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Make: Fiat (as in Fix It Again, Tony)
Model: Mk1.2 Panda 750 (5 speed manual, pre-euro 1 (carb+manual choke))
Year: 1992
Kilometers: 73 000 (not to be trusted)
Recent reparations: Bougies, Bobine, Air Filter, Coolant tube, Idle speed uptune (all done home)

I have a carbureted 1992 Fiat Panda that runs into a strange issue lately.

One way or another, whenever the engine is cold, it is able to start while rolling, but as soon as I depress the clutch for a stop, it stalls.
It is now starting to get worse; to actually start the engine I now have to open the choke, pull the key, release the clutch, let the starter motor get the car in motion (!) and then the engine kicks in. And as soon as I press the clutch to stop the car it stalls again, only to become twice as hard to start.

This only applies to when the engine is cold; after 30 seconds of continuous driving the problem disappears. But not counting the fact that it would be very bad for both engine and starter, it is very annoying and even dangerous to limp on an intersection while the engine tries as hard as it can not to stall...

Could an engine require a minimum load to run (as opposed to a minimum speed)? Or would it be more like that the clutch is bad? The car seems to run smoothly aside from that little issue.

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  • Welcome to Motor Vehicle Maintenance & Repair!
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Sep 27 '17 at 22:38
  • I assume that every time it stalls you're also pressing the brake right? If yes, then I'd think something along the lines of replacing/repairing/adjusting your clutch. If however, this is happening when you're not pressing the brake, and it's just stalling whenever the clutch is pressed (and cold) the there's something else going on.
    – kyle_engineer
    Sep 28 '17 at 0:22
  • It happens too if I don't depress the brake, or if I put the car in neutral...
    – Yvar de Goffau
    Sep 28 '17 at 6:57
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It sounds to me like your carburetor needs setup properly. It is likely that your idle speed at on-choke running isn't set high enough. It's also possible that your auto-choke isn't working at all.

One question, before attempting to start the car, do you depress the throttle pedal fully to the floor once to engage the cold start circuit?

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  • As mentioned, my car doesn't have an automatic choke (it is the good old manual type; pull then pray) and I did recently augment the idle speed (it was way to low). Also, I do always depress the throttle pedal fully while starting, else it won't start at all.
    – Yvar de Goffau
    Sep 28 '17 at 9:31
  • In that case it may be either that the mixture screw at idle is set slightly too weak or that the carburetor has developed an air leak so is running more lean that it had be. This would likely align with whatever cause the idle speed to require adjustment. Carburetor to inlet manifold gasket is a favourite culprit. Partially blocked jets or fuel filters can cause the same behaviour.
    – Steve Matthews
    Sep 28 '17 at 10:56
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You are describing the classic signs of sticking valves (especially the exhaust valves).

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  • Please try to flesh this out a bit - how can the OP confirm this? what can they do to fix it?
    – Nick C ♦
    Sep 28 '17 at 9:16
  • I had a look on the internet, and although I didn't think about this one (I didn't even know such a thing existed) I will surely have a look. The symptoms are indeed correct!
    – Yvar de Goffau
    Sep 28 '17 at 9:34
  • Nick C - The valve stems bind/stick to the valve guides. There is no way to confirm this condition other than disassembling the heads. One possible fix, if due to deposits, is to substitute 1/5 of the crankcase oil with Marvel Mystery Oil (or automatic transmission fluid) for 3,000 miles.
    – Carguy
    Oct 2 '17 at 7:14
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I think the flywheel is binding when the clutch is disengaged and it acts like it’s in gear. Check the fluid for metal shavings.

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