How to adjust fast choke with auto tranny?

[Poodlehead]

This started out with me driving my car for a while and everytime it sat for 20-30 minutes in 80F weather, it would go into fast idle when I started it (~1200 rpm). I'd sit and wait for it to come off of fast idle by blippin the accel to avoid slamming the auto into GO. It finally does drop to about 800 rpm, but it takes forever.

I thought I could fix this by 'tweaking' the choke so I drilled out 2 of the 3 rivets (ground the head off the bottom rivet) and adjusted the choke. It's held in by 2 upper screws. This worked fairly well but seemed a little cold nature which makes sense, since I had the t-stat out too flushing the system. Now a new t-stat is back in and I'm still having problems.

When the car was warmed up, I adjusted the base idle so it would barely idle without dying. Then I adjusted the screw on the throttle control diaphragm for an 800 rpm idle. Life was good!!!

Get in the car this morning pump gas 2 times and it starts up. After a 3-5 seconds it tries to die on me and I think this is due to the choke being too far open. Anyway I kept it running by pumping the gas. I guess the choke needs to be richened up some, but after I got to normal operating temp, it still wanted to die at an idle and did once. Same thing happened when I left work this evening, ran crappy the whole way home. When I got home it sat for maybe 10 minutes and I go out to adjust the base idle screw. The damn thing started and idled just fine like I made the adjustment to begin with so now I'm really scratching my head.

Is the only way to adjust the choke by rotating it in the housing? I guess there is a critical sweet spot that has to be met without much room for too lean or too rich?

Does the idling real low when it's cold sounds like I have a vacuumn leak causing this or is there some part on the car that's failure is like this? I've got the air cleaner off now with 2 lines plugged and going to drive it tomorrow like that to see what happens.

I appreciate any guidance/suggestions because this is getting old... :mad:

Thanks!

[DanG86LX]

With engine temp < 80*F, choke flap should close completely (after a throttle blip). After like 5min of high -> low idle, choke flap should be vertical and that's choke heater job.
Other than that, the choke opener (CO) is doing its number.
On really cold morning, CO does not open at all for like ~ 5sec. Check vacuum on #26 like 0..5 sec after startup, shouldn't be any!
..but i wouldn't think u could have cold start prob in TX.

[Poodlehead]

It seemed to work better today. I didn't have it die on me at all. Not sure why the change but I'm happy.

Concerning the choke opening, it is working good, but I'd like to tweak it if possible because it always dies after running for 3-5 seconds. My guess is the butterfly opens too far at the beginning and leans out and then dies. Does that make sense and I just need to rotate the cover a little more richer? I'll check vacuumn on #26...

My starting procedure is to pump the gas pedal twice and hit the key. It starts right up and goes close to 2K for about 3 seconds and then dies. I pump the gas 2 more times and it starts right up again and idles at 2K until I blip the pedal.

I let it warm up enough until it goes down to the last leg of the fast idle cam and then I jam it in gear at about 1200 rpm. Does that sound about right? It sure runs sluggish until it's fully warmed up.

Man it's gotten real cold in Texas now, down in the 40s tonight...:D

Thanks!

[DanG86LX]

If u wana make some adj. to choke flap opening follow procedure from Paul's manual pages 11-33..34
Ya.. i had this start-3sec-die for years, sometimes for 3..4 times when outside temp < -20*F which pissed me off, till i found this #26 to choke opener prob. This #26 line is controlled by "Cranking Leak Solenoid Valve" (CLSV) in the emission black box and ECU.
CLSV is a air bleed for #26 (remember vacuum source comes from Choke Opener), which opens only when ignition switch is on III-Start position.
But when is cold outside, there is this thermosensor (or thermo-switch on some models) on the black air box housing which tells ECU to delay #26 air bleeding for like 5 sec, therefore delays Choke flap opening.

Otherwise, the cold start as u described it is normal, same as on my car. ;)

[POS carb]

OMG freaking vacuum lines.

well I hope I don't piss you off but all you had to do was tweak 1 screw. I didn't discover it untli probably the 2nd time I took out my carb, it's a tiny phillips-style screw and it is on the throttle bracket itself. If the carb is still on the car it is on the part closest to the firewall. Look back there, there should be the screw on the bracket right where the throttle cable hooks up. Loosen this to lower your fast idle, tighten to raise. This has no adverse effects on anything else except if you take the screw out all the way it can come out and then the bracket will start to separate itself

[Poodlehead]

Originally posted by DanG86LX
Otherwise, the cold start as u described it is normal, same as on my car. ;)

So are you living with this on your car or did you adjust the choke flapper or ?

Maybe the best I can hope for is once the fast idle comes off the first step and idles around 1200 RPM, that's low enough to put in gear without putting extra wear and tear on the auto tranny?

Guess I need to find the sweet spot for how low I can adjust the fast idle as POS Carb described? That was the screw I adjusted after putting the accel pump in which started my inconsistant idle. Maybe it was just a coincident. Right now it's back to idling consistantly so maybe it had something to do with the grease I used to hold the accel pump, -o-rings and spring in place when assembling it on the car.

When I start it now, it idles a little above 2000 for about 3 seconds and then dies. Restart and it idles about 1600 rpm at the beginning and slowly rises to a little above 2000 rpm when I 'blip' the gas (gave up on the unloader for now) and when it drops to about 1200 rpm, I put it in gear and go. Is that about what you do?

BTW - I made a BIG driveability improvement yesterday by taking the slack out of the tranny cable so it didn't shift so quick. That helped a whole bunch. :D

Thanks!

[Poodlehead]

Originally posted by POS carb
...

well I hope I don't piss you off but all you had to do was tweak 1 screw.

Not pissed off because I did know about that screw. It is a hard screw to find though, but mine had yellow paint on it that helped.

Do you have an auto? If so, I'd be curious as to what your car idles at to warm up (both steps of cam) and how long and how low are the rpms before you 'jam in gear and go'...

Wonder if a poll has been done on this for autos??? :flash:

Thanks!

[POS carb]

well while I still had the Keihin I had lowered the fast idle to about 1200RPMs and then would drive off after about 30 secs. There was hesitation getting on the gas for about the first minute of driving.

Another easier fix you can try (I made this up and it never had any adverse effects on the car)
You can hook up constant vacuum source to the fast idle unloader diaphragm. Basically you tap the pedal before starting and the car will start with its fast idle. The first time you tap the accelerator after the motor is running you will revert to normal idle speed.

[POS carb]

oh yea a little added bit, your choke will also open up 100% immediately after starting if you do it this way. You may have to richen your idle mix a bit. Not reccommended for freezing climates. The screw method is best b/c it doesn't affect anything else, I can't understand why it would cause your car to die so quick. Your car is probably set up very lean.

[Poodlehead]

Heck, maybe after what POS carb said, I'm doing OK or I'll turn the fast idle down a bit and go with it. Don't really want to go with no choke because the ole lady has to drive it too and you know the rest of that story... :) Thanks!

[accordlxi2.0]

hey i did that ,added constant vac to the unloader and when i did that in the morning's it would kinda sputter . but try to remain
at it's idle ,maybe if i richen it it would stop that?

[POS carb]

the diaphragm might be leaking vacuum. Put a hose to it and suck out the air, it should hold the vacuum (tight seal). also you should invest in a vacuum gauge, they are easy to find and with them you can tell a lot about how the motor is running like sticking valves, plugged exhaust, manifold leaks, even fuel pressure