Idle Stop Solenoid revisited

[CharlieB]

I have a '76 Spider with a 32 ADFA carb. The idle stop solenoid is attached to the carb but the wire that attaches to it is not connected to anything. In other words the solenoid has an open end wire attached to it so it is obviously not getting power. It has been like this for at least 4 years. I know the solenoid is supposed to attach to the tachimteric switch, but I don't have a tachimetric switch.
My question is, what's the best way to wire the solenoid to have power? I'm terrible when it comes to electrical issues, so hopefully there is a simple way to do this.
Any help is greatly appreciated.
Thanks
Charlie

[SteinOnkel]

Does the car run? If the idle solenoid isn't energzied, it shouldn't.

[18Fiatsandcounting]

Does the car run? If the idle solenoid isn't energzied, it shouldn't.

Unless the idle stop solenoid is stuck in the "on" position, in which case it doesn't matter whether it's getting power or not.

-Bryan

[CharlieB]

Bryan the car does run. So maybe I should just leave it alone. I do have an odd issue that only happens occasionally. If I slow down and turn right, into a parking lot for example, the car will cut off. It's ONLY when I turn right. I thought it might be a float issue, but I have adjusted it twice and it still happens. Very odd.
Anyway, I guess the solenoid is not to blame.
Thank for the response Bryan

[dinghyguy]

On my 79's with 32 adf the switch is connected to the ignition circuit so it gets power as long as the key is in the ON or start position.

I have heard that some people trim the tip off of the solenoid so it is not needed.

cheers
dinghyguy

[18Fiatsandcounting]

I kinda doubt the right-turn-issue is a float issue, as the float can move up and down when the car moves forward or backward, but side to side movement generally doesn't affect the float level much.

The idle stop solenoid usually has 12 volts applied to it when the ignition is on, thus allowing idling fuel to flow, and when you turn the ignition off, it shuts off the fuel flow to the idle circuit so that the engine doesn't "diesel" when you turn it off.

The idle stop solenoid looks like:
https://autoricambi.us/products/carbure ... oid-197578

I suppose if the idle stop solenoid were goofy, it could cut out when you turn right.

-Bryan

[CharlieB]

Another issue is the car will cut off if I'm coasting to a stop and shift into neutral. Not every time, but often enough to be a headache. Lately, if I back out of my driveway and start to shift from reverse to first gear, the car cuts off.

[18Fiatsandcounting]

Another issue is the car will cut off if I'm coasting to a stop and shift into neutral. Not every time, but often enough to be a headache. Lately, if I back out of my driveway and start to shift from reverse to first gear, the car cuts off.

A couple of questions:
1) So, you're driving along and put in the clutch with the transmission still in whatever gear. The engine speeds drops to idle, but the engine doesn't stall (or does it?). Then, when you shift from whatever gear into neutral, the engine stalls? That sounds to me like an electrical issue.
2) Is your driveway sloped? A lot?

-Bryan

[CharlieB]

Bryan, my driveway is flat. The car will cut off the moment I shift out of reverse...before I get into first gear.
When I'm driving at 15 mph +/- or above everything is fine. It's only when I slow down at a stop sign, or to make a slow turn that the rpms drop quickly and the car cuts off.

[18Fiatsandcounting]

At this point, it sounds like you have a weak / flaky / partially blocked idle jet / intermittent idle (pick one), and the idle stop solenoid could be part of the problem. I'd first make sure that the idle speed is where it should be (850 rpm, noting that the tachometer in the dash isn't always accurate), and the idle mixture screw is set for a smooth idle. One possible fix, although maybe just a band-aid, is to increase your idle speed to 1000 rpm or so.

One way to check the idle is to start the car and warm it up, put the car into first and hold the brake pedal, and SLOWLY engage the clutch partially, but not all the way. If the engine dies as soon as the clutch starts to engage, your idle is weak, meaning that the engine isn't developing much power at idle and it doesn't take much to stall the engine. If the engine slows but doesn't stall as you start to engage the clutch and the car feels like it wants to move forward, your idle is probably fine. On my cars, if I slowly release the clutch in first gear on a level surface with the brakes off, the car will move forward just on the idle, that is, without giving it any gas. Of course, if I abruptly pop the clutch out, the engine will stall. If you do this test, make sure there's nothing in front of the car that you would crash into!

I'd also go ahead and replace the idle stop solenoid, although of course you would have to find a nearby source of 12 volts when the ignition switch is in either the on (run) or start positions. Ideally, you could locate the original wire to the solenoid. There were 2 diameters of idle stop solenoids on these cars over the years, 8 mm and 10 mm. Make sure you get the right size for your carb (I believe yours is the 10 mm size). Also make sure that the idle jet that inserts into the end of the solenoid isn't blocked, as a partially blocked idle jet could cause some of the symptoms you're describing.

-Bryan

[CharlieB]

Thanks Bryan, very helpful info. I'll take a look at it tonight.

[18Fiatsandcounting]

Charlie, there is one other possibility, but it's a stretch. On some model years, there is a switch on the transmission and a switch on the clutch pedal that are connected to the Exhaust Gas Recirculation (EGR) system. If the EGR has been removed/modified/broken, then it's possible that when a gear is engaged, the EGR system does it's thing, but if it's not there or broken, a vacuum leak can occur which will cause the engine to stall at idle. At higher speeds, the vacuum leak isn't as noticeable (but still not right).

I happen to have an owner's manual for a '76 spider, and it does show an EGR. If everything isn't working right, the combination of the right conditions of the clutch and transmission could cause a vacuum leak which would likely stall the engine at idle.

If you can find the control valve for the EGR system, it should have 2 wires coming out of it. Disconnect one (or both) of the wires and see if you still have the same idle problem when you shift.

-Bryan

[CharlieB]

Bryan, that's a very good possibility. The EGR system has been removed and capped / plugged. The port on the carb is capped and it is possible that that cap (along with others) may need to be replaced. I'll replace all of the caps tonight and see if that does anything.
You mentioned that there are 2 wires coming from the valve. Would those be at the transmission? I have had 2 wires dangling on the side of the transmission since I owned the car.
Thanks
CB

[18Fiatsandcounting]

Thanks, Charlie, and I think we have found the "smoking gun". There are usually two switches for the EGR control valve: one on the transmission, which you have located, and one on the clutch pedal. If you look way up under your dash, close to the bolt pivot (hinge) for the clutch and brake pedals, there should be a switch on each of those. The switch on the brake pedal is for your stop lights, and the switch on the clutch pedal (if still there) is for your EGR system. Since your transmission switch is already disconnected, you can just leave the clutch switch as is, since it's not doing anything at this point.

As for the EGR control valve, it was possibly removed when the rest of the system was removed, or maybe tucked out of the way. The wires to the control valve may still be there, although they may have been clipped off or tucked away. And yes, do check that all the various hoses and ports are capped off. If you can get a vacuum hose routing diagram for your spider, that would be helpful to make sure everything goes where it should, or is capped off.

However, I'm still puzzled because, since your transmission switch is disconnected, then the EGR system (what's left of it) shouldn't care which gear the transmission is in. But, I have another idea, and we'll get to that when you have a chance to do some more checking.

-Bryan

[CharlieB]

Well I found at least part of the problem. The caps on the carb ports were good. I have a cap on the 'T' that goes from the intake manifold to the brake booster. That cap was split so I replaced it. The car cranked right up and idled great in the driveway. I did set the idle speed a little higher (900 or so). The test drive went well. No stalls at stop signs or turns. However, just before I got home I shifted to neutral and hit the brakes hard. Just after I lifted my foot off the brake pedal, the car cut off.
I'm not sure what that means.
Bryan, I'm glad you brought up the EGR system, otherwise I would have never thought about checking those caps. The issue is definitely MUCH better than before. I will go ahead and replace the Idle Stop Solenoid and rewire it...somehow.
Thank you very much for the help. I'll keep you posted.
Charlie