Technical Cinq stinks of fuel and high emissions

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Technical Cinq stinks of fuel and high emissions


New member
Mar 18, 2013
I have a couple of Cinquecentos. They all have issues. To start: 1 of them stinks of fuel when I boot it or when the tank is 3 quarters full or more. I have replaced the fuel tanks in all of them and the fuel pump seals don't fit well on any of them because of the ridiculous 6mm nuts that have awful threads on them. There are no leaks from any of the tanks.

I was reading about the evap system. I have it on all 3 of them. Any idea if this relates to the smell or any way to check the evap system is working ok? Any way to get rid of it and keep the car working ok without it?

All 3 have branch manifolds on them and 2x have 866 cams and 36mm throttle bodies on them.

I also read about a guy in Portugal who sorted the fuel smell with replacing the o-ring on the injector. Does anybody know what this o-ring might be?

The other issue is the high emissions. Sort of nearly 3 times higher than normal high emissions. I have bought a new cat and map sensor in an effort to lower the readings. Timing is spot on with the car. The inlet manifold temp sensor was replaced not long ago

Strangely enough on this Cinquecento the tank vents when I open the fuel cap as if depressurising. Is this normal? My other 2 do not do this. Is my breather pipe blocked?

If anyone has any tips on how to get the fuel pump rubber seal to seat nicely and the 6mm nuts to actually tighten down well please let me know.

Think that's it for now.
Is the fuel smell more at the rear of the car or the front?

I have found the fuel tank are a bit of a nightmare to seal 100% sometimes. You do have to be careful with the nuts as you can strip the threads if you aren't careful. I've never had too much trouble doing them up though?
the plastic pipework from the filler neck to the tank can develop splits with age, with the arch liner removed you should be able to inspect them.