Thanks Mcgyver, just rebuilt my OMVL and tuned to your specs- perfect. Cost me $8 tin of carby cleaner. Not bad for 886,000 AU3 ex taxi...

Can someone explain this part of the instructions in a clearer term for me (ISC means nothing to me, and do i asume the throttle stops is the idle screw, and is the ECU being mentioned the cars normal Petrol ECU or the LPG ECU.

Sorry, I'm just not 100% up to the terms for injection cars with all its wiz bang sensers and these newer lpg systems with managment controls.

ISC stands for idle speed control i think, i'm wondering the same, i have a BA ex-taxi with a landi converter and wasn't sure if the BA's have an ISC?

I had trouble starting on LPG and researched to find the start solinoid was on the bottom and was prob. full of wax from the gas. so i pulled the converter off and pulled apart the solinoid and was really sticky so i cleaned it with throttle body cleaner by threebond and also filled the converter with it, just sqirted it back through the gas feed and heaps of crap came out. i also sprayed in the throttle body and the gas feed ring inside it.

car starts first time and gets 2l per 100k better economy now, but i'd like to do the tune with the screws now too.

It's amazing how simple LPG is to fix.
My car is now running sooooo nice since I got the OMVL converter in and tuned I havent touched it since August. starts first go. idles perfect. no surging or stalling. runs when cold or hot.

alas now i have another problem, my BA will start and run but turns itself off after a minute or so and the check engine light comes on just before it shuts off.
I plugged in an OBII conector but it said nothing.....
im wondering if its a speed sensor or the tank solinoid, how does one dispose of 100l of lpg?

hey can anyone help my gas is different to everything else i think. i have a 94 ed wagon and the gas has the converter up on the suspension on the LH side but in front of the throttle body it has another one not both don't have 2 bolts the converter (1st in line on the suspension) has a 10mm bolt and a spring button thing on the side and the part near the throttle has a 11 i think its only a tiny bit bigger than the 10mm but the problem is i have no lowdown power at all anything under 2500-3000rpm has no guts in any gear. ive put a bigger intake on off a xh i think and that's helped over all but i have a feeling its running a lil lean.

ill try to get photos up asap

That sounds like what i have on my EA, its a vacuum type, im experiencing the same issue, no power down low and backfires if i am under 2000rpm and loaded.

i had backfiring get gas leads and a new cap and rotor that will fix it.

Agreed with above, i replace with good lpg topgun leads, never had a back fire again.

Could some on put some photos and guides up on Complex converter cleaning. im afraid to clean mine with TB cleaner as i know it eats plastic.

any tips and guides etc, arrows point at stuff, all helps. followed the guide to the tuning, best thing i ever learned! thanks guys!

im going to be mucking around with porting mixer ring style mixers soon plus polishing. will see if it helps any. plus chuck some pics up and before and after measurements.

Hi all. I have just fitted a balance pipe to my sprint gas systerm and have now got a surging problem when around 2k to 3.5k rpm. I have tried screwig in and out the 10 mm screw but still no better. Any tips¿ I will try a full tune as per this thread when i get some good weather.

Thanks all

thanks for the doco on this one. made a huge difference to the gas system on my fairmont.
such a simple setup too with the omvl converters.

Thankyou Scott for the very informative post on how to tune your LPG system.

I have read as much info as I can about turning the same OMVL R90E converter however your post seems to be the most reliable I can find. This is my first attempt at tuning an LPG vehicle and the vehicle is modified so I'm unsure if it is the tuning process or the vehicle presenting a problem. What I do know is that the LPG system was working 100% before the turbo installation. I believe everything is installed correctly with a balance line after the turbo but before intercooler connected to the converter.

Basically when i try to tune the system, I can not get it to work without stalling when ever throttling off. It doesn't matter if the intake has positive pressure or not, it will always stall. I have tried adjusting both the sensitivity and idle adjustment screws however no combination seems to make a difference. Is this a tuning problem or most probably something to do with the balance tube? It seems to work fine when accelerating.

Cheers in advance for any help.
Shane




Vehicle
1999 GU TB45 4.5Litre Petrol with aftermarket Turbo.

I GOT THIS OFF A ENGLISH WEB SITE IT IS FOR OMVL 90E AND IT TOKE SOME FINDING TO,,,, LPG Vaporizers and Tuning - The very basics . . . .
« on: January 27, 2006, 14:27:28 PM »
OK - Here is a little guide to the very basics of a vapouriser and basic tuning.

Assumptions:

Your timing and things are set reasonably OK. I'm not going to argue over whats the best timing as every engine is different. 6° to 8° BTC should be enough to get you firing.
You ignition circuit, sparks and leads are all in good order. No spark - No bark.


The Vapouriser

Based on an OMVL R90 vapouriser, and ignoring how it changes the liquid state LPG into gas, the part of the vapouriser that meters the amount of gas to the engine looks similar to this:



The big diaphram gets pulled ( downwards in the piccie ) by the suction from the manifold. This then pulls on the arm. In turn at the other end of the arm, the arm controls a little cap covering the main large outlet of the gas. The more the arm is pulled by the diaphram, the more the cap opens up the hole and the more gas you get.

How much the arm moves in relation to the vacuum is controlled by the spring. The larger of the 2 adjuster screws puts preload onto the spring that the arm has to push against. The more preload, the more vacuum required for a given amount of gas delivery.

The second smaller screw directly controls the opening of a smaller vent hole supply of gas to the engine. This supply is given regardless of the position of the arm / manifold vacuum. So even at idle with the throttle body all but closed over and no displacement on the arm ( and thus no opening of the main supply ), this vent will allow a steady flow of gas to the engine, and thus its called the idle bypass.

The smaller idle bypass adjustment screw is magnitudes more sensitive compared to the tension adjustment screw. Its in the range of 1:6. Supposedly 1 turn of the idle bypass screw will delivery the equivalent of 6 turns of the tension adjuster.

For both adjuster screws:

Turning the screws clockwise towards the the body of the vapouriser will reduce the gas supply. Turning them anti-clockwise will increase the gas supply.




Enough already - Just tell me how to adjust it all . . . .

[ If the engine doesn't run atall on LPG, then goto the bottom section to get some hints / ideas. ]

First of all, get the engine upto normal operating temperature.
Assuming the engine runs on gas, just not very well, then:


Open up the max power adjuster on the gas feed pipe that runs to the manifold. On the large rubber tube, there should be an adjuster valve which can close the diameter of the feed pipe. Turn this so that its fully open and is not restricting the flow of gas.

With the engine idling...
Turn the tension adjuster ( the large one ) outwards a lot to make the diaphram really slack. This will mean that plenty of gas is supplied to the engine when it sucks.
Then slowly turn the idle adjuster clockwise all the way in so it fully closes. If you find the engine is stalling, then unscrew the larger one to reduce the diaphram tension to keep it idling.

[If you cant do this without fully stalling the engine, then stop screwing the idle bypass inwards - leave it at a point where the engine just manages to run ]

Now with the idle bypass closed off, slowly start to the increase the tension on the diaphram by turning the 10mm adjuster clockwise and inwards.
Eventually, you should see the engine start to slow drastically down as the gas supply is cut off.
Stop when the engine is faltering under the normal idle speed, but still managing to run.
Now to get the engine back upto a normal idle, unscrew the smaller 8mm idle bypass adjuster . . . SLOWLY . . . this is a sensitive adjustment so do it a little at a time
On mine, after about 1 1/2 turns, the engine speed will pick up and start to return to a normal idle.
Adjust the idle screw until you reach a smooth idle speed. On mine its idles at about 800 - 900 rpm.

Now what you have set is the idle is controlled by this bypass adjustment, but if there is anymore demand from the engine ( by the throttle body being opened ) then the diaphram will immediately move and start to supply the additional gas.

Next step is to adjust that max-power adjuster that you fully opened at the start ( you did remember to do that didn't you? ) The max power adjuster just clamps and sets a limit to the top amount of gas flow that is given at the higher revs and loads.

To set this, get someone to rev the engine to about 3000rpm and keep it there. With the person holding the pedal steady, screw in the valve until you hear the engine start to slow slightly ( with the person still keeping the pedal still ).
Then unscrew ( open up ) the valve 1 complete turn.
Now you have set a limit that you know the engine will run at high revs with enough gas, but that you won't be letting an excessive amount through.


Then go back and re-do the 2 vapouriser screw adjustments just to be sure that the max-power adjustment hasn't upet the vapouriser setup.

And that should be enough to get you going reasonably well.



Naah - its no working and its peeing me off . . . .


If its simply not running atall, then you need to double check all the other parts. To think of the main ones . . .

Are all the LPG solenoids clicking open OK.
Are the manual shut off valves ( if fitted ) on the LPG tank outlet opened up?
Am i definietly cutting off the petrol fuel supply?
Is the diaphram properly sealed and seated? Normally 6 screws on the back of the vapouriser - are they all tight?
Is the arm connected properly to the diaphram?
Is the diaphram in good condition and not torn.
Is the tension spring putting a good adjustable range of tension on the arm? ( Mine wasn't so i had to adjust the spring's length a little )

Last edited by BIGNICK on Fri Dec 16, 2011 1:47 pm, edited 1 time in total.

I did my car with this and now it runs like new das not stall when you turn corners or put your foot on the brakes to stop at the lights it toke me a lot of finding on the net but at last i have it and hope it will help yous

you need to fit a plumb back BOV. when you close the throttle positive pressure builds up and the gas is not drawn into the manifold, the air basically stalls in the intercooler piping stopping any gas from going any further down the intake.