Hi all

Finally got the car back from the repairers, took a week longer than expected but the end result was very good, to recap a Discovery drove in the back so had a new bumper and boot lid, lights etc, they managed to straighten the rear panel. Then two days later a tile fell off the roof onto the bonnet so I had that repaired as well.....
Well that left only two days this week to do the LPG install, I wanted to do it before this weekend as we are off visiting and will do about 2000 miles next week....
Some may remember I promised to do a write up on the fitment of a top of the range LPG Prins Vapour Sequential Injection (VSI) kit to the LS
I used to work for an installer so I have used his premises and equipment for this, it’s so much easier when all the necessary tools are to hand.
I didn’t take as many pictures as I intended due to the time pressure but the following will give an idea of whats involved.

This is what we started with.... looks nice and smooth....



After removing the cover we are left with this



The next job is to find a place under the bonnet for the hardware
A vaporiser (turns the liquid gas into vapour) A bracket was made to fit this to the top left of the engine bay, the bracket fixes to one of the servo mounting bolts and to the bracket for the power steering reservoir. All brackets are custom made from 3mm steel plate, they are painted with acid etch zinc primer then satin black, this usually outlasts most standard paint under the bonnet!!
The Prins ECU (computer brain) was fixed directly to the side of the original ECU housing with a bracket. The fixings were sealed to ensure water tightness of the housing. This picture is before fitting.



Two sets of injectors (control the input of vapour) Mounted by custom made brackets to the inlet manifold
LPG filter. This is very light in weight so is fixed via its short length of LPG hose to the vaporiser.
Emulators (help the original ECU to think the petrol injectors are working when they are not!!) These were fitted below the right middle plastic shield, they fitted very tightly and only needed a cable tie to prevent movement. You have to be careful of the ignition amplified that is under here as it gets very hot in use, it’s easy to see as it has alloy cooling fins.

Then the connections to the vehicle.

The heater hot water circuit (to warm the vaporiser) was made in two places for flow and return from the heater pipes that connect the engine to the heater within the car. Purpose made “T” pieces are used of the correct size and proper Jubilee clips used not the cheap pattern ones.
The nozzles into the inlet manifold (to supply the gas to the engine) are drilled and tapped into the inlet ports at the same distance from the valves on each cylinder.
Connections to the original ECU. All electrical connection are soldered and covered with shrink wrap to ensure perfect joints. Reference is made to the original wiring diagram and connections made. All eight cylinder injector wires are cut and connected to the emulator wiring (any fault in the LPG kit and the default setting is straight through to petrol so you cannot be left with no fuel if the LPG system fails) Additional connections are made for a RPM signal (usually camshaft sensor) Two Lambdas (the ones before the cats) Ignition switched live, permanent live, Ground. This is a picture of the cars ECU before connection.



This is the wiring loom of the LPG kit... it looks worse than it is..



This is the ECU after connections



So after all that you end up with an engine bay that looks something like this.....



You then have to wire in the dash switch, getting the wiring into the car from the engine bay is sometimes very difficult but Lexus are kind and there is a large rubber grommet next to the battery that comes out behind the glove box. You can have the switch virtually anywhere, I chose to keep the centre console looking original and fitted it next to the cabin air temperature sensor, if needed it can be removed and the damage left behind fixed cheaply by just replacing the small plastic trim piece. This picture shows the switch with a full tank of LPG, all four Led’s are lit, there is a built in sensor to dim these at night should they be in vision.



Next we move to the boot....

Originally I was going to use a 67 litre 4 hole tank as this fits without modification but unfortunately the one ordered for me had been used on another job as I was two weeks late in getting it converted due to the damage repair, so instead of waiting for another I found an 82ltr tank that was the correct depth to allow a flat boot floor but was a bit too big, so I had to do a bit of panel beating to get the tank box to fit, the tank fitted the wheel well exactly but the box hit the side of the boot, this was dressed back about an inch after checking underneath for clearance, anyway it didn’t take much but it did crack the paint so it was sanded and repainted both inside and underneath.
The tank is held in place with four brackets that bolt through the boot floor, these are made for each application to ensure the best fit.
An 8mm plastic coated copper gas pipe is connected to the tank and fed out the boot floor underneath the car and up into the engine bay, there are so many rules and regs on its path and its safety and security that they fill a book but it’s just a case of common sense, keep away from exhaust pipes, moving suspension etc, make sure it can’t get trapped or squashed if the car bottoms out.... The pipe is fixed securely with “P” clips. A multicore wire also runs from front to back to control the solenoid on the tank, and wire in the tank level gauge.



The next part is good fun or horrendously bad depending on your point of view, take one 70mm hole cutter and attack the rear wing of your pride and joy...... When you have a nice disc removed, you tidy up the burr then file two slots top and bottom to stop the filler from moving, paint the raw metal edge, spray liberally with rust preventer and fit the filler. I had mine colour matched to the car, they come in standard Black. A high pressure large bore fill hose connects the filler to the tank and you are nearly there. The advantage of a 4 hole tank over a single hole tank is that they fill much quicker as it uses one hole for filling, one for a pressure relief valve, one for the gauge and the last for the supply, The single hole tank uses one hole for all four things, they are a bit cheaper but take ages to fill up, a four hole fills about as quick as a petrol pump dispenses.



The filler and the tank box have to be sealed from the inside of the car and vented. The filler is vented from the fill up side. The tank box is vented through the boot floor. This photo shows the inside of the rear wing where the filler is.



This is the only intrusion into the boot the boot floor fits flush as before.



Next job is to fill the tank with gas, checking for leaks from the fill hose. Then connect a laptop to the Prins system and check all parameters are correct and to initialise the system, it is set to start on petrol and then switch to gas at 35 deg C, when hot it starts on petrol and changes after 0.5 sec. You do not have to rev it like the old systems.
The entire system is then checked for leaks and security.
An OBD11 reader is plugged into the car and it is taken for a test drive, I won’t go into all that’s checked but it usually works OK first time if setup correctly, you usually just check lambda readings and fuel trims.
When all is well and working as should be then it is time to tidy up the install, I cut the boot carpet to fit back around the tank and trimmed the tool holder, omitting the jack and handle as I haven’t a spare now anyway (apparently according to the AA the average motorist has a flat tyre every 97,000 miles, so I should be OK for a while)
Then tidy up the engine bay, wrapping the wiring in convoluted tubing etc. I had to trim the side of the engine cover to make it fit nicely, but I had checked it at various stages to ensure it would fit back easily.

So here is the finished engine bay



You can just see the filter at top left and the ECU at bottom right.

I have done about 200miles since I finished it and it has run perfectly, there is no loss of power, it is smooth and clean all the way through the rev range, the only way to tell it is on gas is to look at the switch.
One interesting thing is the petrol gauge, it still goes down and the distance to empty still falls, it’s between ¼ and ½ full and it drops until its nearly empty then jumps back up to the correct reading then starts again. This is because the gauge will only take sporadic readings from the tank (unless the level rises i.e. filling up) it then drops because the ECU knows how much petrol is being used by measuring the injector opening times and working out how much you are using, it also gets the MPG etc from the calculation, anyway because it still “thinks” it is on petrol the gauge drops.... a small price to pay for half price fuel....

If anyone has any questions then please ask.

Thanks and I’m sorry if I’ve bored you

Pete

Great post, really informative. Wouldn't mind getting mine done.

a neat and tidy job

very nice and professional looking job.

Interesting read, the rear quarter filler hole is seriously scary stuff though

Thanks for posting.

Sorry forgot about this when writing the thread,

Lexus official position on LPG



As you can see they do not condone it but they don't condemn it either, a lot of manufacturers will not even work on a car with LPG installed, all they state is that they will not cover defects caused by the LPG conversion and that whilst under warrantee they will charge extra for a service to check valves for wear.

The Prins kit comes with a 24mth warantee.

The LS engines either 400 or 430 do not suffer from valve seat recession, there have been problems with the 300 engine but a valve lube kit is available to help with upper cylinder lubrication and this will prevent wear, you can also take out a warrantee for a small fee to cover any valve problems, so all is covered.

This looks great - I am very interested in the cost and getting a professional installation. I have an 02 LS430 with 123K on the clock. A friend converted a 400 and did 250K miles in it before a major engine failure. His system was an old single point injection system and the problem caused by some of the valves carboning up - also LPG burns hotter than petrol which is supposed to cause problems with the aluminium engine.

One big problem I foresee is servicing - my local Lexus dealer told me that H&S rules prevent them from servicing a LPG converted car - any comments on that point. Half price fuel for a 6 year old 430 vs Lexus dealer servicing is not a contest.

I would be interested to know which section of H&S applies. Do the thousands of LPG converted vehicles not get serviced or is it that the dealership you use does not have technicians or premises(or both) that are up to the job.

The dealer is in Milton Keynes - Sytner I believe - and I expect it is their decision. Speakeing as an engineer Gas is safer than petrol to work with.

I intend to ask then what the problem is when (and if) I have the conversion done and will let you know.

Brendan

Cost for the above conversion would be around the £2000 mark.

Petrol’s peak flame temperature is 1977Deg C LPG peak flame temperature is 1990Deg C about 1% or 13Deg C more. Not that much to worry about........

Interestingly the flash point, the temperature where the mixture will ignite on its own is much less for petrol than LPG. Petrol is 428Deg C and LPG is 1004Deg C so LPG is far safer than petrol in a servicing environment so the argument for Health and Safety falls at the first hurdle...

The main problem with the single point system has been seen above, it gives a poor mixture that can result in carbon build up, the engine above was obviously set up rich and as such lasted well, if the single point system is set up lean it will wreck an engine very quickly. The problems seen in the early days of LPG are now a thing of the past, the modern systems ensure the engine gets the correct mixture and engines that are prone to valve wear will get an upper cylinder lubrication system or flash lube as its more commonly known, this drip feeds lubricant to the inlet manifold to lube the valves.

Try showing the above letter from Lexus to your local garage and ask for their comments.

Good Luck

Pete

Pete

I do not live to far from you and i am looking to have my RX300 converted, is there anybody in the area that you would reccomend.

Thanks

Hi I have just had my LS430 '51' 75000 miles converted. I had the same guy that converted my Honda Legend, ( my previous car )and did 65000 miles on gas with no problems (single point ) I can recommend this guy, having three generations of converters in his family. If anyone is interested he is at M6 J33. If you contact me I can give you specific details.
Regards Jon

PM sent

Pete

Hi all

Just a quick update, I've now done over 2000 miles with the conversion and it is returning around 19.5 mpg on LPG, the equivalent of around 24-25 on petrol. I can get 65ltrs of LPG in the tank so the range is about 280 miles, not too bad at all.

The car is running very well and actually feels stronger on LPG, maybe the ecu is allowing more ignition advance. LPG is around 110 octain so you can run with more ignition advance than petrol thus getting a bit more power....

Have also found a Calor Gas place near me that does LPG for 47p per ltr so I'm getting the equivalent of about 43mpg....

Pete

just a quick note here on the servicing side you chaps where talking about.Any garage(main dealer or not)can service a car with l.p.g conversion,YOU CAN NOT SERVICE THE L.P.G SIDE OF THE SYSYTEM WITH OUT THE CORRECT QUAILFICATIONS.Having worked for Lexus and Toyota for years i can tell you that we used to service them all the time,having said that we would not get involved in any diagnoistic work(miss-fires,ect).All the courses and training i went on,when l.p.g was ever disscussed it was a very gray area,Lexus and Toyota use hybird as there system.From what i gathered if a manufacturer does not produce a car with the system allready then they will not condone the product.The question i allways ask myself is how do people know if it was the L.P.G conversion that caused engine problems when the L.P.G tends to be fitted to high millage cars,what problems did the engine have before? and would the same issuse still happened if there was no L.P.G install?
Its still a gray area for me,seems to be a bit like marmite,you love it or hate it!!!
Not to sure what it does to to the resale value of the car,do people want L.P.G cars more or leave alone and buy the petrol only version?????
See back to the gray area again.

Hi

Believe it or not there are no regulations regarding servicing or installing LPG on any vehicle in the UK, you can do what you want as badly as you like with as many leeks and faults as you can get and you are certainly not committing any offence or breaking any rules. You do not need qualifications to work on LPG, it is not covered by Corgi or any of the "building" based legislation. You would have great difficulty in insuring your car without an LPGA certificate though.

The LPG industry is self regulated by the LPGA and its fitters have to be trained, and fit the system to a required standard, this standard is stricter than any other country worldwide and is based on safety.

Like all manufacturers Lexus do not like you modifying their cars, but they do take a rather more grown up approach than most car companies, they will service your car and uphold warrantee issues if not as a result of the LPG install, I take it this would be their decision, yes there are areas that would be difficult to decide what caused the fault but from what I have seen and heard Lexus are fairly good at keeping the customer happy and would do all they can.

Resale values of LPG cars are always more than petrol cars, I have had numerous LPG converted cars and always sold them for more than the going rate for petrol cars, indeed there are several companies who specialise in selling only LPG converted cars and they always sell for a premium. I would expect my 2001 LS430 to go for £500-£750 more with the top of the range injection kit.

I agree LPG is a marmite issue though and if you go that route you have to expect some compromise for 40+mpg...

Pete

all very good and interesting points.From a warranty point Lexus will not up hold any parts that l.p.g have been in contact with,i.e valves,pistons,head gaskett ect.It is in your warranty hand book,but like you said they are very very good in customer care(there aim to be no1 by 2010)so they will always try and help.The servicing of the l.p.g i can not see many garages getting involved with.if any,Lexus do not condone the system,you can not check the system properly with out the right equipment and you have to guaranty all your work.It is some thing i have often toyed with but never undertaken.Knowing my luck ill bite the bullett and have the work done,and the goverment with take the tax up on l.p.g!!!!!!!

Hi

Yeah I imagined that would be the case with the warrantee but mine hasn't got one any more so I have to pay for it all anyway. I used to do a lot of services on LPG systems and they are dead easy any mechanic can do it, just changing filters in the vaporizer and sometimes they have one near the tank. It always amazed me how dirty they got with just having gas running through them, I guess it’s quite dirty!!! Then it’s just a full check of all LPG bits to ensure they are secure, not leaking and working OK. If the system is running OK then they don't need re setting up with a computer, a good check is emissions and an OBD11 reader to check if the lambda is cycling and that the fuel trims are not miles out.

The LPGA made the same point you make about the tax hike and the fact that it was ruining the industry so the government now have a rolling three year promise to not raise the duty any more than petrol, so the difference stays the same.

Pete

you make very sound points,and a lot of food for thought.I am in the situation again now where i am thinking of l.p.g or a second car for work,i have just moved from working for toyota/lexus to b.m.w and now have 45 miles more a day.For 2k i could buy a derv and save fuel and miles on my lexus,or get the lexus put on gas for 2k.Talking to you has just made my choice harder!!!

erm I think your signature needs a smaller Picture Andy

What a great and informative thread this is. The professionalism and care taken with this LPG conversion is amazing. It is just a pity that this dreadful Government seems hell bent on taxing Lexus owners out of existence - the current price of petrol is the highest in Europe and Brown blames the Sheiks, even though most of the cost is taxes.

Just read this topic, and am thinking on LPG myself.

A mate has just had a GS430 done, and he is more of a petrol head than me.

He used someone advertising on e-bay (based in Cardiff £1500 all in). I have not had a chance to drive his to form an opinion, (and won't be seeing him 'til August).

So you should be able to get a good system done for less than £2K, and an old Lexus engine is still going to me more reliable with LPG than most of yer average engines.

I have a number of friends who have ditched their Range Rovers as the LPG systems kept blowing gaskets, so I take a view a Jap engine will be very well engineered, and the higher spec required for LPG not a problem.

I also guess if you have problems, always best to take it back to where it was fitted.

At work at the mo, and the details of the guys in Cardiff on home computer, so if I remember I will try and post up their details in next few days

You can get LPG systems starting at around £1300 for an 8 cylinder injection kit, as with most things in life you get what you pay for, cheaper kits are just that, the ecu's use cheap parts, the vaporiser is cheaply made and the injectors are poor quality and erratic at fuel delivery.

Think of it like buying an old Lada or a Lexus, the Lexus will keep going for a lot longer than the Lada, but at the start they will both be as designed and work well....

If you do average miles then you will get away with a middle price range kit. They will set up correctly and last for quite some time. If you do high miles or want reliability then you have to pay for it.

Most Range Rovers are done on the cheap with very cheap systems. This usually results in the engine running lean and hot and eventually blowing a heat gasket, this is also in part because of the ridiculous inlet manifold on the Rover V8, the mixtures are poor across the cylinders on petrol so LPG hasn't a chance....

The Lexus V8 will run for hundreds of thousands of miles on LPG with no adverse effect if the system is set up and keeps running properly...

As I have stressed before, anyone can fit an LPG system and make it work, your car will run fine as you drive away but if it is not set up correctly then your engine will be suffering and you will have problems further on, the garage who fitted it will deny all responsibility and you are left with a large bill and you will hate LPG forever.

So if you want your Lexus to live long and prosper then buy a decent system, get it fitted by an experienced fitter who knows the car and the system and ensure it is set up correctly...

Buy a "cheap" conversion and that is exactly what you get....

All these ones on eBay advertising a "one day turnaround" cannot possibly do a proper job in that time, it would take a minimum of two days to fit the system correctly and then at least two hours to set it up..

So as always..... Buyer beware...

Pete

Hello Again Pete

I've now had the Lexus for a month and really enjoying it. Its got a PRINS system with a 95ltr (water capacity) STAKO Toriadal tank. I find that I get about 200 miles from having 4 green lights on the indicator to the red going on- but when I fill it up I can get about 48 ltrs in so I'm getting a red light with, in theory, about half a tank being used. Is this your experience too? Do these tanks actually hold the water capacity of LPG because I read something about thermal expansion of the LPG somewhere so my guess is that the tank only holds 2/3 capacity of it's water capacity. A full tank would therefore hold somewhere just over 60ltr on a 95ltr tank.

Am I right in thinking this or do you think my indicator needs looking at?!

Leigh

Sounds about right to me. The red light on mine covers at least a third of a tank! I use the trip counter instead - above 230 miles and I know I'm on borrowed time.
My 75 litre tank holds 60 litres, I'd expect you to get about 75 in yours.

Leigh

The guages on these tanks are very unreliable, they work on a float connected to a magnet that drags a variable resister to register the contents, what you have to remember is that when it hits red it is indicating that there is LESS than 1/4 of a tank + reserve.

It is perfectly OK to let the car run out of LPG, when this happens the petrol/LPG switch will beep at you to tell you it has switched to petrol, press the button and it will stop and stay on petrol,you can then fill up with LPG. You will not damage anything by doing this. Do it a few times with a full tank and you will then have an idea of how far you can go.

Your tank should fill to 80% of its water volume with LPG so as exobex says you should get about 75ltrs. This is not exact though, when its cold you will get more in and when the garage has a freshly filled tank you will get more in.... most vary by up to 10 ltrs from the "ideal 80%"

So just try the fill up to switch to petrol and note how many miles and away you go.

Is your boot floor flat because if it is then you haven't got a 95ltr tank, mine at 83ltrs and needed panel beating to fit.... If you take the top of the alloy box in the boot, the capacity is stamped into the tank, along with lots of other numbers but you will find it there somewhere....

Good Luck

Pete

Thanks for that guys.

I'm going by what the certificate says when I say 95ltrs. (Incidentally- £45 for a replacement as the garage had never seen it). I'll have a proper look when I get round to it. The spare tyre is still hanging around in the boot and I keep meaning to take it out. A friend told me that legally you have to have the means to take care of a flat tyre (is this true??) so I thought I'd get hold of some foam.

I'll try running the tank to empty on Saturday when I do a run down to Gatwick just to see what kind of mileage I get on a motorway run. I was told not to run out of gas when I bought the car but I don't think they knew a lot about lpg. I'll be interested to see how many miles I can get.

Leigh

Leigh

You do not have to have the means to replace or fix a flat tyre, If you have a spare tyre in the car it must be legal but there is no need to carry one, so stick it in the garage. Lots of sports car these days come from the factory without spare tyres and all Vauxhalls with factory fit LPG don't have spares either.

If you have the Prins VSI (injection) system then there is no problems with running out of LPG, if you have the old Prins AFS system (single point) then yes if you run out you could get a backfire, but not very likely...

Do you know what system yours is ?

Pete

Hi Haylands et al,

I've just bought a 2002 LS430 with 143,000 miles (also Canterbury blue) and have booked to have it converted to the PRINS VSI in a couple of weeks so I've read this topic with interest. By the way, is there a later thread on this topic?

Thanks so much for your excellent commentary on the installation, it will help in the event of any queries that might arise during my installation. When I visited the installer, having checked him out first, I was very glad to see that he had another LS430 on his ramp and that he'd just about finished it. He was able to run through what he'd done and explain how he'd overcome the various hurdles involved. Great to know that he doesn't have to re-invent the wheel when he does mine!

I was interested in what you said about aluminium engines. Does this mean that the engine will be adversely affected by the LPG, and, if so, are there any precautions you think we neeed to take - eg. driving gently, special engine oil, more frequent oil changes, some additive? In my line of work I intend to take it well past 500,000 miles so I'd like to be prepared.

Regards,

Mike

Mike

Hi and welcome to the club... There are NO issues with aluminium engines and LPG, someone had heard that LPG burns hotter than petrol and this would damage the engine but the difference is miniscule.

You do not have to do anything special to drive on LPG, service as you would on petrol, you do have to make sure the high tension side of the ignition is in good condition, any faults will show as a misfire on LPG before it will on petrol.

You will notice that your oil stays cleaner on LPG, but this does not mean you don't have to change it, it will still get worn out.... its just clean and worn out though.....

Had mine MOT'd last week, passed OK and the tester tested the emissions on LPG.... result C02 0.00% Hydrocarbons 7 ppm lambda 1.003 ... that’s very good and shows the LPG system is set up correctly.

Good luck with the install, mine went well and is still fine some 8000miles later.

Any other questions please ask...

Pete

Thanks Pete!

I had my 430 converted and have a complete disaster on my hands I have been without the car for several weeks now. The conversion went well but then it seems the ECU packed in after a hundred miles - the car started missing and reported a fault - the VSC light came on - also the remote entry system stopped working. The car ended up at a Lexus dealer who says it needs a new ECU, a new engine bay wiring loom and two new Oxygen sensors - the bill being 50% of the cars value - don't worry I'm not paying.

The ECU was changed (£1,000) but the problem persists - the gas system has been completely disconnected and the plan is to get it working on petrol. The fault appears when the car has warmed up - I cannot see how the wiring loom will fail as it get warm - the ECU yes. The Lamba sensors are not old max 25K miles each, there are no air leaks. It will be time for the lawyer soon.

The LPG system is from BRC.

Any ideas?

I would guess if the company that fitted the conversion, had hacked into any part of the loom then Lexus would replace it as a matter of course. the lexus fault diagnostic equipment will not be looking for external modifications.

but shouldn't BRC be trying to fix it for you, as they will just say Lexus screwed it up?

Hi Brendan,

I am sorry to hear your awful tale, you must be gutted.

Can you tell us who the installer was? Presumably they were recommended by other satisfied customers; preferably LS 430 customers.

If you don't get any sense out of the installer (BRC are the equipment manufacturer btw Matrixabc) you ought to try visiting BPV Servicing in Slough. Although they are a small business and their website is still under construction they have been going a long time and have an excellent track record for sorting out problems created by other installers. Speak to Barry. He has just finished my LS430 and a couple of weeks ago he did another one.

The Lexus diagnostic system is apparently very fond of reporting the Lambda sensors as "out of order". I'd be inclined to check myself. I've recently been working on a running problem with my Ford Scorpio. When most other options failed, I thought I might as well change my one and only Lambda sensor as it had been on the car since new 315,000 miles ago (yes 315,000!). No joy though, the old sensor was still working fine! At least they only cost £50 on a Scorpio.

Regards,

Mike

OMG that is terrible.... its one of the reasons I thought long and hard about a conversion and decided on the Prins, and fitting it myself. The BRC system is a widely used one and is claimed to be the best selling in Europe, the only thing I have against it is that they don't produce a "kit" for conversion but supply all the separate parts and leave it up to the installer to decide what is needed. It sounds to me as though the installer has made an error in wiring in the kit, if fitted correctly there is no way it can damage the car as it should only be "stealing" information from the car and using this to determine the correct amount of lpg to use.

I hope the installer is LPGA approved and that they are accepting liability.

I am not an electrician but I have heard of soldered joints failing when the heat up so maybe this is the problem, I can't see how it can have damaged the lambda sensors, I would imagine that this is a fault showing because of other faults (if you understand what I mean)

Anyway good luck with it, please let us know what happens.

Pete

hi.my 2002 430 has done 120k since i had a prins system fitted.although i use an independent specialist, my local dealer in Reading(xcellent) have never refused to work on it if required.they have 6 or 7 lpg cars that come in often.

very good thread.looks just my conversion(prins also) and still going well(touch wood) 120k later!!

An update on the disaster - still a disaster.

My installer is a good guy and has accepted liability so his insurance company is involved and I am talking to them. Some good news is the same company converted another 430 after mine with no probs.

The installers insurance company has employed a consulatant engineer ( I am an eletronics engineer with 30 years experience myself) who has been in touch with me and is a good chap - he is keen to get this fixed. The ECU was changed - no fix, the oxygen sensors have been changed - fix. The dealer now wants to change the engine bay wiring loom - the insuranve company are not keen because it will cost £3500 and cannot see how this will fix a fault that only develops when the engine has warmed up.
The Lexus dealer does not seem to understand how the system works and only wants to change all the parts till the car is back in spec as they see it. I asked them what they will do if the car still has a problem after thay had changed all the bits they want to - they did not have an answer.

Any good ideas are welcome - bad ones too if they work.
Names withheld to protect the guilty - when it's all fixed we shall see. It will be lawyer time soon.

My conversion went ahead without a hitch although the installer did mention that he wants it back in a couple of months to install a new automatic lubrication system that should be available soon.

I've done around 1,000 miles in the first week with no problems. The only thing I've noticed is a noise which I think is the injectors as it stops when I switch to petrol. I don't mind hearing them under the bonnet but I don't want to hear them in the cabin. Does anyone else (on gas) have this? It is only really obvious when going very slowly or when stationary as the road noise drowns it out when moving at speed.

I'd like to get rid of it as it's obvious and annoying when you can detect it and clearly will be adding to the total noise levels when you can't.

I think, in my case, that the injector rails have been fixed to a part of the car with a steel plate and, as such, the vigorous clicking of the injectors is being transmitted to the rest of the car as faithfully as a note plucked on a guitar; only in my case it's like Jimmy Hendrix playing alongside Erik Satie.

My plan is to introduce some nylon washers into the equation. Do you think this would help? Does anyone have any other ideas?

Thanks

Mike

PS This car is lovely!!

Hi
Sorry to hear you are still having problems... I take it the car is still misfiring when hot... just a thought, how did they install the injectors in the inlet manifold, has this caused a leak or has swarf entered the engine and is sat on a valve seat, I have heard of this in the past, when cold the ecu will richen the mixture and could mask the fault, when hot... misfire...

What about the ecu wiring, how has the gas system been removed? Have all the wires been returned to the correct place?

I wouldn't worry too much about it though, if the insurance company is paying then it will get sorted, what does their engineer want to do?....

Good Luck with it all, please keep us updated

Pete



Mike

You are correct, it will be the injectors, they should be mounted with rubber mounts, not direct to a metal bar. I always used a metal bar to the engine then two rubber mounts to the injectors, this insulates the engine from any noise.

If they are fitted with rubber mounts it maybe because they are touching something else under the bonnet, if they have been squeezed in somewhere this is very likely.

If they are fitted with rubber mounts and not touching anything alse it could be the route of the gas pipe to the injector rails, if this is fixed to the bulkhead it will amplify the noise straight into the cabin.

It's a pretty straightforward fix. I don't think nylon washers will help, the rubber mounts are a solid chunk of rubber about 10mm long with a threaded bar moulded to each end, a bit like an exhaust mounting but much smaller.

What system have you had fitted, most come with some type of rubber mount?

If you don't get any luck with getting some, let me know, I'm coming to see my mother who lives in Marlow in a couple of weeks and can drop you some off....

Pete

P.S. Just a note for anyone reading this and thinking of getting a conversion, the above stories emphasize how important it is to use an experienced fitter, as I have stated in the past just about any mechanic can make a car run on gas, how well and without causing damage to the car is another matter. Always ask to speak to satisfied customers with similar vehicles and always check they have insurance, the above two problems have occurred with professional installers who will make sure they get sorted but there are a lot of converters out there who will wash their hands of it and leave you to sort the problems out.

After all you are fitting a whole new fuel system to the car, it has to be done right.

Mike

Sorry, remembered your old post, you have a Prins system as well, the injectors are very good but they are noisey, still, if they use the rubber mounts all will be quiet, I can't hear mine at all inside the car..... as I said if you need some let me know.

Pete

Thanks Pete, I'm going to have a good look in the next couple of days; I'll let you know how it goes. Glad to hear I'm on the right track.

Regards,

Mike

Hi Pete,

Ok, well the rubber pipes seem to be routed ok although I've added a few anti-chafing precautions here and there.

The injector rails however are, as I suspected mounted with a short strip of mild steel onto what I assume is part of the inlet manifold. There is no attempt at any damping of the vibrations. Here and here are a couple of images of either end of the strip. The other bank is similar. Can you see how I could arrange this better?

Thanks.

Mike

PS Sorry, this sounds like I haven't read your post properly. The rubber chunk with steel on either end sounds good. The only thing I'm concerned about is that the strips of steel are very short already. Do the "rubber" ones come in different lengths and shapes; or failing that, are they bendable? Thx!

P.M. sent to Mike

This is the kind of rubber mount I was talking about



Pete

Thanks for your help Pete, I hadn't thought that it might be the vapouriser. I put my ear to the front of the o/s front wheel arch void where the vapouriser was installed and got Mrs. F. to switch the gas on as I listened. Sure enough, it was like a little guy with a hammer was living in there and we'd just woken him up - bang, bang, bang, bang, bang!

I've got a fairly quiet day tomorrow so, weather permitting, I'll get the covers off and see how it's attached.

Those rubber mounting things look like they're just the job; where can one purchase such items would you say?

Thanks again!

Mike

Mike

Sorry missed the above...

Vaporisers are usually solidly mounted, I would check the gas hoses from it and also the gas feed pipe from the tank, if they have used plastic covered copper (some use plastic pipe now) then this is very good at transferring noise to the body shell. I would check all the pipes and hoses from the vaporiser and the injector packs to see if any are touching or fixed to the body and start there. If not then what is the vaporiser mounted to? if it’s just a single skinned inner wing then it maybe this, we usually tried to fix them to mounting points for other items as these are usually strengthened and don't vibrate so much...

Good Luck

Pete

[quote name='zantiaboxer' date='Apr 3 2008, 04:44 AM' post='527348']
[quote name='Haylands' post='523342' date='Mar 21 2008, 11:58 PM']Hi all

Finally got the car back from the repairers, took a week longer than expected but the end result was very good, to recap a Discovery drove in the back so had a new bumper and boot lid, lights etc, they managed to straighten the rear panel. Then two days later a tile fell off the roof onto the bonnet so I had that repaired as well.....
Well that left only two days this week to do the LPG install, I wanted to do it before this weekend as we are off visiting and will do about 2000 miles next week....
Some may remember I promised to do a write up on the fitment of a top of the range LPG Prins Vapour Sequential Injection (VSI) kit to the LS
I used to work for an installer so I have used his premises and equipment for this, it’s so much easier when all the necessary tools are to hand.
I didn’t take as many pictures as I intended due to the time pressure but the following will give an idea of whats involved.

This is what we started with.... looks nice and smooth....



Hi, Thanks for the excellent post on your LPG instal. I am about to buy either a Lexus LX470 or LS430 (can't quite decide which one). & I will want to fit an LPG system to it. I have heard that the "newest" best system is a LIQUID- INJECTION system, as made by JTG & prob a few other Co's. The new LIQUID-INJECTION (sequential) Lpg systems are supposed to be even better than Vapor-Inj, & use about 10% Lpg fuel too. Did you go with the Prins Vapor-Inj because you are more familiar with installing these or could get it at a better price ? Otherwise what Brand & model Lpg system would you reccommend for the LS430 / LX470 ? (http://centralgaragecarcroft.co.uk website gives details on many Lpg brands & models too.). Thanks in advance for your help.

This is an update on the tapping noise I was getting from my gas installation. I took it back to the installer and we noticed that the filter/splitter unit (that goes between the vapouriser and the injectors) was simply bolted on to the metal frame of the engine compartment near to the radiator. We unbolted it and covered it with some sticky-backed rubber stuff and just left it suspended by it's hoses as it's very light.

The upshot is that 75% or so of the noise is gone - even with the heater blower off you can barely hear it now.

Problem solved.

Thanks for your help and advice with this Pete.

Regards,

Mike

Mike

I still think it will be a hose touching part of the bodyframe, how are the two hoses from the filter to the injectors routed, they should not really touch anything as they vibrate at a different rate to the engine because of the injector fireing (which is the noise you can hear) Mine is totally silent even with the aircon and seat blowers off. I'd try some foam on them wherever they get near something.

Pete