‘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.

[StarBear]

Here's my Virgo Engineer testing this AM:
Tuneup 2 days ago. 49 degrees dwell; 7.5-8.0 BTDC (red mark on right side of V notch); spark plugs light gray coating - wire brushed and gap checked.
Set car out on driveway for 20 min @ 41F, 72% humidity; light wind, light clouds.
Deck lid open.
9:43 AM - cranked; 4-5 rumbles then steady at 1000 rpm (I tend to like my idle set a bit higher, and advance a tad more, than spec).
9:44 - 1100 rpm; steady
9:45 - 1100 rpm; steady
9:46 - 1000 rpm; steady
9:47 - 975 rpm; steady
9:48 - 1050 rpm; steady
A little idle dip at 3-5 min, then back up. (The AAR closing?)
5 mi drive to hardware store; ~ 15-20 min. Warm start @ 900 rpm; steady
7 mi drive home and around the block; ~ 15 min. Shut off. 45F. Full warm start @ 1000 rpm; steady.
Decel valve working fine (though still want to check it and adjust to 20 if needed)
Looks like all fine here in NJ!
(IMG:style_emoticons/default/driving.gif)
Van B: I like where you're going with this.... (IMG:style_emoticons/default/smile.gif)

[Van B]

Here's my Virgo Engineer testing this AM:
Tuneup 2 days ago. 49 degrees dwell; 7.5-8.0 BTDC (red mark on right side of V notch); spark plugs light gray coating - wire brushed and gap checked.
Set car out on driveway for 20 min @ 41F, 72% humidity; light wind, light clouds.
Deck lid open.
9:43 AM - cranked; 4-5 rumbles then steady at 1000 rpm (I tend to like my idle set a bit higher, and advance a tad more, than spec).
9:44 - 1100 rpm; steady
9:45 - 1100 rpm; steady
9:46 - 1000 rpm; steady
9:47 - 975 rpm; steady
9:48 - 1050 rpm; steady
A little idle dip at 3-5 min, then back up. (The AAR closing?)
5 mi drive to hardware store; ~ 15-20 min. Warm start @ 900 rpm; steady
7 mi drive home and around the block; ~ 15 min. Shut off. 45F. Full warm start @ 1000 rpm; steady.
Decel valve working fine (though still want to check it and adjust to 20 if needed)
Looks like all fine here in NJ!
(IMG:style_emoticons/default/driving.gif)
Van B: I like where you're going with this.... (IMG:style_emoticons/default/smile.gif)

SB, what is your idle set at?
That's not much or a high idle but at least things were moving in the proper flow.
Thanks for the vote of confidence too lol!

[StarBear]

SB, what is your idle set at?
That's not much or a high idle but at least things were moving in the proper flow.
Thanks for the vote of confidence too lol!

Van B: After tune up I set idle screw at 1000 rpm. The car has always run best on cool dry weather.