Idle Speed and Air Temp/Humidity Options

[StarBear]

As getting ready for the 2022 Northeast Gathering, I'm encountering a semi-recurring idle issue on my 1974 1.8L LJet FI. When outside air is cool and dry, idles just fine at 950-1000 rpm. When outside air is warm and humid, after warmup the idle falls off to barely running. I've just been adjusting the air flow screw (maybe 1.5-2 full turns) to open it. Of course, the reverse happens - if I preadjust the screw it idles near 1800 then settles down to 1100 after the engine gets totally warm (15 mins or so).
I presume (?) there SHOULD be some regulation, perhaps with the ECU or AFM, to monitor air temp and humidity and make adjustments automatically? I didn't have to manually do this adjustment in the past.
The AAR works and tests out fine. Just annoying to have to pull over after running a while and adjust the screw. (IMG:style_emoticons/default/dry.gif)
Your thoughts @Van @Van_B and @Wonkipop ?

[wonkipop]

its cold down here today.
almost new jersey or maryland in winter - minus the snow.
so i am by the blow heater. (IMG:style_emoticons/default/sad.gif)

i've figured it out.
since we got the real early proto L jet.

the temp sensor is in there.
it modifies the signal the AFM sends out and does it inside the AFM before going out the door.
from there it is just one output sent to the ECU which tells it where the flap is (how much air volume) and modified for air temp (density) in the singular.

the temp sensor is absolutely necessary to L-Jet as its got to know what the density is.

the first buses with L jet (ED engines) got the same thing.
so did the first opel mantas.

neither had pin 27 on the afm plug or used it on the ECU.

then in 75 they did it differently and send two separate signals to the ECU.
one was pure position of flap info.
the other was pure air temp signal info.
the mixing got done in the ECU.

the 7th pin (27) was for that pure temp signal output from sensor I.

they must have decided it was a better way to go in 75.
possibly made testing the AFM easier as you could work out which one was screwing up, the flap and potentiometer or the temp sensor.
whereas in ours they pollute each other before it gets to the pins.
thats why there is that one simple dumb test for the AFM output for ours.
using pins 6 and 9 i think. but the test cannot distinguish it can only tell you that the cocktail signal is right or wrong, but not which bit of the cocktail is the screw up.

there was one other factor with air density and that was atmospheric pressure due to elevation above sea level. for that they could fit an altitude sensor. suspect very few cars got that. maybe if you lived way up in the rockies somewhere? denver ski resorts whatever. that was a gizmo that got screwed in somewhere down near the double relays as far as i could work out.

off to do a cold start test now and maybe drive.
it might not get this cold again and i can just about simulate north america. (IMG:style_emoticons/default/smile.gif)