OK..... well that's interesting......... dont know if this is making me feel any easier!
Pulled off the Stepper-motor mixture adjustment thingy.......
This is it:-
Looks like this disc on the top of the outside is a cylinder, that inside has been milled away leaving a 'gate' about 1/3rd the circumg#ference of teh cylinder, and works as a gate valve to set the 'nominal' flow of gas through the valve.
But I cant fathom how you would turn it.... looks like there's supposed to be a special key or something to move the thing round, and line the arrow on the top up with one of the numbers on that scale.
Its currently set at '4'
Then, INSIDE looks like this:-
Which isn't very clear, but from the other end....
Appears that there is a piston, inside the milled cylinder, and that slides up and down, masking more or less of the gap exposed by the 'gate' giving a fine adjustment controlled by the stepper motor..........
NOW; I have found, I think, the Lambda....
This car does NOT have catalysts, and this sensor is not on the collectors for each bank, like the bosses on Jaqui's exhausts, which dont have anything in them, as she has no cats and no lambdas..... but any way.
First of all; looks like that boss has been grafted into the exhaust; it soesn't look like an OE fit. AND looks like the welding has been repaired, or augmented at some time by exhasut joint expansion paste!
There is a small hole in the exhaust further down-stream (pin hole, nothing major.... but it doesn't SEEM to be leaking around this boss, though I wouldn't stake a beer on it!
So, would a leak around the Lambda or down-stream of the sensor make it read 'funny'?
Next; after removing the stepper thingy; I substituted the mixture valve off Jaqui, as suggested to run it 'open loop'....... Amazingly she ran an AWFUL lot better on gas!
In fact, seems reasonably good! (No she cant stay that way I want that vaklkve back for MY Rangie!)
Gave me a bit of gip switching to gas and cutting out, but once warmer seemed OK and WOULD accelerate; right up to 70. Not exactly brilliant, but a darn site better than before! And I didn't exactly spend much time setting it up.
So it looks like we are on the right lines here.........
Right; back on the drive, with the manual mixture valve still in place, I plugged the stepper back into the loom, and revved the engine to see what it did..... was it siezed as suggested.
Well, that piston in the middle DID go up and down as I revved the engine, so I guess it's NOT siezed.
Which leads me to thing:-
a) As suggested duff signal from Lambda in exhaust
b) Problem with Lambda
c) Problem with Lambda wiring
d) problem with exhaust
e) Problem with LPG ECU not doing the right thing with the Lambda signal
f) The stepper valve isn't doing what it should
g) everything THAT side is fine, but SOME-ONE has bluggered up the settings and I MIGHT be able to fix it by adjusting the twiddly thing you dont seem to be able to twiddle without a special key.......
h) Problem IS with the vapouriser, and fitting my misture screw has just let me mask the fault by choking the volume of gas that can get out of it.......
What do you think folks, and where should I start..........
Intreguingly; when I put Jaqui's mixture valve on, I had to scre it in about two and half turns to get a decent idle, so suggests that this system is delivering a heck of a lot more gas to the mixer.
Also, the piston in the stepper was almost completely choking the hole through the valve when the motor was idling, and only opened fully when I blipped the throttle. Didn't seem too lazy or anything....
SORT of hoping this points to a problem of adjustment, and fiddly fingered people not knowing what they are doing.... but lack of scratch marks on that stepper adjustment suggest that's only ever been twiddled by some-one with a key....... suggesting that some-one was some-one who knew what they were up to!
Would there be a regulator on the vapouriser? Cant see anything obviouse to twiddle down there, but could look.