Corvette Fuel System Maintenance - Fuelish Behavior

A Corvette Fuel-Injection Cleaning And Maintenance How-To

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A preferred method for cleaning fuel injectors is with an ultrasonic fuel-injector cleaner/fuel injector flow bench, such as the ACE/ASNU unit shown.

The fuel-injection system that supplies the fuel to each cylinder of the engine in an '85-or-newer Corvette is so reliable that it seems to be almost maintenance free. The engine's fuel-injection system may be low maintenance, but it does have fuel-related components that need maintenance from time to time, such as the fuel pump, fuel filter(s), and the fuel injectors. The fuel injectors can-and most likely will-get "dirty" or contaminated by the deposits that gasoline forms in the fuel injectors as the gasoline flows through them.

How do you know when your fuel injectors need cleaning? The symptoms you will most often experience will be a gradual loss of engine power and/or a stumble/hesitation on acceleration as the fuel injectors in your Corvette get "dirty." These symptoms may appear so slowly with time and miles of driving that you may not even notice any problems. If you happen to get a bad tank of gasoline at some point, these problems can appear very quickly.

The port fuel injectors are located in a very hot area in the engine, and the injectors are subject to deposit build-up problems created by the high-temperatures effect on the fuel as it flows through the fuel injectors. The high underhood temperature that is common after you shut off your engine will also cause deposits to build up as the fuel boils in the injectors. These deposits will eventually distort the fuel-injector spray pattern and restrict the fuel injector's ability to supply the engine with the correct volume of fuel.

Diagnosing the Fuel-Injection System
The use of an automotive computer diagnostic scan tool is the best way to diagnose the fuel system in your Corvette. You can take your fuel-injected Corvette to a qualified shop that has all the latest diagnostic tools, or if you want, do the work yourself. There are many low-cost computer scan tools on the market that are user friendly.

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This "dirty" fuel filter was removed from a fuel injector. Once the "dirt" gets by the inline gas filter, it can plug the filter built into the fuel injector.

The long-term fuel trim data ('96-and-newer Corvette w/OBD-2 computer system) or the block learn data ('85 thru '95 Corvette w/ OBD-1 computer system) obtained from an automotive computer diagnostic scan tool can be used to read how much the computer is adjusting the fuel-injector pulse width so the engine has the correct air/fuel mixture. When the fuel-injector flow becomes restricted as the injectors get dirty, the computer will attempt to adjust the fuel flow by opening the injector longer through the use of its long-term fuel trim function. Fuel injectors that are dirty will need more pulse width (held open longer) than injectors that are flowing the correct volume of fuel for the engine's needs. If the injectors are leaking fuel, the computer will adjust the amount of fuel coming from the injectors by subtracting fuel through use of its long-term fuel trim function. The engine will perform its best when the computer does not continually have to correct for fuel injectors that are not supplying the proper volume of fuel.

Cleaning the Fuel Injectors
If the fuel injectors are "dirty" or leaking, there are several different options available to clean the fuel injectors. The options include:

1.A fuel-injector cleaning chemical that you pour into the fuel tank can be used to clean the injectors. We have had good results using an in-tank fuel injection cleaner such as Techron Concentrate Plus from Chevron. Several of our customers have told us they felt a noticeable increase in power with just one tank of gasoline treated with the cleaning solution in the tank. The disadvantage of the in-tank fuel-injector cleaning method is it does not allow you to check the fuel-injector spray pattern, plus the fuel "filter" built into the fuel injector may become plugged with any contaminants that may be washed into it. If the in-tank method does not supply the desired results, you may need to try another injector cleaning method.

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