‘74 1.8L L-Jetronic Cold Start Low Idle, Mystery solved! Options

[Van B]

Ok fellas, here’s the run down Aux Air Regulator (AAR) and Cold Start Valve (CSV)/injector both work fine. Many of you have also been keeping up with my high idle issue that we figured out.

But yet, when the car is cold, i.e. room temp, I don’t get the high idle I should on start-up. Instead she cranks a bit and then lumbers to life. Idle lopes around 700-800rpm and then smooths out as it warms.

In all other aspects of operation, the engine seems to be pretty happy.

Thoughts? Experience? (IMG:style_emoticons/default/confused24.gif)

-Van

See post #419 on page 14 for a synopsis of the outcome.

[wonkipop]

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re timing.
thats why i am leaving all this alone until a week at the workshop.
i know what you mean. had to thrash around with the disributor and the timing light over a leaky throttle body gasket last year.

i think i'm running tight on the air leaks front.
we buttoned all that up good a while back and smoke tested carby spray etc.

i decided to get less anecdotal today and watch what it was doing empirically against the clock instead of just what i thought i could recall.

i found minute 2 to 3 interesting and i'll talk to my mechanic tomorrow when i am out at the shop torturing myself on the falcon. i'll bet he has his usual line - "AAV"
to him thats saying the engine warming up is out of phase with the AAV closing down.
but we will test everything all over again including i think sensor ! in the AFM unit.
may as well.

its only the warm up from stone cold that is a little unusual.
the thing runs beautifully once its warm.

i am a bit inspired by your determination to get to the bottom of it and just do it.

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re the CSV after start up.
my view is it does until the thermo switch turns it off.
which might be fairly quick if things are above 50F.
its basically kind of like the AAV.
its thermoswitch is heated by a current.

if i understand it right its going to work from 50 to 68F according to my L jet manual.
the thermo might take say 4 seconds to heat from 50 to 68 and cut off.
2 seconds from 60 to 64 or whatever.

and when its below 50 it takes what it takes to get to 50 and then from there to 68.
with a proviso that no matter what it is max 20 seconds. (thats the factory man test) - otherwise you are flooded.
if it goes for 20 seconds say, its probably arctic conditions like chicago in mid winter.
nothing like that would happen in australia unless you were up at ski resort.

normally its just a quick splash of fuel like a gas pedal pump?
and its not part of warm up beyond that?
given at most it can only last for 20 seconds when its really really cold.
but thats another thing i will go through at xmas with the manual and the thermoswitch.
the only difficult is that xmas in australia is summer and its usually really hot here.