Signs of a Bad Corvette Fuel Filter
Reprinted with permission from NCOA Newsletter forVettesonly
Written by: John Gunnell
If you have an older Corvette, you're probably used to replacing the fuel filter from time to time. On the other hand, fuel filters aren't a regular replacement item for late-model Corvettes that employ more modern powertrain control and management systems.
Since Chevy switched to fuel injection, the service life of fuel filters has increased dramatically. Other changes ranging from improvements in fuel storage and delivery at a gas station to larger filters with dramatically increased surface areas also factor into the equation. Today, you have Corvettes with computers that can make precise adjustments to fuel control on an immediate and long-term basis. This eliminates early filter problems.
Fuel filter replacement is often overlooked by today's techs, but that's not a good thing. Keep in mind that the fuel filter is there for a good reason. If you don't replace it, you'll eventually get bad stuff coming through it that can start clogging it up and that will ultimately restrict the flow of fuel and create drivability problems in your Corvette.
Owners of both classic and late-model Corvettes should know about the signs that a fuel filter is due for replacement. And if you're part of the late-model contingent, don't look for a trouble code flashing on the dashboard, because you're not going to see one. Pinpointing fuel filter problems is an "Old school" talent based on symptoms you know.
A noisy fuel pump is one indication of a bad fuel filter. You've probably never heard a peep out of your Corvette's pump, but if it starts to scream and screech, there's a problem going on. A fuel pump that's noisy is a sure sign that the fuel filter needs to be changed.
The fuel pump may get damaged if a restricted filter is ignored. Also, remember to install a brand new fuel filter any time you put a new or rebuilt fuel pump on your Corvette.
Although a bad fuel pump itself won't trigger a diagnostic trouble code (DTC), later-model Vettes may exhibit DTC P0171 (System Too Lean Bank 1) and DTC P0174 (System Too Lean Bank 2) codes.
These hint that the fuel filter is bad. The codes probably indicate the powertrain control module (PCM) monitoring the Corvette's exhaust gases senses there isn't enough fuel for proper combustion in one or both cylinder banks. The PCM will then enrich the air/fuel mixture to compensate for the lean-running condition. Trouble codes will show up if the condition lasts a while. They indicate a bad fuel pump.
A Corvette with a bad fuel pump will be slow to crank over and won't start up normally. An electric fuel pump is primed by turning the key to "on" or by unlocking and opening the driver's door. A restricted filter will up the cranking action needed to force the fuel into the carburetor or injectors. A mechanical pump primed by gas pedal pumps can do the same.
With a bad fuel filter, your Corvette may hesitate when you accelerate.
You may also feel power drop off when you increase the load on the engine by speeding up or giving it more gas to climb a hill. With a fuel filter restriction, the engine won't be getting enough fuel to give you the performance you want on demand and it might start to bog down.
Fuel-pressure sensors are now starting to become more common. If you get a DTC code on a late-model Corvette indicating low fuel pressure or lack of fuel pressure, it may be because a clogged fuel filter is contributing to the low fuel pressure problem.
Aging, service life limitations and mileage can also be considerations for installing a new fuel filter in your Corvette. If it's been a lot of years or a lot of miles since you last changed your fuel filter, it will probably pay to do so the next time the car is service. Fuel filters aren't very expensive and can be owner-installed easily enough.