How does a faulty fuel cap affect fuel efficiency in Changan Kalam?

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How does a faulty fuel cap affect fuel efficiency in Changan Kalam?

Some owners report a in mileage after fuel cap issues. Is this just perception o r is there a real connection between cap sealing and fuel economy?

Zarnish asked on 24 Jun 2025 17:16:34 pm

1 Answer

21 views |

Car Mechanic Expert - on 24 Jun 2025 17:20:27 pm

While the effect is small, it’s real:

If the cap is loose o r leaking, it can cause the fuel system to remain vented, allowing fuel vapors to escape rather than be reused.

This disrupts the air-fuel ratio, leading to slightly richer combustion, reducing mileage.

Also, if the CEL is on, the ECM may disable fuel-saving strategies like lean burn mode, indirectly affecting efficiency.

So yes, a faulty fuel cap can reduce fuel efficiency, especially over long drives.