prins vsi oddness .

[robertXX]

hello chaps ,


on medusa , my front engine reducer, a early vsi , is being fed lpg , but its not coming out of the other side at the 17 psi i require, in fact, its not coming out at all .

is there anything inside one of these reducers, like a blown diaphragm or o ring ,that would create a safety measure that can block outward flow of gas ?


thanks ,

regards
robert

[LPGC]

It is usually the solenoids that get stuck closed by heavy ends, particularly on VSI reducers. But they also seem to be more prone to getting gummed up with the same inside than most other reducers.

[robertXX]

thanks simon , that sent me in the right direction , not sure i understand what has happened though .

i primed the system ,and undid the connection to the reducer a few turns ,result , no gas emission . i had earlier tested the solenoid gas valve , and it was clicking .

so , clicking solenoid , but no gas flow .

i took solenoid off and took it apart , the pintle was a bit crusty ..

IMG_4457.jpeg (795.42 KiB) Viewed 640 times

the seat looked fine ..

IMG_4456.jpeg (620.99 KiB) Viewed 640 times

so i gently sanded the pintle smooth , reassembled ,and wopped 12v over its terminals , and it clicked and i could blow through it .



put it back on the car ,and stuff me , it ran on the front engine !!



it was at this point i realised my batch fire magic jet injectors , were only working on 4 of the 6 , the front two were not opening .


pox .

tomorrow ill check the two throttle bodies have not closed , and listen with a pipe to the injectors to see if they are def not working .


regards
robert

[LPGC]

I'm surprised that solenoid wasn't working, they're usually fairly gunged up if it's bad enough not to work.

[LPGC]

I was typing on my phone last post so kept it brief.

There's no real difference in design that could cause solenoids on VSI reducers to get caked up with crud more than other types so I think the difference is probably that the solenoids get hotter on VSI's due to the position they're fitted on VSI reducers, which may be hotter than average. Also if there's a slight leak downstream towards the injectors it would make the solenoid dry out when all the liquid gas evaporated making for more deposits.

Injectors also get a build up of heacy ends, any heavy ends / oil in LPG is dissolved in liquid LPG which acts like a solvent but separates from liquid LPG during the change phase to vapour inside the reducer, the heavy ends can then only build up inside the reducer or be pushed with the vapour to injectors, they will go through filters to reach injectors.

Carb cleaner usually works well on solenoids, don't use carb or brake cleaner for injectors though, for injectors there's stuff like IC12 but it's expensive for a small bottle, there used to be products like LPG injector / reducer cleaner made by Liqui-Moly that worked great and you got a decent quantity but Liqui Moly don't make them anymore.

I sometimes use petrol to clean injectors but depending on make/model of injectors because even petrol can damage some types, not sure about the MJ's. For cleaning injectors that cannot be disassembled like Baracudas I pour some petrol into the gas feed pipe (often using an extended gas feed pipe so petrol pools inside the pipe at the injector end but doesn't backflow towards the pressure sensor or reducer), pressurise the pipe (usually with LPG vapour) and use the gas electronics to pulse them. The Nevo ECU's I often fit feature an injector cleaning mode which pulses each injector in turn for a few milliseconds for around 5 pulses, pauses, moves onto the next injector, repeat, this seams to help shake up the petrol inside the injectors and gives them a bit of soak time between pulses. I disconnect the injector output pipe from the engine to prevent cylinder wall wash etc because even with a very short pulse time the amount of petrol outputted would be a mixture too rich to burn. This causes a misfire on the cylinder with the LPG injector currently being pulsed (the other cylinders are running on petrol between cleaning) but that's not much of a problem because only one injector at a time is pulsed. If the pipe is pressurised and the pressure feed turned off there is only the pressure in the pipe to push the petrol through injectors and if the pipe is setup so injectors are at the low point of a loop in the pipe then you know when all the petrol has been used from the pipe because the pressure drops off a lot quicker when the petrol has gone and the injectors are flowing vapour instead of liquid. Petrol may not be the most effective injector cleaner but it's relatively very inexpensive compared to IC12 so you can make up for less effective with vastly more quantity per cleaning cycle and multiple cleaning cycles. Could think materials inside all LPG injectors would be compatible with petrol because they're designed to be connected to the inlet manifold which will have petrol vapours in it but we know LPG hoses etc are not compatible with petrol, or at least not the ethanol in modern petrol and I'm not sure about all LPG injectors, the Barracudas have fluorinated rubber seals which seem compatible, I haven't tested all injectors with petrol. I have tried some injectors with carb cleaner but that doesn't tend to go too well!

You could run your 2x6 cylinder engine(s) setup on one engine while cleaning the injectors on the other engine? If using petrol you might want to check compatibility with MJ's first or might think not much to lose if some injectors seem stuck closed / broken anyway. When I clean Baracudas etc using petrol the mixture on LPG immediately after cleaning is usually very rich for a minute or so but I think this is at least in part due to some residual petrol in the feed pipe to injectors and the injectors themselves, following this period the injectors tend to respond and flow the same as they did when they were new.

[Gilbertd]

When I had problems caused by my R90E getting clogged up with heavy ends when we had the dirty gas problem, I found that carb and brake cleaner wouldn't touch it. The only thing that worked reliably was thinners which dissolved the gloop. I soaked the diaphragms in it and it didn't seem to affect them so shouldn't affect any of the seals either.

[robertXX]

thanks chaps , i took the magic jet front injector apart today, it all looks spotless ..

IMG_4483.jpeg (93.23 KiB) Viewed 570 times

but it seems irregular when feeding it 12v , so in the end i have decided to fit a set of matrix to the front engine , same as the back engine ... i got these off ebay ages ago , and they seem to be much more reliable on a cold start .


new MJ off ...

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matrix ready to be reloaded ...

IMG_4493.jpeg (172.07 KiB) Viewed 570 times

the nozzles are 3.8mm , not 3mm like the MJ were ..... , so ill just have to see how it works , i can allways remap or drop gas pressure,now at 17 psi , down .


unfortunately i dont' have this matrix plug ...so ill just have to lop it off and solder it all in .



and yes today in the batcave was a 34c dripfest ...


regards
robert .

[LPGC]

Matrix connector to Superseal connector adapter looms are/were available.

[robertXX]

Successful adaptation of the matrix has occurred


https://youtu.be/yd6SZCorS2k?si=EZdbM_2liolsM4NN



much much smoother too .

[LPGC]

Just watched the video and subscribed, my first YouTube subscription.

Looks great! Don't think I've seen much of the cockpit before.