Tuning Cracking and Popping

[SDHXIII]

Hello,

I'm having a bit of trouble with the 650cc engine in my FIAT 500.

Until recently it had Been running better then ever, but the last two times I have started her up she has felt a bit rough and she now cracks an pops almost like a mini backfire?

I have today checked the tappets, they were pretty much spot on, had a look in the carburettor which looks as clean as ever.

I have uploaded a video, link below, please let me know your thoughts and suggestions, I'm hoping something very simple.

Thanks for any suggestion.

Stu...

https://youtu.be/6r0PXO5zOow

 

[Toshi 975]

Hello,

I'm having a bit of trouble with the 650cc engine in my FIAT 500.

Until recently it had Been running better then ever, but the last two times I have started her up she has felt a bit rough and she now cracks an pops almost like a mini backfire?

I have today checked the tappets, they were pretty much spot on, had a look in the carburettor which looks as clean as ever.

I have uploaded a video, link below, please let me know your thoughts and suggestions, I'm hoping something very simple.

Thanks for any suggestion.

Stu...

https://youtu.be/6r0PXO5zOow

What you describe is sometimes associated with the condenser starting to break down.

 

[the hobbler]

As Toshi says, it sounds like the start of the condenser breaking down. The 500s have a nasty habit of going through condensers quite rapidly. Part of the problem is that, being attached to the distributor, it gets very hot---and condensers don't like heat. The 2nd reason for condenser failure is that a lot of modern condensers are made very badly. They are relatively expensive, but I always reccommend the "Swiftune Competition" condenser. (a) it is very well made and (b) it can be located up alongside the coil, away from the 'cooling' hot air.

 

[FR85]

Mine is the exact same, not sure about the condenser as I've an electronic ignition fitted.

Also does this during engine braking or if you give it a rev from idle in neutral as its slowing down back down to idle.

I just live with it as Ive been through valves, plug leads, plugs, coil and cap. :bang:

 

[SDHXIII]

Thanks for the ideas re the condenser. Now I'm really confused!! I have got a Powerspark electronic ignition set up, but still have the condenser bolted on? I will have to have a look to see if it is connected or just there for aesthetics.

 

[the hobbler]

If you have ANY electronic ignition you do NOT require the condenser---remove it.

 

[LiteRye]

While I don’t have an answer to your popping issue, I would recommend the removal of the fuel filter before the fuel pump. It’s not needed and is a fire hazard.

 

[fiat500]

Thanks for the ideas re the condenser. Now I'm really confused!! I have got a Powerspark electronic ignition set up, but still have the condenser bolted on? I will have to have a look to see if it is connected or just there for aesthetics.

Check that it is actually a condenser. Recently, someone here had boought a car with a suppressor fitted, which was not needed on their vehicle.

 

[FR85]

While I don’t have an answer to your popping issue, I would recommend the removal of the fuel filter before the fuel pump. It’s not needed and is a fire hazard.

Good call and well spotted, I've moved mine to on top of the tank, loads of space on the pipe there.