1.9DG/LPG IDLE ISSUES

[itchyfeet]

Never managed to get my emmegas closed loop to pull away well on closed loop
just disconnected it to tune it with an air fuel gauge open loop
if you leave it rich it has to close right down on idle

[ajsimmo]

Sorry, i meant slightly rich at revs (3-3.5k rpm). On a gas analyser I'd set it to around 0.8 CO on a cold day. Then switch on controller and it should modulate it around the 0.4 mark (roughly stoichiometric). I bet that's leaner than you expected!? Most open loops (and petrol carbs) are set pretty rich, with good reason.

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[ajsimmo]

At idle, you can get it pretty close to perfect. Too rich and it will close right down and cough on pulling away. My Talbot has the emmegas controlling the BLOS evolution, and it works very smoothly without any hesitation.

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[itchyfeet]

Thats what I'm hoping for once I reconnect the emmegas.
I don't understand tuning with no load, how can you know whats happening when your foot is hard down on the motorway?

[ajsimmo]

You look at the lights! I leave the test module attached (in the glove box), and switch to test mode which puts the stepper at default opening (say, for the sake of discussion, half way), and the three LEDs tell you which side you are erring on. Mine's always red at full chat! I can also see the mixture displayed on petrol, and cruising it's flickering quickly back and forth through stoich, so nigh on perfect since I swapped the jet (from a Solex off a DF!)

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[itchyfeet]

Thanks Andrew, removed the lights when I got the gauge, time to put them back I thknk, as said hoping to get it right this time

Sorry to hijack the thread James.

[JamesKT25]

Thanks Andrew, removed the lights when I got the gauge, time to put them back I thknk, as said hoping to get it right this time

Sorry to hijack the thread James.

No bother, I learn from your guy's, I'm a competent mechanic, but get lost with Lpg. The idle screw (smaller) is only half a turn of shut. The power valve is all but closed too. I've opened the power up to about half way. And increased the idle a 1/4. Managed to get a slight idle but again spluttered to a death. I might add the van used to start and idle from cold on Lpg. Previous owner ran it on gas permanently.

Am I best winding out the idle screw in 1/4s until it idles?

[itchyfeet]

Hang on, I'm confused, thread started by saying problem on petrol... lpg runs 'like a dream' now you are saying lpg is not right
Either I re read 3 pages or you give us a summary of the problem again.

[JamesKT25]

Sorry, think I may have missed a step or a post. Problem was originally,

it ran sweet on Lpg but idled fast and wouldn't idle of petrol and was sluggish and hesitant.
I have stripped the Carb and regapped it. Also referred the throttle nozzle and measured the fuel output. Following a video on the wiki.

[JamesKT25]

Put it all back together and it now runs sweet on petrol, even idles fast. So I've turned the idle stop screw down so it idles at a more sensible speed. It revs from idle instantly which it never has done and pulls smoothly.

However, it now won't idle on Lpg, it just splutter and dies unless I can rev it up and hold it off idle with the throttle.

[itchyfeet]

OK wind out ( anticlockwise) idle bypass screw on vapouriser ( small one say three flats - half turn) and try it

[JamesKT25]

Sorry, for the confusion.

I'll try that this eve and report back

[JamesKT25]

Something isn't working right here turned the idle up half a turn. Got the van warm on petrol switch it ove to Lpg. . It's hard to keep it running, blipping the throttle helps until it seems to choke and then die. If I don't blip the throttle it dies. Turn it another half no change. Won't start on gas. Power valve it around half way. I haven't touched the larger screw.

[itchyfeet]

Count how many turns the power valve is open
count how many flats the bypass is open

[JamesKT25]

Power Valve was open 2.
Bypass was open 1/2

Increase, bypass to 1and power to 3 and no change