How to: Listening For a Fuel Pump

[ExplorerDMB]

For a no start or cranking issue - and you want to rule out the fuel pump circuitry, you can simply listen to hear the fuel pump cut on with the key turned to the ON position. This will "prime" the fuel system, meaning fuel will be pressurized into the rails. Now, to make it even easier to hear, have a friend sit in the driver seat, put a funnel (long transmission funnels are best) into the fuel tank filler neck, and get your friend to turn the key on. You should be able to hear the slightest noise inside the tank.

-Drew

NOTE: just because you hear a fuel pump cut on, doesn't mean the pump is good. It basically just means the Fuel Pump/Sending Unit circuit is ok.

 

[TarHeel085]

also, just to add, as a general rule a good pump will make a high pitched whine. while a pump that is bad or going bad will be lowered pitch, more like a groan.

 

[skoal_mint]

and it will only be for 2-3 seconds, but like ExplorerDMB it doesnt mean its working fine, their should still be a pressure test done

 

[NapalmMan67]

So if you turn the ignition to the "On" position, and get no 5 second prime buzz, and get no steady buzz from the pump...

Engine ran fine 7-8 months ago when parked, but no prime switch/fuel pump noise now. Battery is charged, engine cranks ok and spark is good.

 

[skoal_mint]

yes, so if you dont hear any noise at all then check ur relay, the kick off switch..

use a volt meter and check the voltage to all, if that good then its you pump...i rember fixing one befor and all it was is the wire that went to the pump, it was cut somewhere in the middle and the connector switch was was dirty and i was getting a low voltage so the pump would not give enough pressure

 

[ExplorerDMB]

Check your voltage at the pump. That test the WHOLE curcuit. Also check for a ground.

-Drew

 

[B.T.]

I change dthe fuel pump and fuel regulator in my 91 explorere. Ran good for about a day then the cranking time went to 3-4 secs before starting. It also had no power once during exceleration today. If you shut the engine off then retart it starts right away. Anybody have a idea or suggestion ?
Barry

 

[410Fortune]

check your fuel pump relay

 

[mmwb]

So where is the pump relay?

 

[BlacKnight]

On a 1991, look under the hood on the passenger side fender. You should see some relays in front of the blower motor. If you have the original relay, it should have a number like "F19B 9435-A2A" stamped on it. Otherwise, it might show "F8PJ 14N135-AA" if it has been replaced before.

 

[bikerted86]

If you have a long crank time after letting the car sit it is usually a issue in the pump or pressure regulator. If either one of them is letting the system bleed down you can end up with air in the fuel lines. if there is any way for you to pinch off the return line without damaging anything. Pinch off the line right after priming the system a couple times and check if there is a pressure drop (works best with gauge), if there is a pressure drop then you have a issue with the pump, If there is no pressure drop you have a issue with the regulator.

 

[jollyr]

code 542

I have a quick question iam getting a 542 code on my 87 ranger 4x4 it has a 92 4.0 in it the fuel pump runs when you turn the key on, but it keeps running even if you dont start it and can hear it blowing air bubbles in the tank ? its has the low pressure in the tabk and the high pressure on the frame the truck run great i just need to get rid of this code so i can get it smoged. with an eng. swap in calif. it can,t have any codes in any test. thanks for ant help that you can give me.

 

[fex98]

For a no start or cranking issue - and you want to rule out the fuel pump circuitry, you can simply listen to hear the fuel pump cut on with the key turned to the ON position. This will "prime" the fuel system, meaning fuel will be pressurized into the rails. Now, to make it even easier to hear, have a friend sit in the driver seat, put a funnel (long transmission funnels are best) into the fuel tank filler neck, and get your friend to turn the key on. You should be able to hear the slightest noise inside the tank.

-Drew

NOTE: just because you hear a fuel pump cut on, doesn't mean the pump is good. It basically just means the Fuel Pump/Sending Unit circuit is ok.

I have no power to my pump the pump is new the relay is working I did replace the kick off switch and it did work 3 /4 starts and now back to the doing the same thing I am running a wire from the pink wire in the plug to the kick off switch straight to the battery just so i can drive it pain in the ass because I pop the bonnet an dpull wire every time Iturn it off .
Darren please help