LPG Chimaera (Follow My Conversion)

[stevesprint]

ric355 said:

I would say either you're bothered about MPG or you're not, and a very high percentage of people who own large capacity V8s just aren't that bothered about it, otherwise they probably wouldn't have bought said V8s in the first place. Remember many people own cars like ours as weekend toys, so fuel savings are not the priority like they might be on a daily commute.

I total agree.

Although I will never add LPG to my Griff, I respect CoG’s tenacity & I enjoy learning from his meticulous posts about his achievements, especially the posts that are also relevant to petrol, like ignition maps and injectors. With CoG’s posts like the two at https://www.pistonheads.com/gassing/topic.asp?h=0&... he’s wasted on PHs and should write a book. I’m now looking forward to his next instalment .... “The Thor inlet manifold” .... Dun Dun Duuuuuuunnn, Dave, no pressure

One of my Griff friends followed the Chimp on Gas and was very surprised how quick it was.

[ChimpOnGas]

stevesprint said:

One of my Griff friends followed the Chimp on Gas and was very surprised how quick it was.

I know its hard for people to accept, but LPG doesn't mean slow

Another LPG myth busted right there

[motul1974]

Thor inlet manifold- that's the one I'm watching VERY closely too!

[ric355]

motul1974 said:

Thor inlet manifold- that's the one I'm watching VERY closely too!

I happened across some comments on the Thor manifold on this website a couple of weeks ago;

http://www.mez.co.uk/ms12-new.html

It's a long page but if you search for the word "Thor" on the page there is one section where it is mentioned twice.

[ChimpOnGas]

motul1974 said:

Well, I'm simply happy to know that there's another route to running my car in the future if the older petrol cars become an issue, so thanks for sharing your work. :-)

On the face of it the future of the internal combustion engine is bleak, the savior of classic cars will come in the form of a gas but it's not going to be LPG

There are currently two technologies fighting it out to replace the internal combustion engine:

1. Electric vehicles

2. Hydrogen fuel cell cars

In simple terms a hydrogen fuel cell uses hydrogen and a chemical reaction process to produce electricity, a hydrogen fuel cell is just an on board power generator for what is essentially an electric vehicle.

The interesting point is you dont necessarily need a hydrogen fuel cell to produce motive power from hydrogen, you can also burn it in an internal combustion engine. Whats even more interesting is the growth in hydrogen fuel cell cars on our roads is dicatating the number of fuel stations offering hydrogen must grow in response, so the availability of hydrogen is only going to improve.

Indeed two years ago the only hydrogen close to me was in Ealing, I can now buy hydrogen in many locations in and around London and across the south of England. The rise in hydrogen fuel cell cars will create a network of hydrogen stations that will rival anything we currently have for LPG, and those stations won't care if you are buying hydrogen to make electricity in your hydrogen fuel cell car... or burning it in your internal combustion engine .

The fossil fuels we currently burn in our internal combustion engines are all hydrocarbons and that includes LPG, they are all a mix of hydrogen atoms and carbon atoms which is why we refer to them as hydrocarbons. LPG is cleaner because it typically only contains three carbon atoms whereas petrol contains 4-12 carbon atoms (typically 7), diesel is even worse as it contains 12–20 carbon atoms (typically 15). This is why diesels dirty their oil almost instantly after an oil change, it's also why the oil on my LPG Chimaera stays as clean as new for 10,000 miles or more, and my combustion chambers remain spotless compared with a Chimaera burning petrol .

Pure hydrogen as the name suggests contains zero carbon atoms, it is therefor not a hydrocarbon like the fossil fuels we currently burn, when you burn pure hydrogen in an internal combustion engine the only byproduct is pure H2O (water), effectively any internal combustion engine burning pure hydrogen instantly becomes a zero emissions vehicle. As the network of hydrogen fuel stations grow to support hydrogen fuel cell cars I expect a similar decline in LPG stations, my response will be to convert my Chimaera to burn hydrogen instead of LPG.

Essentially by a lucky twist of fate the increasing availability of hydrogen because of the rise in hydrogen fuel cell cars becomes the savior of all internal combustion engined vehicles, this will be particularly relevant to the only internal combustion engined vehicles that will remain... IE classic cars . In ten years time nobody other than classic car owners will have an internal combustion engined car, and there will be intense pressure on these classic car enthusiasts to do something about how dirty they are.

Converting an internal combustion engine to burn hydrogen is much the same as converting it to run on LPG or compressed natural gas (CNG). Basically like LPG & CNG you can convert any internal combustion engine to run on hydrogen, the key difference between LPG and Hydrogen is the pressure the hydrogen pump delivers the fuel at and therefor the pressure you need to store in at in the car.

All these gaseous fuels (LPG, CNG, Hydrogen) need to be compressed to turn them into their liquid state or you'd need a huge balloon on top of the car just to travel 50 miles, LPG becomes a liquid when you compress the gas between 32 - 50psi so it's typically delivered at the pump and stored in the tanks at 60psi.

That's a very low pressure when you compare it with CNG, but get ready folks, hydrogen needs to be stored in your car at an insane 5,000psi to ensure it remains a liquid. This means you need special composite tanks, my steel LPG tanks just wouldn't cut it,you also need a vaporiser that's capable of bring the pressure down from 5,000psi to 125psi before it's delivered to the injectors. To put the vaporiser element into perspective my LPG vaporiser only needs to drop the pressure from 60psi to 28psi.

Another difference is LPG in it's gaseous state caries 18% less calorific value than petrol which is why I designed my conversion to carry 18% more of the stuff so I can still achieve the standard petrol Chimaera's range of 300 miles. However, hydrogen in it's gaseous state caries 30% less calorific value than petrol so not only would you need special composite tanks that cans sustain a whopping 5,000psi they need to be big too to achieve your range, for the 300 mile you'd need to carry 17 gallons of the stuff which is going to take up a lot of boot space.

The answer to the calorific value issue is to inject the gas as a liquid not a gas, both LPG and hydrogen in their liquid state have a greater calorific value than petrol so you'd actually need to carry less of the stuff, 11 gallons of hydrogen injected as a liquid would easily give you your 300 miles and because your keeping it as a liquid right up to the injector you clearly dont need a vaporiser which obviously eliminates the pressure drop requirement in a stroke.

So you see, LPG is just a stop gap, the future for the internal combustion engine (and that really just means classic cars) is super high pressure liquid hydrogen injection, and thanks to the rise hydrogen fuel cell cars we will be able to buy our hydrogen everywhere. Our cars will immediately become zero emission vehicles, restriction on their use will be lifted, and the glorious sound of the mighty V8 will remain with us forever .

LPG is a great stop gap, but the truth is hydrogen is what we'll all be burning in our classics in 10-20 years time

More about burning pure hydrogen in an internal combustion engine here....

https://www1.eere.energy.gov/hydrogenandfuelcells/...

[ChimpOnGas]

What people dont realise is innovators like Rouch have been running internal combustion engines on pure hydrogen for years.

https://www.youtube.com/watch?v=80xP7XSDDgs

https://newatlas.com/hydrogen-conversion-for-petro...

And while they are focusing on local delivery vans, they also have a Ford GT40 running on pure hydrogen. The technology to run an internal combustion engine is well understood and has been around for years, most importantly the infrastructure to make the fuel a practical proposition is already here too.

Only a few weeks ago I pulled into the motorway services on the M40 at Beaconsfield to buy some LPG only to find it wasn't available as there was some tank installation work going on, I asked the attendant if they were updating their LPG tanks and he said no "we are installing a hydrogen pump".

Of course this hydrogen infrastructure is not being created for internal combustion engined cars that burn hydrogen, it's there for hydrogen fuel cell cars, currently in the UK you can buy two different hydrogen fuel cell cars:

• Hyundai's ix35

• Toyota Mirai

It's really just a lucky twist of fate you can also burn hydrogen in an internal combustion engine, so we should all be getting behind hydrogen fuel cell cars as they will save our classic fuel burners.

The challenge for hydrogen fuel cell cars is the extremely rapid advances in battery technology, currently hydrogen fuel cell cars have their place because it's relatively straightforward to carry sufficient hydrogen in a car to allow it travel 300 miles or more, you can also completely fill a hydrogen fuel cell car with 300 miles of fuel in 3 just minutes. Currently the best electric cars take 30 minutes to speed charge to 80% which at best means only 180 miles, but in just five years time because charging and battery technology is progressing so quickly you'll be able to add a 300 mile charge of electricity in just 5 minutes.

At which point the current fill speed and range advantages of the hydrogen will be completely lost, hydrogen fuel cell cars will become the Betamax of the alternative fuel world and everyone will adopt an electric car instead, the hydrogen stations will disappear and us internal combustion lovers and classic car owners will be back to square one. This is a real shame but I could easily be wrong with my pessimistic prediction for hydrogen as I dont posses a crystal ball, I genuinely hope hydrogen fuel cell cars catch on as I will definitively convert my LPG TVR to run on hydrogen if the infrastructure remains.

Actually if you look at the UK hydrogen infrastructure map today, it's already a surprisingly comprehensive picture, and the roll out plans to improve it are very aggressive and well published. In March 2017 the government created a £23 million fund to accelerate the take up of hydrogen vehicles and roll out more cutting-edge infrastructure.

Here's how the hydrogen infrastructure looked just 2/3 years ago...



And here's what it looks like now in the first quarter of 2018...



So maybe hydrogen is here to stay after all?

[ChimpOnGas]

For anyone still wondering why I continue to persevere with LPG after more than five years since I started all this , the following simple calculations should help.

Here's yesterday's example using my local Sainsburys forecourt prices:

Petrol = £5.72 per imperial gallon (cheapest petrol in my area)

LPG = £2.45 per imperial gallon (at the same station)

£5.72 / £2.45 = 2.334 (the multiplier)

So to find out the petrol consumption I'd need to achieve in my TVR to match what I achieve when running the car on LPG I simply take my true LPG consumption of 21mpg and times it by the above multiplier.....

21mpg X 2.334 = 49.01mpg..... 'Petrol Cost Equivalent'

Not bad for a 150mph 4.0 litre V8 TVR Chimaera that gets from rest to 60mph in five seconds



The above is the fairest way to demonstrate my petrol cost equivalent MPG figure as it compares the price of the two different fuels on the same day at the same station.

However, if I run the same calculation using the average petrol price local to me which is a painful £6.00 a gallon, the results are even better.

Petrol = £6.00 per imperial gallon (average in my area)

LPG = £2.45 per imperial gallon

£6.00 / £2.45 = 2.448 (multiplier)

21mpg X 2.448 = 51.41mpg..... 'Petrol Cost Equivalent'

The above demonstrates what actually really matters is the percentage cost difference between the two fuels, this is because on any given day if I wasn't running on LPG I'd be forced to run my TVR on petrol like everyone else does. So it's not actually the displayed forecourt price of the fuels that counts, the important element is actually the price gap between the two fuels at the same station on the same day.

Quite simply if I wasn't buying their LPG I'd be forced to buy their 95Ron petrol instead.... or I'd be going nowhere fast!.

Transforming a thirsty 4.0 litre TVR Chimaera that averaged 23mpg on petrol and turning to a 50mpg vehicle is quite literally game changing, and as petrol prices continue to climb LPG becomes an even more appealing option

I could never go back to petrol, the thought of paying to fuel a petrol only Chimaera actually scares the life out of me, this why I continue with the Canems Duel Fuel engine management system.

[spitfire4v8]

It is ideal for high mileage users, and the conversion is a very interesting technical development, I don't think anyone would argue with that. But how many people have taken the idea and run with it? ie how many other TVRs are running lpg?

ps do you ever get the kiosk people on the tannoy saying you're filling up at the wrong pump?

[NuddyRap]

When I was doing a mega mileage commute, I had a fuel bill of around £1000 per month.

I did the maths, bought a cheap LPG car and within 10 months I had bought a house using the fuel savings as my deposit. I no longer commute so far, meaning that the saving vs a diesel isn't anywhere near as impressive.

Using an LPG car was genuinely life changing for me and I completely understand why you would convert a Chimaera. There are hundreds of LPG RV8 Range Rovers etc around were it not for the fact that I've just spent way too much refurbing my car, I'd seriously be looking in to a Chimaera on gas as a daily. Your posts have helped firm that up as a goal for me.

I'm not quite so sure I'd want to convert my Cerb, despite a deep understanding of LPG myself, given what I've just spent on the engine.

I'm curious about the injection of liquid hydrogen and how to manage the cold temperatures caused by the rapid expansion of very dense hydrogen when it leaves the injectors. A piston with a few rings around it wouldn't be able to keep it compressed to the same level as a massive tank to control the pressure therefore the temperature. I'd love to see a thermodynamics model of it.

[ChimpOnGas]

spitfire4v8 said:

It is ideal for high mileage users, and the conversion is a very interesting technical development, I don't think anyone would argue with that. But how many people have taken the idea and run with it? ie how many other TVRs are running lpg?

Lol, all good points , I put the slow take up down to fear and ignorance

I guess it's a long term ownership and an investing in the future thing, the project was also a nice way for me to demonstrate how you can take an already great sports car that I view as an 'Improved Classic' and make it even more practical to own, delivering a 45-50mpg Chimaera saw to that nicely.

I still don't get why people pay £30-£40k for a Cobra replica or £10-£15k for an asthmatic MGB, when they could quite easily have the far superior TVR for MGB money.... or save a small fortunate on that Cobra replica?

spitfire4v8 said:

ps do you ever get the kiosk people on the tannoy saying you're filling up at the wrong pump?

Yes, once, that's it.

However, I'm approached when filling up by the general public quite often, it usually starts an interesting chat, this happened only last Wednesday at the Murco in Stone Henge. The guy was really interested in the car and as it turned out he was restoring an E-Type so we had a really nice car chat that probably never would have happened if he didn't see me filling with gas. He was filling his Range Rover with LPG at the time so clearly a smart cookie, most people that stop for a chat are either amazed petrol heads or LPG converts who totally get what I've done and why I did it.

On that one occasion an attendant got involved they didn't shout over the Tannoy, they simply shut the LPG pump off when they saw me apparently filling my boot with gas, I went in and had a chat and the woman who apologised profusely claiming she just thought I wall filling my boot with gas and she put the pump back on immediately after that. But this has only happened once and I have to say when the car was on petrol only it happened to me twice, at this point I should explain I used the original TVR petrol fill point to mount my LPG filler
















See, another area where the car is exactly the same on gas as it is on petrol

[ChimpOnGas]

NuddyRap said:

I'm curious about the injection of liquid hydrogen and how to manage the cold temperatures caused by the rapid expansion of very dense hydrogen when it leaves the injectors. A piston with a few rings around it wouldn't be able to keep it compressed to the same level as a massive tank to control the pressure therefore the temperature. I'd love to see a thermodynamics model of it.

BMW proved the hydrogen internal combustion engine works well way back in the 1990's, they had a fleet 5 series BMs running on the stuff for years and with excellent results.In the end they dropped the technology because the hydrogen infrastructure just wasn't there at the time, but this is changing now as hydrogen fuel cell cars (which work differently BTW) become more and more common.

However, the truth is there are real world challenges with hydrogen that go way beyond the infrastructure issue that forced BMW into giving up, not least the huge pressures needed to get hydrogen to turn into a liquid. You need some 5,000 psi to do this which means seriously strong carbon fiber tanks and super burst proof fuel lines, Hydrogen also has a lower calorific value than even LPG in its gaseous state. So you've got to carry at least 30% more of the stuff than petrol just to cover the same distance, like LPG you've also need a further 20% of tank volume just to allow for thermal expansion or you're going to have an exciting old time when the sun comes out!



Suddenly if you're planning to run your car on hydrogen you're looking to accommodate some very big and expensive tanks just to enjoy the same fuel range as the petrol only car you're converting, this is not to be underestimated as it's highly likely the real estate simply won't be available in a car that was originally designed to run on petrol.

Compare this huge 5,000 psi pressure with the far more manageable 177psi it takes to turn LPG (a butane/propane mix) from it's natural gaseous state into a liquid and you can see the challenge is way less than it is with hydrogen. LPG in it's gaseous state also has a lower calorific value than petrol but only by roughly 18%, so it stands to reason you need 18% more of the stuff to keep the car's petrol range, this again is a far easier challenge than accommodating the 30% more hydrogen you would need to achieve the same result.

It's a shame really as unlike all the different types of hydrocarbons we currently burn in road vehicles (LPG included) pure hydrogen contains no carbon atoms at all, so the only thing that comes out of the exhaust when you burn the stuff in an internal combustion engine is pure H2o. This zero carbon burn is actually used in the latest engine cleaning technology where the engine is forced to run at idle on pure hydrogen which completely cleans the valves, piston crowns and combustion chambers.

http://carproductstested.com/cool-car-products/car...

The system really does work, but as you'll be immediately leave running on petrol or diesel again you'll need to repeat the process every 10,000 miles or so or all that carbon will soon build up again.

The best alternative fuel solution for older petrol cars and classics at the moment is not hydrogen or even a gaseous LPG system like mine, what you really want is liquid LPG injection because in it's liquid state LPG actually has a higher calorific value that petrol. It's also an excellent solution for forced induction as LPG boils at minus 42c the moment you release it at atmospheric pressure, this super cools the hot incoming air charge from the compressor (supercharger or turbo) effectively giving you the most compact intercooler ever as it takes up zero space, it's also completely free intercooling that comes gratis with every cheap as chips £0.56p litre of gas you buy at the 1,000 or so LPG pumps already strategically spread across the whole of the UK for your convenience.

With my gaseous LPG injection system I'm actually throwing all this free super cooling energy away which is absolutely criminal if you think about it, I use my hot coolant to absorb all that lovely cool energy as the system literally fights itself to keep my vaporiser from freezing up. Liquid LPG injection is here right now, actually its been around and working reliably for some 10 years or more, it's probably the way I'll end up going at some point and what a nice partner it would make with an SC-Power kit or a turbo install

Gas is good, but its potentially way better if you can reliably introduce it into the engine in it's liquid state ...

I've chosen to keep things simple by sticking with a well managed gaseous system for now, I'm using proven components like trusted LPG injectors and vaporisers,,, this is simply because for me, reliability is king!

[Teetertank]

ChimpOnGas said:

Just the all-new TECH-YETI injector rail Alun, the latest thing in LPG injectors designed for use in extremely low temperatures.

Hi Dave,

Great to see your gassing developments on the Chimp.

Did you fit the Tech-Yeti injectors yet? Am curious to know how you find them and if they are a noticeable improvement over the Hannas?

I'm looking at assembling a new LPG kit and both the injector models you reference are in my short list.

Cheers.

[ChimpOnGas]

Teetertank said:

Hi Dave,

Great to see your gassing developments on the Chimp.

Did you fit the Tech-Yeti injectors yet? Am curious to know how you find them and if they are a noticeable improvement over the Hannas?

I'm looking at assembling a new LPG kit and both the injector models you reference are in my short list.

Cheers.

I haven't fitted them, I had some ECU issues and I didn't want the installer blaming the problem on me changing the injectors so I'm still running the Hanas which continue to work well, the Yestis remain unused in the box and are available if you're interested?

I did however change the reducer from the Prins VSI to a 'Magic 3 Power', which I can highly recommend, it gave noticeably better throttle response

[Teetertank]

Hi, ok thanks, was hoping you had some first hand experience with them as I read good things about Yeti performance but sone issues with reliability.

I'm interested in your spare injectors, though only need six and presumably you have two banks of four? If price is good could take them. Maybe message me direct as don't want to divert topic of this thread.

I was also looking into the Magic reducer you mention,
but surprised it can cope with your bhp requirements. It looks like it's small and natty. Was thinking about one of the higher powered KME golds but may reconsider the Magic if it really performs.

[ChimpOnGas]

Hi Hugo, on paper the Yeti injectors are very slightly faster than my Hanas but the truth is on a batched fired Rover V8 I'd be surprised if any meaningful difference could be detected. If they did deliver a benefit it would certainly only ever be at idle and in colder ambient temps, the reliability element is also a consideration, I'm not saying the Yetis are unreliable more that the Hanas are without question in this respect.

Reliability is absolutely the most important element of consideration for me, it overrides any small potential injector speed or cold weather benefits although these features are nice to have too.

There's no question the Hanas are supper proven and 100% reliable, my idle is also smooth as you like on the Hanna injectors, saying that the benefits however minor are nice to have so I may well end up fitting them all the same. The Barracuda injectors from Alex are well respected too, basically the Yetis were designed by the same guy for LPG Tech and are a direct competitor to Alex Barracudas, both have an internal fluoropolymer coating which stops them sticking when cold so both are likely to perform slightly better than the Hanas in the winter especially during the engine warmup phase.

The Magic 3 reducer I fitted is the 'Power' version not the standard model, and I run two outputs ie two separate hoses from the reducer each supplying each of the two banks of four injectors at a super stable 21psi even under high engine loads and aggressively driving. Like this the reducer is not remotely stretched on my 250hp Chimaera, I am reliably informed with the right injector nozzles I could push my Magic 3 Power reducer to 400hp without issue.

I'm super happy with it, the reducer gave noticeably better throttle response and better fuel economy too, there are definitely no issues with supply volume either as it easily copes with my 250hp and 260 ftl/bs, more info here:

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Edited by ChimpOnGas on Thursday 18th October 08:45

[ChimpOnGas]

Teetertank said:

ChimpOnGas said:

Just the all-new TECH-YETI injector rail Alun, the latest thing in LPG injectors designed for use in extremely low temperatures.

Hi Dave,

Great to see your gassing developments on the Chimp.

Did you fit the Tech-Yeti injectors yet? Am curious to know how you find them and if they are a noticeable improvement over the Hannas?

I'm looking at assembling a new LPG kit and both the injector models you reference are in my short list.

Cheers.

Hi Hugo,

I held off fitting Tech-Yeti injectors as I had yet another ECU failure, I was forced to reach out for support yet again but as I'd feared the installers who read these pages suggested I'd brought the issue on myself by fitting the Yetis (which I had not) so I was glad I never fitted them, in the end the ECU manufacturer stepped in and directly sent me a replacement ECU by post which solved the running problem but came with a new problem I'd never experienced wilh all the other ECUs I'd had before.

My latest replacement ECU came with a fault were the priming pulse would continually loop, this was a safety issue, sadly I faced quite an email battle before the installers agreed to take the car back which again included suggestions I may have somehow brought the issues on myself which I felt was very unfair given I had spent five patient years working my way through some four replacement ECUs that kept suffering LPG injector driver burn outs.

I kept these painful experiences that had left me stranded more than once (once in deepest France) from these pages as I wanted to work through the problems with the installers and ECU manufacturer, the system was showing how good it could be from day one so I very patiently tried to work through the development issues with the installers and ECU manufacturer who it should be said did support me throughout although the last looping issue seemed to come with a less supportive attitude from the installers.

Anyway they did eventually take the car back to tidy up their own wiring and fix a injector wire they had pinched, at this point the installers were ale to see for themselves the car was sill running the Hana injectors they had installed themselves when the wire was pinched. Sadly despite me being clear I would only want to make the journey to collect the car if it was genuinely fixed (I was reassured it was) the looping returned the very next day after I collected my car.

Understandably after years of issues my patience was becoming severely tested, I investigated the problem myself and found if I disconnected the idle valve the looping could be eliminated so that's how I'm running the car to this day as the car simply runs better without it too. I the decided to investigate the issue in more depth as clearly the ECU shouldn't loop with the idle valve fitted as its an integral part of the system, I traced the fault to a wiring mistake made by the installers over 5 years ago which I proved it was not only responsible for the looping but was almost certainly the reason so may ECUs had burnt themselves out over a very painful four/five year period.

This was a very disappointing discovery as the wiring mistake had caused me much inconvenience over may years, however as soon as I'd resolved the installer's error the car ran superbly and I finally felt confident to fit the Yeti injectors, and I'm glad I did because they delivered further considerable drivability and idle quality improvements.

A long answer to a simple question but a story I felt I had to tell, in summary the Yeti injectors are absolutely fantastic and highly recommended.

[spitfire4v8]

I hadn't realised you had now found the true source of the looping prime fault, good work! What was it in the end ?

[Adrian@]

More thoughts on Roush...the company here in the UK that WAS Roush, Revolve.. you may see them as Mountune, are one of the world leading Hydrogen innovators, and had meetings back in the day (pre Cosworth reveal) with LE and GM about supplying engines to the then new TVR project, not then for a Hydrogen engine, BUT, with all the delays to the TVR project to date, had an Hydrogen engine TVR been proffered, we would of still been asking the government for the infrastructure to run such a vehicle! rather than knowing full well that the tech in the new TVR is past it's sell by date. A@

[ChimpOnGas]

spitfire4v8 said:

I hadn't realised you had now found the true source of the looping prime fault, good work! What was it in the end ?

Badly executed wiring relating to the illuminated LPG switch Jules, the looping priming pulse could be eliminated by disconnection the idle air control valve but this was just the consequence of a deeper earth loop issue.

In the simplest terms the LPG switch functions just as a map change switch functions on any other ECU that has switchable maps, I believe you offer this option to your Emerald clients. Press the switch in and it earths pin 2A at the ECU and it switches to LPG mode activating the LPG safety solenoids and switching to the LPG fuel and spark tables ect, press it again and the ECU switches back to petrol mode.

The issue related to the way the switch was wired but more specifically the illumination element of the switch, the blue led ring of light on the switch that showed the car was in LPG mode had been grounded using the same grounding circuit for pin 2A on the ECU, essentially this was causing an earth loop.

I disconnected the illuminated element of the LPG switch and reconnected the idle valve, the looping was gone, reconnect the light in the LPG switch and it returned. Now, I supplied the illuminated switch to installers but the way they chose to ground the illumination element using the same ground circuit as used for ECU pin 2A was certainly not how I would have done it.

I've now fitted a nice new good quality latching button switch without illumination, I can still easily tell if I'm in LPG or petrol because the switch is flush on LPG and protrudes when in petrol mode. I traced the looping issue using logic and some lateral thinking where others had failed and the problem is now completely fixed. Interestingly the looping only came with my latest replacement ECU and the illuminated switch had been fitted from the beginning, but it should be said earlier incarnations of this ECU had suffered many LPG injector driver failures which left me stranded a number of times because when the drivers failed they also fried the petrol drivers too.

I have well supported suspicions all the earlier ECU failures also related to the illuminated switch grounding mistake as while it was clearly creating an earth loop (a potential difference between two grounds) I believe it may very well have been back feeding the ECU and so damaging the delicate drivers. I'm pleased I've found the issue but deeply disappointed it was there in the first place and I myself had to trace it where others had failed, I guess if you wire something incorrectly in the first place you're unlikely to view it as the issue.

I have been significantly inconvenienced by all this, the support had been good up to a point, however the process was very long winded and painful as many emails remained ignored by the ECU manufacturer, I am a super patient and reasonable man but what really started to get up my nose was the installers started to make subtle suggestion I had brought these issues on myself.

The first attempt to shift blame came in the form of a question from the installers ie "What injectors are you running", now I know exactly where they were going with this, basically the suggestion was I had suffered my last ECU failure because they'd seen my post about the new Yeti injectors I'd purchased and assumed I'd fitted them. The thing is I hadn't fitted them but I did discover the acussing installers had themselves pinched an injector wire when they fitted the Hanas which again was disappointing, the bare wire they left could have easily have been causing running issues from a fully open injector or indeed one of the many ECU failures?

Secondly when the replacement ECU came with the looping fault it was suggested I had fitted a small Davies Craig electric booster water pump and this was why the ECU was looping, fortunately I keep all my emails and went back through my records to prove it was actually the ECU installers who fitted it themselves, no apology was forthcoming.

Finally I was told my wiring needed tidying up and this was going to cost me over £300, understandably I baulked at this as it was the installers own wiring, indeed I had even paid them to tidy it up on another occasion which never sat well with me but at the time I just sucked it up.

After all this they did take the car back but it was only after an email war and one I was able to win because I kept disproving their accusations it was my fault with email evidence. Taking the car back was fine and the wiring did indeed look a little neater when I inspected it, sadly the looping issue it went in for returned almost immediately after collection so clearly whatever they did in the three weeks they had my car was not successful.

Obviously after all this my patience had run dry and I now needed to make a decision on how to progress, essentially it was a decision made for me by the actions and attitude of others so I've had to cut the ties and move on as my supply of chances has run out. I've learnt in life if others can't help or solve a problem after being given many chances I need to move on to fixing my own problems, so that's exactly what I did. I am a qualified mechanic and I did spend some years involved in restoration but that was many years ago I am certainly no electronics engineer or engine management expert and neither should I need to be, this is why I recruited the help of the specialists so I was doubly disappointed I needed to resolve problems myself.

But solve them I did, so that's the end of that, many lessons learned and while the experience did leave a bitter taste in my mouth, in a way it's reassuring to know how things work as this allows you to fix them yourself. However I can not build myself a new ECU and with the extensive record of failures stretching back many years I only think it's fair and reasonable I should be allowed to keep the spare ECU kindly supplied to me by the manufacturer, at least this way if I suffer another failure I can plug it in to get myself home.

[spitfire4v8]

You've done well to spot that issue ! I guess the installer didn't see it because it's a bit like the error on the hubble telescope .. they used the same equipment to test the lens/mirror shape as they used to create the shape in the first place. Sometimes you need a fresh set of eyes to see clearly what's what.

You're right about the earth issues .. I use up to 4 separated earths for my ecu installs .. it takes next to no extra time to separate them out as opposed to linking earths together. The only things I would consider linking would be relay earths if the relays had flyback diodes in, but even then I would prefer to ground them separately.

Hopefully you now have many years of good service from the install