Skip the auto shop - Our mechanics make house calls

Q: Possible fuel pump problems?

asked by on

I have a 1994 Chevy 2500 4x4 with the 454 big block. We have replaced countless sensors, the cap and rotor, the throttle body sensor, a knock sensor, etc. I am beginning to think the fuel pump/filter may be an issue.

The truck runs great when we can get it started. However, it's getting the vehicle started that's the issue. If you dump a bit of gas in the carb it fires right up. Then you can shut the vehicle off and fire it right up again. However, if the vehicle sits overnight, or for a few hours (especially in the rain or morning dew), it once again will not start until a small amount of gas is poured in the carb. Could this be a fuel pump failing, or possibly something else? It's throwing me off, because once the truck gets started it runs like a champ and has no problems what so ever.

My car has 200000 miles.
My car has an automatic transmission.

A: Assuming you have the stock equipment still...

Assuming you have the stock equipment still in your truck, it should have come with throttle body fuel injection and not a carburetor. If this is the case, you likely have a low fuel pressure issue that is preventing the fuel system from priming upon starting. First, try checking to see if you hear the fuel pump come on when just turning the key to the on position (should be a slight buzzing sound). If this does come on, then you know the fuel pump is working and getting power. Secondly, you may want to check the fuel pressure. The fact that the truck will run once primed with fuel suggests that you may have a fuel pressure regulator problem as it is able to maintain once it is initially primed with fuel, but unable to do this on it’s own upon start up. Here at YourMechanic, we can have a technician come to your home or office to inspect and diagnose this issue for you, and make or suggest the necessary repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Truck starts to hesitate under load

This may be related to low fuel pressure or potentially a failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to...

Q: Warning signs of a bad fuel pump. Like sputtering when idle. Bad fuel efficiency. Shaking when at higher speeds. Less acceleration

This may be related to many different things such as: a bad fuel pump, dirty fuel injectors, a clogged catalytic converter, a faulty O2 sensor, or a bad mass air flow sensor. Unfortunately, there are many possibilities that can cause...

Q: Stalling issue

A rough idle may be caused by many different things such as low fuel pressure, low voltage to the fuel injectors, dirty fuel injectors, a vacuum leak, a faulty Oxygen sensor or a dirty or failing idle air control valve....

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...