Technical Engine stopped fiat 500
- Thread starter gsc1ugs
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Technical Engine stopped fiat 500
Battery or main engine earth cables would be the first 2 things I'd check before looking deeper
When was the cam belt last replaced?
Could be a simple sensor, fuel or spark
Could be a simple sensor, fuel or spark
Its chain, there is no spark
Question about 'No Spark'.
Is the coil block an intelligent device?
I have noticed two pins in mine when cleaning plugs, but one could be power (with ground going through casing via mounting bolts) and the other could be high speed CANBUS.
Anyone know?
Is the coil block an intelligent device?
I have noticed two pins in mine when cleaning plugs, but one could be power (with ground going through casing via mounting bolts) and the other could be high speed CANBUS.
Anyone know?
Cranksensor? Does the rev counter move while cranking?
gr J
gr J
Chain?
Is it a diesel engine?
If it's the 1.2 Fiat engine then it's a belt, think even the 1.4 is a belt, as far as I know only the diesel is a chain
If it's the FIAT petrol engine then it's a belt driven cam.
So, no spark at all from any of the plugs? If the belt is broken I'm not sure whether the cam position sensor would stop sparks altogether because it's function is to help spark timing (so the sparks may happen but not necessarily at the right time - as Eric Morecambe would have said) however it's not too hard to slacken the top cover and have a look at the belt. Mind you, if the belt is broken or has jumped a number of teeth then it being broken is the least of your worries as these are interference engines (as far as I know).
More likely to be the crankshaft sensor or associated plugs and wiring. It wouldn't harm to split any connectors and examine internally for poor connections - often just disconnecting and reconnecting a connector is enough to reestablish a circuit. For that reason I'd also try separating the ECU plugs and making sure the internal connections are sound. Unlikely to be the ECU itself, but not completely impossible.
Edit. Reference the possibility of it being a broken belt. If the belt is broken then the valves won't be opening and closing so the engine will spin freely and rapidly without the characteristic slight slowing as it goes over compression on each cylinder. If it sounds "normal" when cranking then the belt is likely to be intact. Of course it may have jumped a tooth or two but I'd still expect to see a spark. If the belt isn't driving the cam then the engine will spin fast and at constant revs because there's no compression to overcome.
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Engine cranks but does it crank nice and fast? The earth strap mentioned near the top of this thread is, on the Fiats, prone to corrosion and failure. On the Fiats it is under the battery box running from a gearbox bolt to the N/S chassis leg. You say the battery is "new" but is it well charged? If not really healthy the load the starter puts on it when cranking can drop the residual battery voltage to the point where it drops below the threshold voltage at which the ECU can operate. So you end up with an engine which cranks but plugs don't fire. However under these circumstances I'd expect cranking to be quite slow and laboured. Doesn't sound like this is your problem.
Edit. Crankshaft sensors do fail but often there is "history" leading up to the failure, typically acting up when hot. So miss fires with a hot engine or maybe reluctant to start when the engine is hot.
Edit. Crankshaft sensors do fail but often there is "history" leading up to the failure, typically acting up when hot. So miss fires with a hot engine or maybe reluctant to start when the engine is hot.
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The 4 cylinder petrol engines have a belt driven camshaft; the diesels and TA use a chain.
The engine obviously won't start with a snapped belt, but that said, belt failure is most unusual and almost never reported on this forum.
Chain failure reports on the diesels are, however, reported quite frequently in comparison.
