Idle Stop Solenoid revisited

[18Fiatsandcounting]

The 32 ADFA carb didn't come with a manual choke, so perhaps someone added this later? Again, going by memory here, but the ADFA should have a choke that has engine coolant hoses attached to it, so the choke comes on and progressively "turns off" as the coolant warms up. Later models had an electric choke, but I'm not sure when this happened. Again, going by memory here.

One thing to check: With the top of the air cleaner removed and the engine off, do the choke plates at the very top of the carburetor throats close and open as you pull and push on your choke knob?

As for backfiring, that's often caused by a mixture that is too lean. When you quickly let off the throttle, the air / fuel mixture can go way lean, and since lean mixtures burn more slowly, the mixture is still burning after it exits the engine and enters your tailpipe. That's the backfire. Many possible causes for this, but let's figure out the choke first.

-Bryan

[CharlieB]

Bryan, flap on the top of the carb does not move when I pull the knob. Should it?

[18Fiatsandcounting]

Yes, these flaps should move. In thinking about it some more, perhaps the lever on the left side of the steering wheel really is a throttle lever and not a choke lever. Some models may have moved this throttle lever from the right to the left side, when the choke lever was no longer needed for the carbs that had an automatic choke.

One test: With the engine cold and without having pressed the gas pedal, those flaps at the top of the carb should be initially open. When you depress the gas pedal all the way to the floor (engine off), these flaps should close. If they don't, your automatic choke isn't there or isn't working.

-Bryan

[CharlieB]

Bryan, I just looked at my owners manual and the knob is labeled as "throttle knob", sorry. My carb only has 1 flap on the top, on the primary barrel. I'll take a look after work and see what happens when I press the gas pedal. I know that is supposed to engage the choke but I'll let you know what happens.
Thanks for putting up with me on this.
Charlie

[18Fiatsandcounting]

Not to worry, Charlie, we're getting closer! Yes, pulling that throttle knob would definitively rev the engine. Check your automatic choke, and if you have only 1 choke flap on the primary throat of the carb, that's OK too. Some carbs have 2 choke flaps, some only have 1. Depends on the model.

-Bryan

[dinghyguy]

A 32adf has 2 barrels both with butterfly flaps

And as Bryan said either hot water or electric automatic choke unless it has been modified

How about some pictures of the carb?

Dinghyguy

[CharlieB]

Bryan,
I pressed the gas pedal to the floor and the choke does not move. I had to run some errands at work so the engine was warm, not sure if that matters or not.
Dinghyguy,
Here is a pic of my carb. Hopefully I linked that right.
https://imgur.com/a/egN3yi3
Thanks guys

[18Fiatsandcounting]

Yep, the picture is fine. At the bottom of the picture, there is a round bell-shaped thingie with two 1/4" hose barbs sticking out of it. That's your automatic choke, and when the carb was installed in the car, there should have been two coolant lines attached to this thingie. When the carb (engine) is cold, and you press on the gas pedal all the way, that choke flap on the middle left of the picture should swing closed. As the engine warms up (coolant gets hotter), the choke will slowly open the flap to the full open position such as seen in the picture.

Methinks your automatic choke isn't working. Fairly common occurrence. Could be stuck, something broken internally, not connected right, etc.

-Bryan

[CharlieB]

Bryan, I remember a few years ago I fiddled with that, I forgot that was the choke. The little spring inside broke a few years ago but I replaced it with a spring from another 32 ADFA I have for parts. That spring may be part of the problem. It wasn't in great shape when I put it in. I'll try to track down a new spring and reset the cam and see what happens.
Thanks,
Charlie

[CharlieB]

I tried pressing the gas pedal to the floor when it was cold this morning and the choke did not move.
So I pulled the carb off and cleaned it really well again. I looked at the spring inside the choke and it was in good shape. So I decided not to replace it. I ran through the adjustments from the Weber manual but everything was where it should be.
I put the carb back on and tried the choke again...no movement still. So I don't know what to do about that.
I drove around the neighborhood and the car cut off when I slowed down at stop signs 7 times out of 10. At EVERY slow right hand turn, the car cut off.
When I got home I rotated the choke housing clockwise and counterclockwise and drove around after each change and still running like crap. I also tried adjust the fast idle screw, but that didn't help either.
So basically if I downshift to stop or slow down under 10 mph or so, the car cuts off.
So I don't have a clue what to even try to fix at this point.
I guess the choke needs to be fixed first, but I don't know where to begin.
Charlie

[18Fiatsandcounting]

If the engine is fully warmed up and still stalls when you slow or turn right, it's not a choke problem at that point. So, I think you have two separate issues (choke not working and stalling). Taking each one in turn:

Choke not working
With the engine cold, the choke should be set up so that, when you fully depress the accelerator just once, this releases a ratchet/pawl mechanism that allows the spring inside the choke mechanism to fully close the choke flap. Then, as the engine coolant warms up and thus warms up the choke mechanism, the tension on this spring is slowly reduced so that it progressively swings the choke flap open until, when fully warmed up, the flap is all the way open. That's how it should work, but it doesn't sound like yours is doing that. My guess is that something was installed incorrectly when you reassembled the choke mechanism, or perhaps something is missing.

Stalling
A few possibilities. I think you set the float level to the spec, but if this is set so that the gas level inside the float bowl is too high, when you turn right, gas will shift to the left of the float bowl, which is the "intake" for the primary fuel passages and could "flood" them with gas, possibly causing the engine to run way too rich and stall. Kind of a long shot in my view, but it could happen I guess. The second possibility is that you have a loose connection in your ignition wiring somewhere, and when you turn right, it breaks the connection just enough and the engine stalls. An intermittent short might also do this. To test either of these possibilities, put the car in neutral and let the engine idle. Rock the front of the car by hand fairly vigorously up and down and side to side (don't let the hood slam you in the head...). If the car starts to stall, then you're onto something. Possibility #3: Not to overload you, but there is another system called the fast idle device which uses engine vacuum to operate a valve on the carburetor and raise the idle speed when the transmission is being shifted from one gear to the next. Had something to do with reducing emissions, if I recall. Anyway, if this part has been disconnected from the carb, it's possible you're getting a vacuum leak when shifting, thus stalling the engine. That wouldn't explain why it does it when turning right, but maybe in combination with a float setting that is out of whack?

I'm not sure I'm helping or just making things more confusing, so I'll stop here and let others chime in.

-Bryan

[CharlieB]

Bryan you are most definitely helping and I appreciate your patience and info.
I went out and tried shaking the car to reproduce the problem but it didn't do it. I also tried turning the wheel and shaking some of the wires under the dash, but nothing changed.
Now, this may be totally irrelevant but, I removed the idle stop solenoid and pulled it apart and there is no needle inside it.
Shouldn't there be? Or is this part of the modification to take the idle stop solenoid "out of play"?
Sorry, I know I keep throwing curve balls into the equation but something is bound to be relevant.
Thanks again,
Charlie

[18Fiatsandcounting]

I think everything you're telling us is relevant, so keep it coming. As for the needle valve at the end of the idle stop solenoid, yes, this should be there. Perhaps this was removed since the 12 volt wire to the solenoid was removed, in which case the idle might work without the 12 volts, but it would likely idle way too rich. This might cause some of the symptoms you're seeing, although the "right hand turn stalling" still has me stumped.

I hate to say it, but I think this carburetor needs a thorough going over to see what is missing and/or not working right. We can certainly walk you through that, but the first step would be to Google "Weber 32 ADFA diagram" or the like and compare your carb to this diagram to see what's different. My fear is that, when the emissions control systems were removed/disconnected, a lot of things changed that are causing the car to run like you're experiencing. Sometimes you can just disconnect a particular emission control system, but other times you have to make adjustments somewhere else to compensate.

Where are you located? Any Fiat clubs in your area that might have someone familiar with your carb setup?

-Bryan

[kilrwail]

After following this conversation and rereading it several times, I have to think that there might be an electrical issue behind the problem of stalling when coming to a stop or turning right. If the carburetor was at fault the engine would sputter or fart or backfire when failing, but not likely just stop cold. Have you checked the ignition system? How old are the points and condenser? Have you verified the timing and points gap (dwell angle)? How about the plugs? You should check all electrical connections at the coil and distributor as well. Are you running a single set of points or is the dual point arrangement still there? Make sure the wire from the distributor to the coil is not loose or frayed where it goes through the hole in the distributor base, where it might ground intermittently.

[18Fiatsandcounting]

After following this conversation and rereading it several times, I have to think that there might be an electrical issue behind the problem of stalling when coming to a stop or turning right.

I agree that electrical is still a possibility, and here's one other idea: You have a poor connection at or within the ignition switch so that the power to the ignition circuit cuts out when the steering wheel goes to the right. You can test this by letting the car idle in neutral and then wiggling the wires coming out of the back of the ignition switch. If the engine falters or dies when you do this, then your problem is a bad ignition switch (fairly common actually) or the wires going to the switch are loose (an easy fix to tighten and reconnect).

Also, does the engine stall if you are just sitting in neutral and turn the steering wheel all the way to the right, or does it only stall when you're moving and turning right?

-Bryan