General Engine hunting and fuel gauge fluxuating

[Samgarrett88]

Hi all,

Took the Cinquecento out for a long drive to a car show since fitting a 40mm throttle body, on the way there it drove really well but on the way back I was getting issues, fuel gauge going up and down between almost full and half full and when idling it was going up and down the revs between 1000rpm and 500rpm. Can't hear or feel any air leaks, could it be the the ecu learning as it was idling at 1000rpm to begin with but this doesn't explain the fuel gauge problem, any ideas?

 

[blu73]

hunting is most likely an vacuum leak, spray some carb cleaner or brake cleaner around the TB while its idling and it'll rev up a bit if you spray on a leak.

 

[Samgarrett88]

Could the hunting be down to the ecu still learning from the new 40mm?

hunting is most likely an vacuum leak, spray some carb cleaner or brake cleaner around the TB while its idling and it'll rev up a bit if you spray on a leak.

 

[blu73]

i doubt it, ive stuck 40mm tb on lots of centos and thats never happened - my guess would be the spacer under the TB isnt 100% sealed

 

[Terry899]

Had the same issue a few years ago in my cinquecento, turned out the new map sensor died. New parts aren't as good as the original ones so I had a second hand one and it still works as good as new. Also during my reassembly of the throttle body I put 2 vacuum hoses in the wrong place, simply swapping them around brought the idling back much better. I was relieved as the problem is like looking for a needle in a haystack