Fuel pump problems?

[Yamero]

The truck started this noise yesterday. Is this the fuel pump? Is it going to give out soon? I don't know how to upload a video so I put it on a youtube link. This is taken by the rear wheel passenger side



Thanks for the help!

[PorknBeans]

I hear a whirring sound in the video.

I’ve never known a fuel pump to drone on. It will usually just work or it won’t. But I will say it’s not the fuel pump.

Could possibly be the drive shaft’s carrier bearing. But the truck would need to be moving. I believe your truck is stationary in the video.

If you buy a mechanic’s stethoscope. You can place the “listening tube”(for lack of a better description) directly where you want to listen and observe and pinpoint noises to make a solid decision if the component is making the noise. A stethoscope really is a valuable and inexpensive troubleshooting tool. A piece of fuel, vacuum or water line can also be used. But for hard to reach places. This tool is what I choose. Easy to reach places to listen to like fuel injectors, alternator etc. and a piece of hose works just fine. Hard to reach spots…stethoscope.

But I can’t think of any other component (s) in the rear that have moving parts, except the EVAP solenoid or the EVAP Vent Valve attached to the Charcoal Canister. These parts wouldn’t make any noises but a clicking sound and wouldn’t be heard over the engine noise. But your truck might have these parts located under the hood. Mine’s out rear.

Maybe someone else can come up with something else that can help you further…

[Yamero]

Originally Posted by PorknBeans

I hear a whirring sound in the video.

I’ve never known a fuel pump to drone on. It will usually just work or it won’t. But I will say it’s not the fuel pump.

Could possibly be the drive shaft’s carrier bearing. But the truck would need to be moving. I believe your truck is stationary in the video.

If you buy a mechanic’s stethoscope. You can place the “listening tube”(for lack of a better description) directly where you want to listen and observe and pinpoint noises to make a solid decision if the component is making the noise. A stethoscope really is a valuable and inexpensive troubleshooting tool. A piece of fuel, vacuum or water line can also be used. But for hard to reach places. This tool is what I choose. Easy to reach places to listen to like fuel injectors, alternator etc. and a piece of hose works just fine. Hard to reach spots…stethoscope.

But I can’t think of any other component (s) in the rear that have moving parts, except the EVAP solenoid or the EVAP Vent Valve attached to the Charcoal Canister. These parts wouldn’t make any noises but a clicking sound and wouldn’t be heard over the engine noise. But your truck might have these parts located under the hood. Mine’s out rear.

Maybe someone else can come up with something else that can help you further…

thanks for the information. Yes, the truck was stopped, it seemed to me it came from the gas tank, but I will look to get a stethoscope to pin point the issue.

[cadillacdude1975]

Get a mechanic stethoscope and see what you hear with the probe touching the tank.

[jp2code]

Is your truck also running in this video?

If not, does it run?

Assuming it is the fuel pump (can't tell), I'm trying to think of what would cause the fuel pump to run on like that. Perhaps the fuel pressure regulator is bad, so the fuel pressure is off. Or somehow the EVAP canister is sending too much fuel back to the tank, so the fuel pump has to continually run - but you would have a code if the EVAP were messed up.

When was the last time you pulled the codes?

Walkthrough: Checking Error Codes

[Yamero]

Originally Posted by jp2code

Is your truck also running in this video?

If not, does it run?

Assuming it is the fuel pump (can't tell), I'm trying to think of what would cause the fuel pump to run on like that. Perhaps the fuel pressure regulator is bad, so the fuel pressure is off. Or somehow the EVAP canister is sending too much fuel back to the tank, so the fuel pump has to continually run - but you would have a code if the EVAP were messed up.

When was the last time you pulled the codes?

Walkthrough: Checking Error Codes

Yes, the truck is running, but not moving on the video. It still starts on the first try. Does the code give a check engine light? I haven't checked the codes. Btw this is a 1991 base model 4 cylinder.

[jp2code]

Originally Posted by Yamero

Yes, the truck is running, but not moving on the video. It still starts on the first try. Does the code give a check engine light? I haven't checked the codes. Btw this is a 1991 base model 4 cylinder.

No, the only thing that throws the Check Engine Light (CEL) is emissions issues. They were federal requirements.

And a code reader won't work, either. Code readers are for OBD2 vehicles, and Nissan didn't do that to the Hardbody until 96.

[smith]

I have a 93 ka24e. Charcoal canister has no code, it's not monitored by the ecu (not solenoid operated). Mine is under the hood. There is a vacuum/air line going to the tank for vapors to escape the tank and for air to enter the tank (replace the fuel that is pumped out). This could cause a vacuum leak (noise). The fuel pump starts pumping with the key in "On" position and runs for, I believe 5 seconds to pressurize the system, and then shuts off. Check if you hear this noise without the engine running, I hear my pump pressuring the system from inside the cab without the engine on.