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.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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 is not getting fuel until holding the ignition in for a few seconds.

You may very well be on the right track with this and you should check the control module to be sure. You may also want to check the fuel pressure regulator as well to be sure you are getting enough...

Q: How I replace fuel filter

The fuel filter for your car is in the fuel tank. If you want to replace it, you will need to replace the fuel pump. It isn't regularly serviceable item anymore. As for the codes, the P0172 indicates there is...

Q: Car squirting oil and smoking

Hello. This is a sign of an oil leak. If the oil is squirting from the motor only when the car is running, this helps to narrow down where since that means it is coming from a place that is...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.