LPG Chimaera (Follow My Conversion)

[Sardonicus]

Yes well done Dave what a relief that must of been should of been found sooner however and not by yourself

[Penelope Stopit]

spitfire4v8 said:

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

Am I missing something here? I am well confused as to why 4 seperate good earth points could possibly be better than one good earth point

Thank you in advance

[ChimpOnGas]

Thanks Jules,

I very much value and respect your knowledge and the contributions you make on this forum to benefit tge TVR community, you always seem to offer good sound advice with no hidden self advantaging commercial agenda.

I've laid my troubles bare which is a risky strategy but I felt it was the right thing to do, it would be easy to take pleasure in someone else's misfortune when they are facing challenges with a competing system, but this is clearly not your way.... which I applaud

The truth is the Canems dual fuel system is an excellent product that delivers outstanding drivability and game changing fuel economy on LPG, the software is super easy to learn and initiative to work with.

But no ECU will tolerate a horrible earth loop like the one I traced, being a direct connection to the ECU is was the nastiest earth loop of all earth loops too. As we all know the importance of getting the wiring element right when switching to an a after market ECU can not be understated, in this case it was just one tiny error but tiny in engine management can become a huge issue that in this case had safety implications.

Anyway thats enough waffle from me, thanks for your moral support on this one Jules it means a lot to me mate

Edited by ChimpOnGas on Wednesday 10th April 20:01

[ChimpOnGas]

Sardonicus said:

Yes well done Dave what a relief that must of been should of been found sooner however and not by yourself

Exactly mate, as with my message to Jules thanks also for your kind comments Simon

Edited by ChimpOnGas on Wednesday 10th April 19:36

[Penelope Stopit]

ChimpOnGas said:

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.

Mmmm, your troubles may not yet be over
If the earth point for ECU Pin 2A is good, the good earthing of an illumination bulb at that same earth point will not cause the problem you were experiencing

Have you considered that perhaps interference from other circuits was causing the problem?

[ChimpOnGas]

Penelope Stopit said:

Mmmm, your troubles may not yet be over
If the earth point for ECU Pin 2A is good, the good earthing of an illumination bulb at that same earth point will not cause the problem you were experiencing

Have you considered that perhaps interference from other circuits was causing the problem?

No because the fault was proven as is my fix, I clearly explain my sence checking testing proceedure above.

For the record the illumination element of the switch was a diode (an LED) not a bulb.

The issue was an earth loop which is a potential difference between two gounds (earths).

In this case we have a switch that eaths the ECU pin, and that same earth was used to ground the light in the swith.

[Penelope Stopit]

ChimpOnGas said:

No because the fault was proven as is my fix, I clearly explain my sence checking testing proceedure above.

For the record the illumination element of the switch was a diode (an LED) not a bulb.

The issue was an earth loop which is a potential difference between two gounds (earths).

In this case we have a switch that eaths the ECU pin, and that same earth was used to ground the light in the swith.

I've got it now

This isn't an earth loop problem, it's a volt drop problem, "well that's what I'm classing it as and as you know I'm nearly always right"

The illumination light was causing a volt-drop on the ECU 2A switched negative and the ECU doesn't like it

I would bet my house that if your diagnosis is correct, the fault could have been cured by uprating the negative to the switch

I think that was a fking really good find, nicely done you clever

[ChimpOnGas]

Volt drop or earth loop the begger kept tripping the ECU over and over.

The priming pulse looped continually so the very real concern was if I was involved in an accident and couldnt swith the ignition off, it could easilly have ended in a human barbeque.

The good news is its fixed now, the car is safe and the has never run better. It was a devilish thing to trace but I was taught to be systematic and methodical with electrics, training which stood me in good stead.

[Penelope Stopit]

I never use the term "Earth Loop" as all it does is make something very simple look very complicated to those that have never heard of it, I enjoy sharing my knowledge and explaining things while keeping to as simple as possible, also in the automotive industry an acronym could be EL which could be confused as meaning Extra Large, then again Volt-Drop.....VD could be confused with a very unpleasant sexually transmitted disease
If you put the two together engineers could end up thinking other engineers had caught an Extra Large Venereal Disease rather than they had discovered a very small volt-drop on a circuits return path

Nicely found and fixed by you, yes a logical thought process is the way forward

ChimpOnGas said:

The good news is its fixed now, the car is safe and the has never run better. It was a devilish thing to trace but I was taught to be systematic and methodical with electrics, training which stood me in good stead.

I can tell by how you post about electrical issues that I didn't train you

Edited by Penelope Stopit on Thursday 11th April 13:45

[ChimpOnGas]

Seven years on and LPG just keeps getting cheaper



This was yesterday in Brum, £0.44p per litre is just £2.00 a gallon, and basically the same as my Chimaera doing 60mpg on petrol

[Classic Chim]

Ffs I sold my LPG car 12 years ago thinking the prices were rising. That’s cheaper than some places back then.
You know it makes sense.

[Classic Chim]

Can anyone offer the science to this question.
If every car ran on lpg would it be better for the environment.

Runs and hides,,,,

[ChimpOnGas]

Classic Chim said:

Can anyone offer the science to this question.
If every car ran on lpg would it be better for the environment.

Runs and hides,,,,

Well yes is the answer!

Trouble is LPG only exists as a byproduct of refining crude oil into petrol and diesel, get rid of all the petrol & diesel cars and the LPG disappears too. However, we aren't getting rid of petrol or diesel internal combustion engined vehicles any time soon, they are here for years to come, this means LPG has to continue too because its an unavoidable fraction that comes weather you like it or not when refining crude oil.

This is why I laughed so hard when people told me LPG was over before I'd even converted my TVR to dual fuel, the truth is LPG is here to stay, and not just for cars either, drive through any rural community and you'll see most houses have a propane tank in their back garden for cooking and heating.

TBH you can't go wrong with a low carbon fuel at £2.00 a gallon when you run a V8, the conversion completely paid for itself in fuel savings a good while back and now at these prices it's a clear saving of over £40 a fill, this equates to some £800 a year or looking at it another way makes my TVR cheaper to fuel than a Fiat 500

[ChimpOnGas]

This thing rocks



The secret is high volume low pressure, running two output hoses on the above 450hp rated Magic Power 3 vaporizer takes care of the flow, this amazing and deceptively diminutive unit serves up a massive volume of gas whenever you ask for it, and it's super small fast responding diaphragm delivers outstanding transients.

But at just 1.1 Bar (16psi) you do need the injectors sized appropriately to keep up , here's my LPG injector nozzle evolution over the last two years of ongoing development and since switching to the far superior LPG Tech Yet Injectors.....



Now pull out some injector duration under acceleration using gas pressure correction to balance any pressure creep, although I have to say the Magic 3 is an outstanding regulator delivering super stable pressures even under big swings in MaP.



Finally optimize those snap acceleration events with transient enrichment....



Tip in is now off the scale good, way better than petrol, it's throttle response heaven folks

Gas is good, this 110 Ron performance fuel is available in a fuel station near you.... and for as little as £0.53p a litre