Skip the auto shop - Our mechanics make house calls

Q: Why does my Tahoe start with the fuel pump relay pulled out or left in?

asked by on

I been having starting problems at times.. My 1998 Chevrolet Tahoe with the 5.7 Vortec will crank right up then die.. Then you try to crank it again and it fires up and it's fine it seems the rest of the day.. I'm just puzzled I can't understand why it starts with the Fuel Pump Relay pulled out and with it in? I was told to pull the relay and see if it stopped it from starting. I was told it should not start with Fuel Pump Relay out ,, but funny thing it does start an run.. My question is..Is my Fuel Pump Relay bad??

My car has 220000 miles.
My car has an automatic transmission.

Hi there. Check to see what relay you have pulled. If indeed you removed the fuel pump relay and the engine still starts up, then check the oil pressure switch. An oil pressure switch will kept the engine running as it passes battery voltage to the fuel pump. When the engine builds up oil pressure, the oil pressure switch sends voltage to the fuel pump and bypasses the fuel pump relay. Unplug the oil pressure switch and see if the engine stops running. If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from Your Mechanic, who can assist you with why your vehicle is still running with the fuel system relay removed.

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!
  • Home
  • Questions
  • Why does my Tahoe start with the fuel pump relay pulled out or left in?

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: Engine cranks but wont run. Power not reaching fuel pump

This sounds like you may not have any power going to the fuel pump relay. The relay wires should have ground on two wires, power on one wire and switched power on another wire. To activate the fuel pump your...

Q: The car cranks but it won't start

Fuel pressure and ignition spark need to be checked. Also, having fault codes checked in the engine computer is also necessary as hard faults that may prevent the vehicle starting could be stored. A faulty ground will generally be accompanied...

Q: Rough Idle after warm up

It sounds as though you may have a misfire. You didn't mention a check engine light, but normally a misfire would turn it on.Try turning on the key but not starting the car. The check engine light should be lit...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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 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.