Idle Stop Solenoid revisited

[18Fiatsandcounting]

If the idle was running rich for whatever reason, the partially clogged idle jet may have actually improved things as it would tend to lean out the mixture when idling, and perhaps your periodic stalling is due to this idle jet clogging/unclogging/reclogging, etc. Try a new idle stop solenoid with a clean idle jet and see if that helps.

As for the ballast resistor, I think Kilrwail has it right. If your coil specifies a ballast resistor, you likely need one and it may be internal to the coil, but if you replace the original coil with a modern coil that doesn't require a ballast resistor, then you don't need the resistor. In a nutshell, ignition coil ballast resistors historically were there to limit the current or voltage (or both) in the primary winding of the coil to promote longevity.

See: http://www.circuitstoday.com/ballast-resistor

-Bryan

[CharlieB]

Thanks guys, i just wanted to make sure I got the right one. I'll get that and a new idle stop solenoid and leave you guys alone...for a few days anyway.
I'd be totally lost without you guys and everyone else on this forum.
Thanks again,
Charlie

[CharlieB]

Well miracle of miracles...the new coil seems to have fixed the stalling issue. I have not wired up the new idle stop solenoid yet, but the car is running great except the idle is a little high, but I'll address that tonight.
Thanks for the help with this guys, drinks are on me.
Charlie

[kilrwail]

I'll take single malt Scotch, Irish whiskey or bourbon, thanks. Where are you?

[CharlieB]

Peter I'm in Cincinnati, but always looking for a reason to escape to Canada.

[kilrwail]

I thought you might be somewhere along I-81, where I travel en route to Florida in January. Come on up - I'm only 11 hours away LOL

[18Fiatsandcounting]

I'll have to let the two of you party on without me, seeing as how San Francisco is a bit far... And besides, it was Kilrwail's suggestion on replacing the coil, so I think he should get the free drink!

Speaking of which, I just finished replacing the entire exhaust system on my '71 spider today (manifold to tailpipe), so I think it's pretty close to cocktail hour on this end. Only one minor leak that I'll address tomorrow.

-Bryan

[kilrwail]

I'm with you Bryan. I just replaced all the fluids in mine plus the coolant hoses. It's been a busy couple of days and I need a break.

Enjoy your driving Charlie!

[CharlieB]

Well don't break out the booze just yet. I hate to say it, but it's cutting off when i slow to a stop again. I still have not attached the new idle stop solenoid. I'll try to do that this weekend. It ran great after I installed the new coil. I didn't drive it again until today and it was back to it's old ways. I'll keep you guys posted.
Cheers,
Charlie

[kilrwail]

When you slow to a stop sign and it starts to cut off, is the clutch pedal depressed? If you pop the clutch before it stops running, does it restart? I think we've changed everything in the ignition system except the ignition switch. Odd problems that defy diagnosis usually lead us to that switch. Has yours been replaced or rebuilt?

[dinghyguy]

i know you changed the fuel filter, but is it still clean?
how about the engine ground from the bell housing to the frame, is it still good?
jiggle the ignition wires at the white connector while running, maybe something will change.....
No vacuum leaks?
does it miss before it dies or just lose revs and die?
does it do it with the air cleaner off or open?
I know you have had the carb in and out, when you had it out did you shake it to make sure you could hear the little ball check from the accelerator pump chamber rattle freely?

Not sure nay of these are directly the problem but they could be items to rule out....

cheers
dinghyguy

[CharlieB]

Peter,
It will start to cut out as soon it is taken out of gear. So if I'm still in a gear than its fine. As soon as I take it out of gear, the tach falls quickly. So, if I'm slowing down and downshift, it runs fine. As soon as I push the clutch pedal at a stop sign, the tach falls to zero. Also, if I'm driving along at any speed and shift into neutral, the tach falls. If I'm on flat ground, I can usually press the gas pedal and prevent the engine from cutting off. I can't do that on a hill obviously.
So basically the 2 events that make the rpm fall:
1) Foot is not on gas pedal
2) Car is out of gear
I have not installed the new idle stop solenoid yet, my wiring has been severely tampered with by the previous owner so I need to figure out the best way to wire it from scratch.
I'm certainly open to suggestions on that.
Thanks,
Charlie

[kilrwail]

Charlie - PM your email address to me and I'll send you a wiring diagram for a 78. It looks like you could tap into the pink wire coming off the ignition switch.

[CharlieB]

Dinghyguy,
I did change the fuel filter and I totally forgot to get the clear type. I'll get one this weekend.
I have checked the ground strap (the heavy white cable) and cleaned the connection, so all is well there.
I'm glad you mentioned engine miss. The car does have a slight miss. Its a quick stutter that usually only happens either when I'm driving in 3rd gear or above (once every minute or so), or when I'm starting off in first gear (rarely).
BUT to answer your question, it does not miss before cutting off.
I have not driven without the air cleaner to see if it cuts off. It does idle fine sitting in my driveway, either with or without the air cleaner.
I did not shake the accelerator pump when I cleaned the carb. I'll do that tomorrow.
I have tried shaking the ignition wires when it's starting to cut off, but no change.
I've tried to find vacuum leaks but none found.
Thanks,
Charlie

[CharlieB]

Peter, PM sent...I think.