Stalling issue

Hi Everyone,

I finally reinstalled my engine and transmission with a new clutch in my 1975 fiat spider.
I’ve managed to get it started and idling nicely, but when I put it in gear, as soon as I begin
to let the clutch out, it stalls. It’s as though it triggers a kill switch.
Not sure if it has something to do with the clutch safety switch…?
I tried jumping it in case the switch is bad, but that wasn’t it.
Maybe a vacuum leak/
Though I would think a vac leak woudn’t let it idle and rev nicely which it does.
Please help…!
Thank you.


Double check your timing.

Do you have a schematic for the ignition system? Does the vehicle have a safety switch that requires the clutch to be pushed in to start the engine? Typically that will energize a relay that allows the ignition circuitry to be enabled. The relay remains energized until the engine is again shut off. The purpose of the system is to not allow the engine to be started with the clutch engaged.

If it does, and that relay does not remaining enegized, the ignition circuitry will be disenabled when you let the clutch out.

I’m just guessin’ here, but I thought of it so I thought I’d post the idea.

On most cars – like my Corolla for example – the clutch safety switch is only involved with the starter motor, not the ignition system. But a Fiat 124 isn’t most cars. As posted by TSM you need to secure a schematic. If you can post it here, maybe somebody can spot the problem just by looking at the schematic.

Does it seem to start moving before it stalls? Or does it stall even before the clutch begins to engage? One thing you should do – probably already have – is make sure there’s no wires or sensors being pinched by the movement of the stuff between the pedal and the clutch that occurs when you press and release the clutch pedal.

It’s possible also that the engine isn’t running as well as you think, and can’t handle the load of the clutch being engaged. Seems unlikely if it idles well and is spritely when the gas is juiced at idle. What does the intake manifold vacuum read at idle and when you give it some juice at idle?