Any LPG guru's on here? Got 101 questions.

[Grega]

joel
the stepper motor to the inlet is for closed loop operation.
its basically an IAC valve from a commodore which opens/shuts to try and give some form of closed loop in the simple gas setup.
there will be a computer somehwere to control this little doovey. that can be adjusted to suit to ensure its doing its thing correctly. sometimes theres no plug they take the lid off on some and there is a potentiometer in there to adjust.
with teh sort of system you have you really can't tune for midrange. they normally set the base tune for idle based on CO2 and PPM output then, bring it up to around 3000rpm (freeway RPM) and do same (then try to find the happy medium)
IIRC the idle speed is on the mixer, the rich/lean is done by the convertor (again depends on your convertor)
personally i'd be off to an LPG specialist to check your setup over.
they're difficult things to diagnose and one small move can end up with a big mess mate, i've been around these systems for years to know.

[TurboRA28]

Hey all, i've recently purchased a 80 series landcruiser on LPG.
I'm very new to LPG and got a bucket load of questions..

Any guru's on here I can fire some questions off to?

Thanks
Joel

[blacktop]

Your fist mistake was buying a car on LPG!

Might help if you post up some Q?'s

[jeffro ra28]

post up your Q's!

Got nothing usefull to say but i got LPG on my PV and its tops. havent had a drama in 100 000 km's.

A usefull link to start off some info
http://www.acl.com.au/web/acl00056.n...e?OpenDocument

[amichie]

I have LPG on my mx83.

What brand and type of system do you have?

Impco is the most common.

[jimmmayyy]

Nothing wrong with LPG, it is in fact a much better fuel than petrol. What do you want to know?

[TurboRA28]

Well here are the basics I know of the system..

The converter has AIROD stamped on it. It has 1 adjustment screw on the top of it.

It has a stepper motor in the low pressure line to the inlet/mixer. Also the stepper motor appears to have an adjustment screw of some sort on it.

The mixer appears to be a plate bolted to the front of the AFM.

I really want to get my head around how to tune it. I've got a wideband 02 meter to assist.

But what does what.. If I have read correctly the screw on the converter is most likely the idle adjustment. What kind of mixtures do I want at idle?

Also how do I tune midrange, top end? Can you tune the stepper motor in anyway, or is this strickly reading the narrow band 02 sensor and adjusting itself to keep mixtures around stoich? Is the stepper motor a means to tune? Or just a component in the system that trims the mixtures? If the later, how do you tune top end and midrange?

I've seen a mates system which has a aeb lpg computer which seems you can read the narrow band 02 sensor from and also the position of the stepper motor. But still no idea if you can change anything here or if you are just reading data.

I can't find anything like this in mine.. I've got the converter, mixer, stepper motor which plugs into a black box with no identification on it, some relays, etc. The box the stepper plugs into doesn't seem to have any additional plug for data/tuning.

It's got a few problems also.. Every so often for no reason at all it looses all power, cant get the revs up, hardly drives, idle is low. This problem comes and goes.. Maybe once a week for a few mins. When it happens I switch to petrol for awhile and when I flick back to LPG its fixed.

Decel feels like shit, at very distinct RPM points you can feel it change. So say 2400rpm and above the car doesn't decel well, it is trying to speed up more so. Under 2400 is a harsh decel then somewhere lower in the rev range it changes again. So no smooth decel which makes 4wding hard.

Sometimes when on LPG the revs wont drop, get stuck at aorund 2000rpm. Have to slow the car down to get them to come down. On petrol this doesn't happen so I don't believe its an air leak.

Probably have more.. But thats a start
Sounds all bad, but when driving around on cruise it's awesome. Just need to get my head around the system and how it works so I can tune it and also to nut out these few problems. But with no understanding of how it all hangs together I can't really start troubleshooting.

Cheers
Joel