Does anyone now how to tune the VIALLE gas system?
I have a AU1 Fairmont wagon with the factory Tickford LPG/Petrol system ,i've had the car 3 months the gas convertor started leaking water so ihave replaced it with a used one from the wreckers which fixed the water problem but the motor stalls at idle and when slowing down.
there appears to be no adjustment screws!
ANY HELP would be appreciated.

have you resently disconnected the barrery???

No i have'nt disconnected the battery since i've had the car.

Clean the idle jet out that sits on top of the converter and has a on/off solenoid attached.Some pulling apart will be required.

Thank's eagleaus is that the solenoid with the gas outlet pipe connected to the manifold?

No, there is a magnetic solenoid on top and to the back.It sits over a post so to speak with a large C clip on top..You may need prof help if you have not done it before.

The idle solenoid is the one toward to firewall on the top of the coverter. The middle one laying on its side is the primer.

Undo the 8mm bolt on top of the idle jet plunger, undo the plunger (17mm) and pull it out. Just check that the plunger can move up & down freely inside, give it a good clean with carby cleaner. (not the plastic solenoid leave it alone)

There will be a small round "idle seat" sitting loosely under the plunger.
Pull it out with small pliers, be gentle. Give it a clean with carby cleaner.
Underneath that you will find a small spring, pull that out as well.
Then you will find the idle jet.
Use an old spark plug upside down and screw it onto the top of the idle jet. (its a 4mm thread)
Pull up and the idle jet should come out fairly easily. Unscrew the spark plug off it and hold it up the light and see if you can see through it.
If its black & filthy this is probably your problem. Eventually the plug right up with crap and then it won't run at all.
Give it a good clean with carby cleaner so it looks like brand new.
You should do this every 15,000km. With the taxi's at work we do this once a month/every oil change.
Put it all back together.
Check the resistance on the plastic solenoid. Should be about 12.6ohms +-4%
If its cracked get a new one. They usually still work but its not worth the risk.

Its also important to check the plastic pipe between the converter and the airbox. Disconnect the hose at the base of the airbox and blow into it with your mouth & check that it holds pressure. Any leaks will cause stalling.

I replaced a converter a couple of weeks ago that was leaking coolant internally and it also stuffed the stepper motor. Not sure if it was just a coincidence or did the coolant damaged the stepper.

The best way to check if the stepper is working properly is to remove the stepper motor assy from the converter by undoing the small allen key bolts. Remove the 3/4" hose from the base. Lay the stepper motor assy on the water tank.
Wind down the drivers window and crank the engine over while watching the stepper motor operation. During cranking it will go to full closed and then return to the 1/2 way position. This is the ecu checking for correct operation of the stepper. If this all looks ok, your stepper motor is fine.
Just put it all back in.
Stand well back from the converter while your doing this, it will spray gas out of the top of the converter so don't do this with a cigger hanging out of ya mouth. You only need to crank it for a couple of seconds.
The Vialle gas systems on ford operates entirely independent of the ecu. I mean the only thing the ecu does is operates the stepper motor, and its only job is to trim the mixtures, it doesn't actually adjust the mixtures this is all done internally inside the converter.
You can leave the stepper motor unplugged and the car will still run & drive but it will be heavy on gas & lacking power.

I always use a multimeter to see what the mixtures are doing, this will tell you if the converter is operating ok.
Set your multimeter to a lower V range, neg to the battery and positive to the grey wire in the back of the 4 pin connector going to the o2 sensor.
At idle when you first start the car, these things running pretty rich - usually around the 700mV-900mV range. It wont be that rich straight away though, the reading should get higher & higher. After a couple of minutes when the o2 sensor gets up to temperate the stepper motor will go into closed loop and it will start trimming the mixtures making them go rich then lean etc.
The multimeter should vary between 200mV & 900mV toggling back & forth. If its doing this is everything is AOK!
When the converters go inside they usually do idle any richer than 300mV , if it doesnt get any richer you'll need to put a kit through the converter or replace it.
I'll give you another hot tip, check the voltage drop with the engine running between the battery neg terminal and the engine block. Aim for less than 30mV they are usually all much higher than this. If its higher check your earth strap, clean the mounting points under the bolts back to bare metal. you might need to probe around checking the ohm across the leads to determine where the resistance is. It makes a difference to do this, it gives a more accurate o2 sensor signal back to the ecu which should result in better economy/power & better ignition.

any other questions just ask. glad to help.

Thanks lake111 you obviously now your way around these gas systems!

The pipe between the convertor and air box on my motor is an aluminium flexible tube about 20-25mm dia would there be another tbe inside?

Should it be replaced?

It is cable tied to the top of the fan shroud and i did move it out of the way when i replaced one of the cooling fans