You’ve heard of mixture distribution problems relating to carburetors—different cylinders receiving different amounts of fuel. This is caused by many variables, including g-forces and poor manifold design.
If one cylinder is receiving a different amount of fuel, it means that the air/fuel ratio varies in each cylinder and, as a result, the engine will not run at its peak. This wreaks havoc with fine-tuning and not only at the dragstrip. Around-town driveability and mileage will suffer as well.
Carburetors are the worst offenders, but the same thing can happen with electronic fuel injection, including direct-port systems such as GM’s tuned-port and LT1 units.
The direct-port systems use separate injectors for each intake port, so a proper amount of fuel can flow into its assigned cylinder. Therefore, mixture distribution should be trouble-free. But reality suggests otherwise, as injectors get plugged, dirty or mismatched, resulting in distribution problems. Flagrant fuel-delivery problems with injectors can be the cause of a rough idle or cause a bog in throttle transition. They will often be spotted by reading the plugs, but minute differences can be hard to discover with the injectors in the engine. This means the injectors must be removed, inspected and, if necessary, gone through. Brad Urban from The Carburetor Shop demonstrated the difference in fuel flow with a set of eight injectors.
The Carburetor Shop has the equipment to inspect, rebuild and match the injectors so that each one delivers the same amount of fuel. The shop will check, clean and blueprint your injectors for $35 each and will provide an Injector Test & Clean Report.
