Trying to solve the idle issues

 

Here's the good:

 

The choke sets fine, and opens fine as the car warms up. The electrical connection to the choke seems good, as is its heat line from the RH manifold. The choke pull-off diaphram happily goes about its business, too. I'd cautiously conclude that the functional parts of the choke work okay.

 

Here're the questions:

 

When I shut off the car, the throttle solenoid goes all "scared turtle" and sucks back into the housing about half-way. I'm assuming that's supposed to happen due to a loss of electrical power to the solenoid, correct? 

 

Then, when I re-start it, the solenoid button pops back out and contacts (perhaps just) the tab on the throttle linkage. However, this leaves it in a rather sour idle. ONLY when I lightly tap the throttle (or nudge the linkage by hand) does the throttle linkage move back slightly, off of the solenoid, and the idle stabilizes to a good place (no tachometer, just by ear, and with the car at idle). It almost feels like the throttle linkage is sticking, needing just that extra something to get where it needs to be. Any ideas what is causing this? Am I right that something is sticking, or does my off-idle adjustment screw need adjusting to make that initial start-up condition good?

 

The fast-idle cam arrangement is impossible to see on the damn 2150, so I can't tell if it's adjusted properly. However, I'd hazard to say that whatever's causing the low idle at warm is the same thing that's causing me to stall every time at cold.

 

What is the relationship (physically, and functionally) between the fast idle cam and the throttle linkage? I notice both move when I move the throttle linkage, and that's what made me wonder if the fast idle setup may not be set correctly. Would too low an idle be caused by the fast idle screw too far in, or not far enough?

 

Thanks for any help!

 

No, my stovepipe and heat shield are missing. An odd thing to have lost over the years!

 

That should only affect warm-up, though, not right when the car starts (exhaust isn't even hot yet) or after the car's warmed up (when the thermac would be open anyway), no? 

Clockwise increases speed, Counterclockwise decreases. On a Holley 4bbl you have to go WOT (WITH THE ENGINE NOT RUNNING) to be able to really access the screw. Even then, it's guess work, 1/2 a turn at a time.  From what you've said, I'd probably try increases the fast 1/2 a turn and the cold 1/2 a turn, and note what it does. (this is kinda hard to do w/o a tach, FYI, You can always get a cheap one and wire it temporarily).

 

However, one thing I don't understand is the point of the TSP (solenoid): at anything more than light throttle, the linkage no longer contacts the solenoid button, so I don't know exactly what it does. I've been adjusting the "off" solenoid idle screw (the one that is vertically-oriented, further back under the kick-down rod), but do I need to adjust the big spring-loaded screw in the bracket into which the solenoid is mounted in order to adjust the "on" solenoid warm idle?  Geez, how many idles does a car need LOL? How can the car idle "off" solenoid and "on" solenoid, shouldn't it just have cold idle and warm idel?

My 1977 Ford manual says to check the TSP off speed with the plunger of the TSP collapsed, which I interpret to mean holding the throttle linkage forced against it to make it shrink back into its housing. Then, check the speed by adjusting the "throttle adjusting screw". I'm assuming this means the one I've been playing with to-date, and NOT the one on the bracket that supports the solenoid.

 

But, then it talks about adjusting curb idle speed, and it just says, "adjust to specification", not mentioning which thing to adjust to achieve that specification. Is this when the solenoid bracket screw gets adjusted?

 

I removed the solenoid today, and the car ran (and shut off) fine without it. It didn't seem to need the extra little boot of gas to get it to idle nicely. So, perhaps it is a little "weak in the pooper" and can't quite get to where it needs to be. At that rate, I might just leave it disconnected!