the car's not an attractive option because it's done a genuine 48,000 miles and is otherwise in beautiful condition.

Please .....any help is welcomed......thank you....!!

Are you sure the gas injectors need the head to come off?
They are usually in the inlet manifold between the heads.

Just done a quick google they are still in business take it back to them to have a look at.

Gas injectors different to Petrol injectors Head shouldnt need to come off. gas injectors are cheaper than the petrol ones. Go see an LPG specialist.

Thank you 'lowfat' and 'discomalc' for your swift replies and your expertise.
I only assumed that the head had to come off because pots 2 and 5 have been electronically diagnosed as those where the injectors need to be replaced, and thought that the injectors would be immediately adjacent to the pistons. [You can tell straight away that I'm an "expert" can't you?].

I think the only head coming off at the moment is mine!!

The people who I have approached about this problem include:

• Barry Kenworthy of Maple Garage, Sproatley [Hull area]
• Steve Spinks of South Lincolnshire Autos [Spalding area]
• Colin Todd of Lakeland Landrover [Coniston, Cumbria]
• Neil Mugglestone [Boston, Lincs]

These 4 were recommended to me by Nicholson-McLaren as 'experts' in N-M lpg systems, and I don't doubt it for a moment. The only two I've actually met are Barry Kenworthy and Steve Spinks.

Steve said it wasn't worth spending the money to put the gas system right, because at £1000+ he has a point, because 'payback' would take maybe 2 years at the low mileage that I do.

I think my "real" problem is knowing who to trust to put it right. This is why I wondered if installing a brand new system might make just as good sense economically, because I'd get at a 12 months warranty on the new system. I already have a 95 litre doughnut gas tank in the spare wheel well, so wouldn't need to buy another one; that must reduce the cost of a new-install??

The next problem would be which system to install......and so it goes on and on....

What would either of you two guys do in my position.....?

Would you spend the £1000 + or just forget the gas and run on petrol....?

I'd love you opinions......be as rude as you like!!

Thanks

Mike

Why would you assume all 8 injectors need replacing? Or for that matter why 2 would need replacing.
I can't see as they'd wear, so perhaps you just need em cleaned.
I might be talking bollox though. I know little about lpg systems.

jonbill said:

Why would you assume all 8 injectors need replacing? Or for that matter why 2 would need replacing.
I can't see as they'd wear, so perhaps you just need em cleaned.
I might be talking bollox though. I know little about lpg systems.

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Hi jonbill

Thank you for your response, and of course you're right......and I know less about lpg systems than anyone else on the planet! Trouble is, trying to find someone who genuinely knows about lpg systems - and especially mine - is the biggest challenge!

Think I'm going back to bed and pretend none of this ever happened!

lowfat said:

Just done a quick google they are still in business take it back to them to have a look at.

Click to expand...

Hi lowfat......

Just to let you know that I'm taking your advice and have booked the car into Nicholson-McLaren in Wokingham on Monday 18 July. They'll diagnose the problem [hopefully] and, depending on the diagnosis, I'll either let them get on with it there and then or take it back when I can arrange a better time.....as it is, I'm having to book into a B&B on Sunday night, so that's another £65 down the tubes!!

I'll let you know what happens, but thanks for your advice.

Hope it goes well....

Have run LPG systems since Adam was a lad. Sounds like a totally different problem to me. LPG arrives at your engine bay in liquid form (hence LPG) then through a heat exchanger warmed by engine coolant, this turns it to gas and then its passed through your injectors. Let the 'experts' look at at, it sounds like a cheaper fix than changing injectors or whole system. If you are committed to fitting another system, consider the Prins VSI system. Its perfect for the V8 engine.

Hi
Had a similar problem and took it to LPG expert in Northern Ireland needed a new condenser at a cost of £250. Not saying its going to solve your problem but its worth getting checked

Hi
Had similar problem. It was the condenser and cost £250 to fix. Check that before you go any further,
Digel

Johnny Fart Pants said:

Have run LPG systems since Adam was a lad. Sounds like a totally different problem to me. LPG arrives at your engine bay in liquid form (hence LPG) then through a heat exchanger warmed by engine coolant, this turns it to gas and then its passed through your injectors. Let the 'experts' look at at, it sounds like a cheaper fix than changing injectors or whole system. If you are committed to fitting another system, consider the Prins VSI system. Its perfect for the V8 engine.

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Hi Johnny Fart Pants....

G'day Johnny and thank you for your words of encouragement.....I sure as hell need some!! As you know, I'm taking the car to Nicholson-McLaren Engines on Monday 18 July who are the suppliers of the existing lpg system. Anything but replacing 8 injectors has got to be good news.....let's hope you're right!!

See you some time after Tuesday probably....

lowfat said:

Hope it goes well....

Click to expand...

Well, back from Nicholson-McLaren and the news isn't good!

Their diagnosis is limited because they need more time to fully check things out.
However, whatever else is wrong with the lpg system, they said that the vapourizer was leaking and needed to be replaced anyway! That would be at least £250 plus vat and labour!
Nicholson-McLaren don't currently market an lpg system suitable for a Range Rover, and they suggested that I had a new 'front end' installed. They recommended Prins and gave me two installers to check out.

One is in Doncaster and I rang them.

They quoted £1600-£1700 to install a Prins 'front end.' Trouble is, even if I decided to sell the car, I'd have to fix the lpg system 'cos who'd want to buy it with a faulty lpg installation.

So, I'm back to the original options......in the meantime, I'm going to just run on petrol until I can decide which is the best way to go.....

:welcome2:hi, looking at your post ,i have a 2000 vogue with a thor engine and lpg system ,it runs perfect at moment but i have a great guy who installed it and services it regularly. firstly you need to have it serviced with a new filter fitted and trims re set ,this should only cost you £50/60.00 any more and there ripping you off , they should at same time put it on their engine management computer system to set it up properly. let us know where your based then perhaps we can help you . the guy that installed mine is great and a registered approved installer , as there is a lot of pretend masterminds about you need to be sure that only someone who knows what their talking about works on it ,,it might just be something to quick fix and inexpensive ,,so think on ...if you p.m. me ill give you my number and hopefully put you in the right direction .cheers for now mozz.